[MODERATION] user blocking

- Add the ability to block a user via their profile page.
- This will unstar their repositories and visa versa.
- Blocked users cannot create issues or pull requests on your the doer's repositories (mind that this is not the case for organizations).
- Blocked users cannot comment on the doer's opened issues or pull requests.
- Blocked users cannot add reactions to doer's comments.
- Blocked users cannot cause a notification trough mentioning the doer.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/540
(cherry picked from commit 687d852480)
(cherry picked from commit 0c32a4fde5)
(cherry picked from commit 1791130e3c)
(cherry picked from commit 37858b7e8f)
(cherry picked from commit a3e2bfd7e9)
(cherry picked from commit 7009b9fe87)

Conflicts: https://codeberg.org/forgejo/forgejo/pulls/1014
	routers/web/user/profile.go
	templates/user/profile.tmpl
(cherry picked from commit b2aec34791)
(cherry picked from commit e2f1b73752)

[MODERATION] organization blocking a user (#802)

- Resolves #476
- Follow up for: #540
- Ensure that the doer and blocked person cannot follow each other.
- Ensure that the block person cannot watch doer's repositories.
- Add unblock button to the blocked user list.
- Add blocked since information to the blocked user list.
- Add extra testing to moderation code.
- Blocked user will unwatch doer's owned repository upon blocking.
- Add flash messages to let the user know the block/unblock action was successful.
- Add "You haven't blocked any users" message.
- Add organization blocking a user.

Co-authored-by: Gusted <postmaster@gusted.xyz>
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/802
(cherry picked from commit 0505a10421)
(cherry picked from commit 37b4e6ef9b)
(cherry picked from commit c17c121f2c)

[MODERATION] organization blocking a user (#802) (squash)

Changes to adapt to:

  6bbccdd177 Improve AJAX link and modal confirm dialog (#25210)

Refs: https://codeberg.org/forgejo/forgejo/pulls/882/files#issuecomment-945962
Refs: https://codeberg.org/forgejo/forgejo/pulls/882#issue-330561
(cherry picked from commit 523635f83c)
(cherry picked from commit 4743eaa6a0)
(cherry picked from commit eff5b43d2e)

Conflicts: https://codeberg.org/forgejo/forgejo/pulls/1014
	routers/web/user/profile.go
(cherry picked from commit 9d359be5ed)
(cherry picked from commit b1f3069a22)

[MODERATION] add user blocking API

- Follow up for: #540, #802
- Add API routes for user blocking from user and organization
perspective.
- The new routes have integration testing.
- The new model functions have unit tests.
- Actually quite boring to write and to read this pull request.

(cherry picked from commit f3afaf15c7)
(cherry picked from commit 6d754db3e5)
(cherry picked from commit 2a89ddc0ac)
(cherry picked from commit 4a147bff7e)

Conflicts:
	routers/api/v1/api.go
	templates/swagger/v1_json.tmpl
(cherry picked from commit bb8c339185)
(cherry picked from commit 5a11569a01)
(cherry picked from commit 2373c801ee)

[MODERATION] restore redirect on unblock

 ctx.RedirectToFirst(ctx.FormString("redirect_to"), ctx.ContextUser.HomeLink())

was replaced by

 ctx.JSONOK()

in 128d77a3a Following up fixes for "Fix inconsistent user profile layout across tabs" (#25739)

thus changing the behavior (nicely spotted by the tests). This
restores it.

(cherry picked from commit 597c243707)
(cherry picked from commit cfa539e590)

[MODERATION] Add test case (squash)

- Add an test case, to test an property of the function.

(cherry picked from commit 70dadb1916)

[MODERATION] Block adding collaborators

- Ensure that the doer and blocked user cannot add each other as
collaborators to repositories.
- The Web UI gets an detailed message of the specific situation, the API
gets an generic Forbidden code.
- Unit tests has been added.
- Integration testing for Web and API has been added.
- This commit doesn't introduce removing each other as collaborators on
the block action, due to the complexity of database calls that needs to
be figured out. That deserves its own commit and test code.

(cherry picked from commit 747be949a1)

[MODERATION] move locale_en-US.ini strings to avoid conflicts

Conflicts:
	web_src/css/org.css
	web_src/css/user.css
	https://codeberg.org/forgejo/forgejo/pulls/1180

models/activities/action.go

@@ -580,7 +580,7 @@ func NotifyWatchers(ctx context.Context, actions ...*Action) error {
 
 		if repoChanged {
 			// Add feeds for user self and all watchers.
-			watchers, err = repo_model.GetWatchers(ctx, act.RepoID)
+			watchers, err = repo_model.GetWatchersExcludeBlocked(ctx, act.RepoID, act.ActUserID)
 			if err != nil {
 				return fmt.Errorf("get watchers: %w", err)
 			}

models/activities/notification.go

@@ -235,6 +235,15 @@ func createOrUpdateIssueNotifications(ctx context.Context, issueID, commentID, n
 		for _, id := range issueUnWatches {
 			toNotify.Remove(id)
 		}
+
+		// Remove users who have the notification author blocked.
+		blockedAuthorIDs, err := user_model.ListBlockedByUsersID(ctx, notificationAuthorID)
+		if err != nil {
+			return err
+		}
+		for _, id := range blockedAuthorIDs {
+			toNotify.Remove(id)
+		}
 	}
 
 	err = issue.LoadRepo(ctx)

models/fixtures/forgejo_blocked_user.yml

@@ -0,0 +1,5 @@
+-
+  id: 1
+  user_id: 4
+  block_id: 1
+  created_unix: 1671607299

models/fixtures/repository.yml

@@ -37,7 +37,7 @@
   lower_name: repo2
   name: repo2
   default_branch: master
-  num_watches: 0
+  num_watches: 1
   num_stars: 1
   num_forks: 0
   num_issues: 2

models/fixtures/watch.yml

@@ -27,3 +27,9 @@
   user_id: 11
   repo_id: 1
   mode: 3 # auto
+
+-
+  id: 6
+  user_id: 4
+  repo_id: 2
+  mode: 1 # normal

models/forgejo_migrations/migrate.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"os"
 
+	forgejo_v1_20 "code.gitea.io/gitea/models/forgejo_migrations/v1_20"
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
@@ -34,7 +35,9 @@ func NewMigration(desc string, fn func(*xorm.Engine) error) *Migration {
 
 // This is a sequence of additional Forgejo migrations.
 // Add new migrations to the bottom of the list.
-var migrations = []*Migration{}
+var migrations = []*Migration{
+	NewMigration("Add Forgejo Blocked Users table", forgejo_v1_20.AddForgejoBlockedUser),
+}
 
 // GetCurrentDBVersion returns the current Forgejo database version.
 func GetCurrentDBVersion(x *xorm.Engine) (int64, error) {

models/forgejo_migrations/v1_20/v1.go

@@ -0,0 +1,21 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package forgejo_v1_20 //nolint:revive
+
+import (
+	"code.gitea.io/gitea/modules/timeutil"
+
+	"xorm.io/xorm"
+)
+
+func AddForgejoBlockedUser(x *xorm.Engine) error {
+	type ForgejoBlockedUser struct {
+		ID          int64              `xorm:"pk autoincr"`
+		BlockID     int64              `xorm:"index"`
+		UserID      int64              `xorm:"index"`
+		CreatedUnix timeutil.TimeStamp `xorm:"created"`
+	}
+
+	return x.Sync(new(ForgejoBlockedUser))
+}

models/issues/issue_test.go

@@ -429,6 +429,8 @@ func TestIssue_ResolveMentions(t *testing.T) {
 	testSuccess("user2", "repo1", "user1", []string{"nonexisting"}, []int64{})
 	// Public repo, doer
 	testSuccess("user2", "repo1", "user1", []string{"user1"}, []int64{})
+	// Public repo, blocked user
+	testSuccess("user2", "repo1", "user1", []string{"user4"}, []int64{})
 	// Private repo, team member
 	testSuccess("user17", "big_test_private_4", "user20", []string{"user2"}, []int64{2})
 	// Private repo, not a team member

models/issues/issue_update.go

@@ -608,9 +608,11 @@ func ResolveIssueMentionsByVisibility(ctx context.Context, issue *Issue, doer *u
 				teamusers := make([]*user_model.User, 0, 20)
 				if err := db.GetEngine(ctx).
 					Join("INNER", "team_user", "team_user.uid = `user`.id").
+					Join("LEFT", "forgejo_blocked_user", "forgejo_blocked_user.user_id = `user`.id").
 					In("`team_user`.team_id", checked).
 					And("`user`.is_active = ?", true).
 					And("`user`.prohibit_login = ?", false).
+					And(builder.Or(builder.IsNull{"`forgejo_blocked_user`.block_id"}, builder.Neq{"`forgejo_blocked_user`.block_id": doer.ID})).
 					Find(&teamusers); err != nil {
 					return nil, fmt.Errorf("get teams users: %w", err)
 				}
@@ -644,8 +646,10 @@ func ResolveIssueMentionsByVisibility(ctx context.Context, issue *Issue, doer *u
 
 	unchecked := make([]*user_model.User, 0, len(mentionUsers))
 	if err := db.GetEngine(ctx).
+		Join("LEFT", "forgejo_blocked_user", "forgejo_blocked_user.user_id = `user`.id").
 		Where("`user`.is_active = ?", true).
 		And("`user`.prohibit_login = ?", false).
+		And(builder.Or(builder.IsNull{"`forgejo_blocked_user`.block_id"}, builder.Neq{"`forgejo_blocked_user`.block_id": doer.ID})).
 		In("`user`.lower_name", mentionUsers).
 		Find(&unchecked); err != nil {
 		return nil, fmt.Errorf("find mentioned users: %w", err)

models/issues/reaction.go

@@ -218,12 +218,12 @@ type ReactionOptions struct {
 }
 
 // CreateReaction creates reaction for issue or comment.
-func CreateReaction(opts *ReactionOptions) (*Reaction, error) {
+func CreateReaction(ctx context.Context, opts *ReactionOptions) (*Reaction, error) {
 	if !setting.UI.ReactionsLookup.Contains(opts.Type) {
 		return nil, ErrForbiddenIssueReaction{opts.Type}
 	}
 
-	ctx, committer, err := db.TxContext(db.DefaultContext)
+	ctx, committer, err := db.TxContext(ctx)
 	if err != nil {
 		return nil, err
 	}
@@ -240,25 +240,6 @@ func CreateReaction(opts *ReactionOptions) (*Reaction, error) {
 	return reaction, nil
 }
 
-// CreateIssueReaction creates a reaction on issue.
-func CreateIssueReaction(doerID, issueID int64, content string) (*Reaction, error) {
-	return CreateReaction(&ReactionOptions{
-		Type:    content,
-		DoerID:  doerID,
-		IssueID: issueID,
-	})
-}
-
-// CreateCommentReaction creates a reaction on comment.
-func CreateCommentReaction(doerID, issueID, commentID int64, content string) (*Reaction, error) {
-	return CreateReaction(&ReactionOptions{
-		Type:      content,
-		DoerID:    doerID,
-		IssueID:   issueID,
-		CommentID: commentID,
-	})
-}
-
 // DeleteReaction deletes reaction for issue or comment.
 func DeleteReaction(ctx context.Context, opts *ReactionOptions) error {
 	reaction := &Reaction{

models/issues/reaction_test.go

@@ -19,11 +19,14 @@ import (
 func addReaction(t *testing.T, doerID, issueID, commentID int64, content string) {
 	var reaction *issues_model.Reaction
 	var err error
-	if commentID == 0 {
+	// NOTE: This doesn't do user blocking checking.
-		reaction, err = issues_model.CreateIssueReaction(doerID, issueID, content)
+	reaction, err = issues_model.CreateReaction(db.DefaultContext, &issues_model.ReactionOptions{
-	} else {
+		DoerID:    doerID,
-		reaction, err = issues_model.CreateCommentReaction(doerID, issueID, commentID, content)
+		IssueID:   issueID,
-	}
+		CommentID: commentID,
+		Type:      content,
+	})
+
 	assert.NoError(t, err)
 	assert.NotNil(t, reaction)
 }
@@ -49,7 +52,7 @@ func TestIssueAddDuplicateReaction(t *testing.T) {
 
 	addReaction(t, user1.ID, issue1ID, 0, "heart")
 
-	reaction, err := issues_model.CreateReaction(&issues_model.ReactionOptions{
+	reaction, err := issues_model.CreateReaction(db.DefaultContext, &issues_model.ReactionOptions{
 		DoerID:  user1.ID,
 		IssueID: issue1ID,
 		Type:    "heart",

models/repo/user_repo.go

@@ -177,3 +177,16 @@ func GetIssuePostersWithSearch(ctx context.Context, repo *Repository, isPull boo
 		Limit(30).
 		Find(&users)
 }
+
+// GetWatchedRepoIDsOwnedBy returns the repos owned by a particular user watched by a particular user
+func GetWatchedRepoIDsOwnedBy(ctx context.Context, userID, ownedByUserID int64) ([]int64, error) {
+	repoIDs := make([]int64, 0, 10)
+	err := db.GetEngine(ctx).
+		Table("repository").
+		Select("`repository`.id").
+		Join("LEFT", "watch", "`repository`.id=`watch`.repo_id").
+		Where("`watch`.user_id=?", userID).
+		And("`watch`.mode<>?", WatchModeDont).
+		And("`repository`.owner_id=?", ownedByUserID).Find(&repoIDs)
+	return repoIDs, err
+}

models/repo/user_repo_test.go

@@ -9,6 +9,7 @@ import (
 	"code.gitea.io/gitea/models/db"
 	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -71,3 +72,15 @@ func TestRepoGetReviewers(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Len(t, reviewers, 1)
 }
+
+func GetWatchedRepoIDsOwnedBy(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	user1 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 9})
+	user2 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
+
+	repoIDs, err := repo_model.GetWatchedRepoIDsOwnedBy(db.DefaultContext, user1.ID, user2.ID)
+	assert.NoError(t, err)
+	assert.Len(t, repoIDs, 1)
+	assert.EqualValues(t, 1, repoIDs[0])
+}

models/repo/watch.go

@@ -10,6 +10,8 @@ import (
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/timeutil"
+
+	"xorm.io/builder"
 )
 
 // WatchMode specifies what kind of watch the user has on a repository
@@ -142,6 +144,21 @@ func GetWatchers(ctx context.Context, repoID int64) ([]*Watch, error) {
 		Find(&watches)
 }
 
+// GetWatchersExcludeBlocked returns all watchers of given repository, whereby
+// the doer isn't blocked by one of the watchers.
+func GetWatchersExcludeBlocked(ctx context.Context, repoID, doerID int64) ([]*Watch, error) {
+	watches := make([]*Watch, 0, 10)
+	return watches, db.GetEngine(ctx).
+		Join("INNER", "`user`", "`user`.id = `watch`.user_id").
+		Join("LEFT", "forgejo_blocked_user", "forgejo_blocked_user.user_id = `watch`.user_id").
+		Where("`watch`.repo_id=?", repoID).
+		And("`watch`.mode<>?", WatchModeDont).
+		And("`user`.is_active=?", true).
+		And("`user`.prohibit_login=?", false).
+		And(builder.Or(builder.IsNull{"`forgejo_blocked_user`.block_id"}, builder.Neq{"`forgejo_blocked_user`.block_id": doerID})).
+		Find(&watches)
+}
+
 // GetRepoWatchersIDs returns IDs of watchers for a given repo ID
 // but avoids joining with `user` for performance reasons
 // User permissions must be verified elsewhere if required
@@ -184,3 +201,9 @@ func WatchIfAuto(ctx context.Context, userID, repoID int64, isWrite bool) error
 	}
 	return watchRepoMode(ctx, watch, WatchModeAuto)
 }
+
+// UnwatchRepos will unwatch the user from all given repositories.
+func UnwatchRepos(ctx context.Context, userID int64, repoIDs []int64) error {
+	_, err := db.GetEngine(ctx).Where("user_id=?", userID).In("repo_id", repoIDs).Delete(&Watch{})
+	return err
+}

models/repo/watch_test.go

@@ -43,6 +43,24 @@ func TestGetWatchers(t *testing.T) {
 	assert.Len(t, watches, 0)
 }
 
+func TestGetWatchersExcludeBlocked(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 1})
+	watches, err := repo_model.GetWatchersExcludeBlocked(db.DefaultContext, repo.ID, 1)
+	assert.NoError(t, err)
+
+	// One watchers are inactive and one watcher is blocked, thus minus 2
+	assert.Len(t, watches, repo.NumWatches-2)
+	for _, watch := range watches {
+		assert.EqualValues(t, repo.ID, watch.RepoID)
+	}
+
+	watches, err = repo_model.GetWatchersExcludeBlocked(db.DefaultContext, unittest.NonexistentID, 1)
+	assert.NoError(t, err)
+	assert.Len(t, watches, 0)
+}
+
 func TestRepository_GetWatchers(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 
@@ -137,3 +155,16 @@ func TestWatchRepoMode(t *testing.T) {
 	assert.NoError(t, repo_model.WatchRepoMode(12, 1, repo_model.WatchModeNone))
 	unittest.AssertCount(t, &repo_model.Watch{UserID: 12, RepoID: 1}, 0)
 }
+
+func TestUnwatchRepos(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	unittest.AssertExistsAndLoadBean(t, &repo_model.Watch{UserID: 4, RepoID: 1})
+	unittest.AssertExistsAndLoadBean(t, &repo_model.Watch{UserID: 4, RepoID: 2})
+
+	err := repo_model.UnwatchRepos(db.DefaultContext, 4, []int64{1, 2})
+	assert.NoError(t, err)
+
+	unittest.AssertNotExistsBean(t, &repo_model.Watch{UserID: 4, RepoID: 1})
+	unittest.AssertNotExistsBean(t, &repo_model.Watch{UserID: 4, RepoID: 2})
+}

models/user/block.go

@@ -0,0 +1,91 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package user
+
+import (
+	"context"
+	"errors"
+
+	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/modules/timeutil"
+)
+
+// ErrBlockedByUser defines an error stating that the user is not allowed to perform the action because they are blocked.
+var ErrBlockedByUser = errors.New("user is blocked by the poster or repository owner")
+
+// BlockedUser represents a blocked user entry.
+type BlockedUser struct {
+	ID int64 `xorm:"pk autoincr"`
+	// UID of the one who got blocked.
+	BlockID int64 `xorm:"index"`
+	// UID of the one who did the block action.
+	UserID int64 `xorm:"index"`
+
+	CreatedUnix timeutil.TimeStamp `xorm:"created"`
+}
+
+// TableName provides the real table name
+func (*BlockedUser) TableName() string {
+	return "forgejo_blocked_user"
+}
+
+func init() {
+	db.RegisterModel(new(BlockedUser))
+}
+
+// IsBlocked returns if userID has blocked blockID.
+func IsBlocked(ctx context.Context, userID, blockID int64) bool {
+	has, _ := db.GetEngine(ctx).Exist(&BlockedUser{UserID: userID, BlockID: blockID})
+	return has
+}
+
+// IsBlockedMultiple returns if one of the userIDs has blocked blockID.
+func IsBlockedMultiple(ctx context.Context, userIDs []int64, blockID int64) bool {
+	has, _ := db.GetEngine(ctx).In("user_id", userIDs).Exist(&BlockedUser{BlockID: blockID})
+	return has
+}
+
+// UnblockUser removes the blocked user entry.
+func UnblockUser(ctx context.Context, userID, blockID int64) error {
+	_, err := db.GetEngine(ctx).Delete(&BlockedUser{UserID: userID, BlockID: blockID})
+	return err
+}
+
+// CountBlockedUsers returns the number of users the user has blocked.
+func CountBlockedUsers(ctx context.Context, userID int64) (int64, error) {
+	return db.GetEngine(ctx).Where("user_id=?", userID).Count(&BlockedUser{})
+}
+
+// ListBlockedUsers returns the users that the user has blocked.
+// The created_unix field of the user struct is overridden by the creation_unix
+// field of blockeduser.
+func ListBlockedUsers(ctx context.Context, userID int64, opts db.ListOptions) ([]*User, error) {
+	sess := db.GetEngine(ctx).
+		Select("`forgejo_blocked_user`.created_unix, `user`.*").
+		Join("INNER", "forgejo_blocked_user", "`user`.id=`forgejo_blocked_user`.block_id").
+		Where("`forgejo_blocked_user`.user_id=?", userID)
+
+	if opts.Page > 0 {
+		sess = db.SetSessionPagination(sess, &opts)
+		users := make([]*User, 0, opts.PageSize)
+
+		return users, sess.Find(&users)
+	}
+
+	users := make([]*User, 0, 8)
+	return users, sess.Find(&users)
+}
+
+// ListBlockedByUsersID returns the ids of the users that blocked the user.
+func ListBlockedByUsersID(ctx context.Context, userID int64) ([]int64, error) {
+	users := make([]int64, 0, 8)
+	err := db.GetEngine(ctx).
+		Table("user").
+		Select("`user`.id").
+		Join("INNER", "forgejo_blocked_user", "`user`.id=`forgejo_blocked_user`.user_id").
+		Where("`forgejo_blocked_user`.block_id=?", userID).
+		Find(&users)
+
+	return users, err
+}

models/user/block_test.go

@@ -0,0 +1,77 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package user_test
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestIsBlocked(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+	assert.True(t, user_model.IsBlocked(db.DefaultContext, 4, 1))
+
+	// Simple test cases to ensure the function can also respond with false.
+	assert.False(t, user_model.IsBlocked(db.DefaultContext, 1, 1))
+	assert.False(t, user_model.IsBlocked(db.DefaultContext, 3, 2))
+}
+
+func TestIsBlockedMultiple(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+	assert.True(t, user_model.IsBlockedMultiple(db.DefaultContext, []int64{4}, 1))
+	assert.True(t, user_model.IsBlockedMultiple(db.DefaultContext, []int64{4, 3, 4, 5}, 1))
+
+	// Simple test cases to ensure the function can also respond with false.
+	assert.False(t, user_model.IsBlockedMultiple(db.DefaultContext, []int64{1}, 1))
+	assert.False(t, user_model.IsBlockedMultiple(db.DefaultContext, []int64{3, 4, 1}, 2))
+}
+
+func TestUnblockUser(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+	assert.True(t, user_model.IsBlocked(db.DefaultContext, 4, 1))
+
+	assert.NoError(t, user_model.UnblockUser(db.DefaultContext, 4, 1))
+
+	// Simple test cases to ensure the function can also respond with false.
+	assert.False(t, user_model.IsBlocked(db.DefaultContext, 4, 1))
+}
+
+func TestListBlockedUsers(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	blockedUsers, err := user_model.ListBlockedUsers(db.DefaultContext, 4, db.ListOptions{})
+	assert.NoError(t, err)
+	if assert.Len(t, blockedUsers, 1) {
+		assert.EqualValues(t, 1, blockedUsers[0].ID)
+		// The function returns the created Unix of the block, not that of the user.
+		assert.EqualValues(t, 1671607299, blockedUsers[0].CreatedUnix)
+	}
+}
+
+func TestListBlockedByUsersID(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	blockedByUserIDs, err := user_model.ListBlockedByUsersID(db.DefaultContext, 1)
+	assert.NoError(t, err)
+	if assert.Len(t, blockedByUserIDs, 1) {
+		assert.EqualValues(t, 4, blockedByUserIDs[0])
+	}
+}
+
+func TestCountBlockedUsers(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	count, err := user_model.CountBlockedUsers(db.DefaultContext, 4)
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, count)
+
+	count, err = user_model.CountBlockedUsers(db.DefaultContext, 1)
+	assert.NoError(t, err)
+	assert.EqualValues(t, 0, count)
+}

models/user/follow.go

@@ -4,6 +4,8 @@
 package user
 
 import (
+	"context"
+
 	"code.gitea.io/gitea/models/db"
 	"code.gitea.io/gitea/modules/timeutil"
 )
@@ -22,17 +24,26 @@ func init() {
 
 // IsFollowing returns true if user is following followID.
 func IsFollowing(userID, followID int64) bool {
-	has, _ := db.GetEngine(db.DefaultContext).Get(&Follow{UserID: userID, FollowID: followID})
+	return IsFollowingCtx(db.DefaultContext, userID, followID)
+}
+
+// IsFollowingCtx returns true if user is following followID.
+func IsFollowingCtx(ctx context.Context, userID, followID int64) bool {
+	has, _ := db.GetEngine(ctx).Get(&Follow{UserID: userID, FollowID: followID})
 	return has
 }
 
 // FollowUser marks someone be another's follower.
-func FollowUser(userID, followID int64) (err error) {
+func FollowUser(ctx context.Context, userID, followID int64) (err error) {
-	if userID == followID || IsFollowing(userID, followID) {
+	if userID == followID || IsFollowingCtx(ctx, userID, followID) {
 		return nil
 	}
 
-	ctx, committer, err := db.TxContext(db.DefaultContext)
+	if IsBlocked(ctx, userID, followID) || IsBlocked(ctx, followID, userID) {
+		return ErrBlockedByUser
+	}
+
+	ctx, committer, err := db.TxContext(ctx)
 	if err != nil {
 		return err
 	}
@@ -53,12 +64,12 @@ func FollowUser(userID, followID int64) (err error) {
 }
 
 // UnfollowUser unmarks someone as another's follower.
-func UnfollowUser(userID, followID int64) (err error) {
+func UnfollowUser(ctx context.Context, userID, followID int64) (err error) {
-	if userID == followID || !IsFollowing(userID, followID) {
+	if userID == followID || !IsFollowingCtx(ctx, userID, followID) {
 		return nil
 	}
 
-	ctx, committer, err := db.TxContext(db.DefaultContext)
+	ctx, committer, err := db.TxContext(ctx)
 	if err != nil {
 		return err
 	}

models/user/user_test.go

@@ -449,13 +449,19 @@ func TestFollowUser(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 
 	testSuccess := func(followerID, followedID int64) {
-		assert.NoError(t, user_model.FollowUser(followerID, followedID))
+		assert.NoError(t, user_model.FollowUser(db.DefaultContext, followerID, followedID))
 		unittest.AssertExistsAndLoadBean(t, &user_model.Follow{UserID: followerID, FollowID: followedID})
 	}
 	testSuccess(4, 2)
 	testSuccess(5, 2)
 
-	assert.NoError(t, user_model.FollowUser(2, 2))
+	assert.NoError(t, user_model.FollowUser(db.DefaultContext, 2, 2))
+
+	// Blocked user.
+	assert.ErrorIs(t, user_model.ErrBlockedByUser, user_model.FollowUser(db.DefaultContext, 1, 4))
+	assert.ErrorIs(t, user_model.ErrBlockedByUser, user_model.FollowUser(db.DefaultContext, 4, 1))
+	unittest.AssertNotExistsBean(t, &user_model.Follow{UserID: 1, FollowID: 4})
+	unittest.AssertNotExistsBean(t, &user_model.Follow{UserID: 4, FollowID: 1})
 
 	unittest.CheckConsistencyFor(t, &user_model.User{})
 }
@@ -464,7 +470,7 @@ func TestUnfollowUser(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 
 	testSuccess := func(followerID, followedID int64) {
-		assert.NoError(t, user_model.UnfollowUser(followerID, followedID))
+		assert.NoError(t, user_model.UnfollowUser(db.DefaultContext, followerID, followedID))
 		unittest.AssertNotExistsBean(t, &user_model.Follow{UserID: followerID, FollowID: followedID})
 	}
 	testSuccess(4, 2)

modules/repository/collaborator.go

@@ -14,6 +14,10 @@ import (
 )
 
 func AddCollaborator(ctx context.Context, repo *repo_model.Repository, u *user_model.User) error {
+	if user_model.IsBlocked(ctx, repo.OwnerID, u.ID) || user_model.IsBlocked(ctx, u.ID, repo.OwnerID) {
+		return user_model.ErrBlockedByUser
+	}
+
 	return db.WithTx(ctx, func(ctx context.Context) error {
 		collaboration := &repo_model.Collaboration{
 			RepoID: repo.ID,

modules/repository/collaborator_test.go

@@ -33,6 +33,33 @@ func TestRepository_AddCollaborator(t *testing.T) {
 	testSuccess(3, 4)
 }
 
+func TestRepository_AddCollaborator_IsBlocked(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	testSuccess := func(repoID, userID int64) {
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: repoID})
+		assert.NoError(t, repo.LoadOwner(db.DefaultContext))
+		user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: userID})
+
+		// Owner blocked user.
+		unittest.AssertSuccessfulInsert(t, &user_model.BlockedUser{UserID: repo.OwnerID, BlockID: userID})
+		assert.ErrorIs(t, AddCollaborator(db.DefaultContext, repo, user), user_model.ErrBlockedByUser)
+		unittest.CheckConsistencyFor(t, &repo_model.Repository{ID: repoID}, &user_model.User{ID: userID})
+		_, err := db.DeleteByBean(db.DefaultContext, &user_model.BlockedUser{UserID: repo.OwnerID, BlockID: userID})
+		assert.NoError(t, err)
+
+		// User has owner blocked.
+		unittest.AssertSuccessfulInsert(t, &user_model.BlockedUser{UserID: userID, BlockID: repo.OwnerID})
+		assert.ErrorIs(t, AddCollaborator(db.DefaultContext, repo, user), user_model.ErrBlockedByUser)
+		unittest.CheckConsistencyFor(t, &repo_model.Repository{ID: repoID}, &user_model.User{ID: userID})
+	}
+	// Ensure idempotency (public repository).
+	testSuccess(1, 4)
+	testSuccess(1, 4)
+	// Add collaborator to private repository.
+	testSuccess(3, 4)
+}
+
 func TestRepoPermissionPublicNonOrgRepo(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 

modules/structs/moderation.go

@@ -0,0 +1,13 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package structs
+
+import "time"
+
+// BlockedUser represents a blocked user.
+type BlockedUser struct {
+	BlockID int64 `json:"block_id"`
+	// swagger:strfmt date-time
+	Created time.Time `json:"created_at"`
+}

options/locale/locale_en-US.ini

@@ -588,6 +588,12 @@ joined_on = Joined on %s
 repositories = Repositories
 activity = Public Activity
 followers = Followers
+block_user = Block User
+block_user.detail = Please understand that if you block this user, other actions will be taken. Such as:
+block_user.detail_1 = You are being unfollowed from this user.
+block_user.detail_2 = This user cannot interact with your repositories, created issues and comments.
+block_user.detail_3 = This user cannot add you as a collaborator, nor can you add them as a collaborator.
+follow_blocked_user = You cannot follow this user because you have blocked this user or this user has blocked you.
 starred = Starred Repositories
 watched = Watched Repositories
 code = Code
@@ -596,6 +602,8 @@ overview = Overview
 following = Following
 follow = Follow
 unfollow = Unfollow
+block = Block
+unblock = Unblock
 heatmap.loading = Loading Heatmap…
 user_bio = Biography
 disabled_public_activity = This user has disabled the public visibility of the activity.
@@ -625,6 +633,7 @@ account_link = Linked Accounts
 organization = Organizations
 uid = Uid
 webauthn = Security Keys
+blocked_users = Blocked Users
 
 public_profile = Public Profile
 biography_placeholder = Tell us a little bit about yourself
@@ -893,6 +902,7 @@ hooks.desc = Add webhooks which will be triggered for <strong>all repositories</
 
 orgs_none = You are not a member of any organizations.
 repos_none = You do not own any repositories
+blocked_users_none = You haven't blocked any users.
 
 delete_account = Delete Your Account
 delete_prompt = This operation will permanently delete your user account. It <strong>CANNOT</strong> be undone.
@@ -915,6 +925,10 @@ visibility.limited_tooltip = Visible to authenticated users only
 visibility.private = Private
 visibility.private_tooltip = Visible only to organization members
 
+blocked_since = Blocked since %s
+user_unblock_success = The user has been unblocked successfully.
+user_block_success = The user has been blocked successfully.
+
 [repo]
 new_repo_helper = A repository contains all project files, including revision history.  Already have it elsewhere? <a href="%s">Migrate repository.</a>
 owner = Owner
@@ -1641,6 +1655,7 @@ issues.content_history.delete_from_history = Delete from history
 issues.content_history.delete_from_history_confirm = Delete from history?
 issues.content_history.options = Options
 issues.reference_link = Reference: %s
+issues.blocked_by_user = You cannot create a issue on this repository because you are blocked by the repository owner.
 
 compare.compare_base = base
 compare.compare_head = compare
@@ -1720,6 +1735,7 @@ pulls.reject_count_n = "%d change requests"
 pulls.waiting_count_1 = "%d waiting review"
 pulls.waiting_count_n = "%d waiting reviews"
 pulls.wrong_commit_id = "commit id must be a commit id on the target branch"
+pulls.blocked_by_user = You cannot create a pull request on this repository because you are blocked by the repository owner.
 
 pulls.no_merge_desc = This pull request cannot be merged because all repository merge options are disabled.
 pulls.no_merge_helper = Enable merge options in the repository settings or merge the pull request manually.
@@ -2077,6 +2093,8 @@ settings.add_collaborator_success = The collaborator has been added.
 settings.add_collaborator_inactive_user = Cannot add an inactive user as a collaborator.
 settings.add_collaborator_owner = Cannot add an owner as a collaborator.
 settings.add_collaborator_duplicate = The collaborator is already added to this repository.
+settings.add_collaborator_blocked_our = Cannot add the collaborator, because the repository owner has blocked them.
+settings.add_collaborator_blocked_them = Cannot add the collaborator, because they have blocked the repository owner.
 settings.delete_collaborator = Remove
 settings.collaborator_deletion = Remove Collaborator
 settings.collaborator_deletion_desc = Removing a collaborator will revoke their access to this repository. Continue?
@@ -2536,6 +2554,7 @@ team_access_desc = Repository access
 team_permission_desc = Permission
 team_unit_desc = Allow Access to Repository Sections
 team_unit_disabled = (Disabled)
+follow_blocked_user = You cannot follow this organisation because this organisation has blocked you.
 
 form.name_reserved = The organization name "%s" is reserved.
 form.name_pattern_not_allowed = The pattern "%s" is not allowed in an organization name.

routers/api/v1/api.go

@@ -900,6 +900,12 @@ func Routes() *web.Route {
 					Delete(user.DeleteHook)
 			}, reqWebhooksEnabled())
 
+			m.Group("", func() {
+				m.Get("/list_blocked", user.ListBlockedUsers)
+				m.Put("/block/{username}", user.BlockUser)
+				m.Put("/unblock/{username}", user.UnblockUser)
+			})
+
 			m.Group("/avatar", func() {
 				m.Post("", bind(api.UpdateUserAvatarOption{}), user.UpdateAvatar)
 				m.Delete("", user.DeleteAvatar)
@@ -1328,6 +1334,12 @@ func Routes() *web.Route {
 				m.Delete("", org.DeleteAvatar)
 			}, reqToken(), reqOrgOwnership())
 			m.Get("/activities/feeds", org.ListOrgActivityFeeds)
+
+			m.Group("", func() {
+				m.Get("/list_blocked", reqToken(), reqOrgOwnership(), org.ListBlockedUsers)
+				m.Put("/block/{username}", reqToken(), reqOrgOwnership(), org.BlockUser)
+				m.Put("/unblock/{username}", reqToken(), reqOrgOwnership(), org.UnblockUser)
+			}, reqToken(), reqOrgOwnership())
 		}, tokenRequiresScopes(auth_model.AccessTokenScopeCategoryOrganization), orgAssignment(true))
 		m.Group("/teams/{teamid}", func() {
 			m.Combo("").Get(reqToken(), org.GetTeam).

routers/api/v1/org/org.go

@@ -447,3 +447,95 @@ func ListOrgActivityFeeds(ctx *context.APIContext) {
 
 	ctx.JSON(http.StatusOK, convert.ToActivities(ctx, feeds, ctx.Doer))
 }
+
+// ListBlockedUsers list the organization's blocked users.
+func ListBlockedUsers(ctx *context.APIContext) {
+	// swagger:operation GET /orgs/{org}/list_blocked organization orgListBlockedUsers
+	// ---
+	// summary: List the organization's blocked users
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: org
+	//   in: path
+	//   description: name of the org
+	//   type: string
+	//   required: true
+	// - name: page
+	//   in: query
+	//   description: page number of results to return (1-based)
+	//   type: integer
+	// - name: limit
+	//   in: query
+	//   description: page size of results
+	//   type: integer
+	// responses:
+	//   "200":
+	//     "$ref": "#/responses/BlockedUserList"
+
+	utils.ListUserBlockedUsers(ctx, ctx.ContextUser)
+}
+
+// BlockUser blocks a user from the organization.
+func BlockUser(ctx *context.APIContext) {
+	// swagger:operation PUT /orgs/{org}/block/{username} organization orgBlockUser
+	// ---
+	// summary: Blocks a user from the organization
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: org
+	//   in: path
+	//   description: name of the org
+	//   type: string
+	//   required: true
+	// - name: username
+	//   in: path
+	//   description: username of the user
+	//   type: string
+	//   required: true
+	// responses:
+	//   "204":
+	//     "$ref": "#/responses/empty"
+	//   "404":
+	//     "$ref": "#/responses/notFound"
+
+	user := user.GetUserByParams(ctx)
+	if ctx.Written() {
+		return
+	}
+
+	utils.BlockUser(ctx, ctx.Org.Organization.AsUser(), user)
+}
+
+// UnblockUser unblocks a user from the organization.
+func UnblockUser(ctx *context.APIContext) {
+	// swagger:operation PUT /orgs/{org}/unblock/{username} organization orgUnblockUser
+	// ---
+	// summary: Unblock a user from the organization
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: org
+	//   in: path
+	//   description: name of the org
+	//   type: string
+	//   required: true
+	// - name: username
+	//   in: path
+	//   description: username of the user
+	//   type: string
+	//   required: true
+	// responses:
+	//   "204":
+	//     "$ref": "#/responses/empty"
+	//   "404":
+	//     "$ref": "#/responses/notFound"
+
+	user := user.GetUserByParams(ctx)
+	if ctx.Written() {
+		return
+	}
+
+	utils.UnblockUser(ctx, ctx.Org.Organization.AsUser(), user)
+}

routers/api/v1/repo/collaborators.go

@@ -156,6 +156,8 @@ func AddCollaborator(ctx *context.APIContext) {
 	//     "$ref": "#/responses/empty"
 	//   "422":
 	//     "$ref": "#/responses/validationError"
+	//   "403":
+	//     "$ref": "#/responses/forbidden"
 
 	form := web.GetForm(ctx).(*api.AddCollaboratorOption)
 
@@ -175,7 +177,11 @@ func AddCollaborator(ctx *context.APIContext) {
 	}
 
 	if err := repo_module.AddCollaborator(ctx, ctx.Repo.Repository, collaborator); err != nil {
+		if errors.Is(err, user_model.ErrBlockedByUser) {
+			ctx.Error(http.StatusForbidden, "AddCollaborator", err)
+		} else {
 			ctx.Error(http.StatusInternalServerError, "AddCollaborator", err)
+		}
 		return
 	}
 

routers/api/v1/repo/issue.go

@@ -5,6 +5,7 @@
 package repo
 
 import (
+	"errors"
 	"fmt"
 	"net/http"
 	"strconv"
@@ -678,7 +679,10 @@ func CreateIssue(ctx *context.APIContext) {
 	}
 
 	if err := issue_service.NewIssue(ctx, ctx.Repo.Repository, issue, form.Labels, nil, assigneeIDs); err != nil {
-		if repo_model.IsErrUserDoesNotHaveAccessToRepo(err) {
+		if errors.Is(err, user_model.ErrBlockedByUser) {
+			ctx.Error(http.StatusForbidden, "BlockedByUser", err)
+			return
+		} else if repo_model.IsErrUserDoesNotHaveAccessToRepo(err) {
 			ctx.Error(http.StatusBadRequest, "UserDoesNotHaveAccessToRepo", err)
 			return
 		}

routers/api/v1/repo/issue_comment.go

@@ -364,7 +364,11 @@ func CreateIssueComment(ctx *context.APIContext) {
 
 	comment, err := issue_service.CreateIssueComment(ctx, ctx.Doer, ctx.Repo.Repository, issue, form.Body, nil)
 	if err != nil {
+		if errors.Is(err, user_model.ErrBlockedByUser) {
+			ctx.Error(http.StatusForbidden, "CreateIssueComment", err)
+		} else {
 			ctx.Error(http.StatusInternalServerError, "CreateIssueComment", err)
+		}
 		return
 	}
 

routers/api/v1/repo/issue_reaction.go

@@ -8,11 +8,13 @@ import (
 	"net/http"
 
 	issues_model "code.gitea.io/gitea/models/issues"
+	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/context"
 	api "code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/modules/web"
 	"code.gitea.io/gitea/routers/api/v1/utils"
 	"code.gitea.io/gitea/services/convert"
+	issue_service "code.gitea.io/gitea/services/issue"
 )
 
 // GetIssueCommentReactions list reactions of a comment from an issue
@@ -196,9 +198,9 @@ func changeIssueCommentReaction(ctx *context.APIContext, form api.EditReactionOp
 
 	if isCreateType {
 		// PostIssueCommentReaction part
-		reaction, err := issues_model.CreateCommentReaction(ctx.Doer.ID, comment.Issue.ID, comment.ID, form.Reaction)
+		reaction, err := issue_service.CreateCommentReaction(ctx, ctx.Doer, comment.Issue, comment, form.Reaction)
 		if err != nil {
-			if issues_model.IsErrForbiddenIssueReaction(err) {
+			if issues_model.IsErrForbiddenIssueReaction(err) || errors.Is(err, user_model.ErrBlockedByUser) {
 				ctx.Error(http.StatusForbidden, err.Error(), err)
 			} else if issues_model.IsErrReactionAlreadyExist(err) {
 				ctx.JSON(http.StatusOK, api.Reaction{
@@ -406,9 +408,9 @@ func changeIssueReaction(ctx *context.APIContext, form api.EditReactionOption, i
 
 	if isCreateType {
 		// PostIssueReaction part
-		reaction, err := issues_model.CreateIssueReaction(ctx.Doer.ID, issue.ID, form.Reaction)
+		reaction, err := issue_service.CreateIssueReaction(ctx, ctx.Doer, issue, form.Reaction)
 		if err != nil {
-			if issues_model.IsErrForbiddenIssueReaction(err) {
+			if issues_model.IsErrForbiddenIssueReaction(err) || errors.Is(err, user_model.ErrBlockedByUser) {
 				ctx.Error(http.StatusForbidden, err.Error(), err)
 			} else if issues_model.IsErrReactionAlreadyExist(err) {
 				ctx.JSON(http.StatusOK, api.Reaction{

routers/api/v1/repo/pull.go

@@ -418,7 +418,10 @@ func CreatePullRequest(ctx *context.APIContext) {
 	}
 
 	if err := pull_service.NewPullRequest(ctx, repo, prIssue, labelIDs, []string{}, pr, assigneeIDs); err != nil {
-		if repo_model.IsErrUserDoesNotHaveAccessToRepo(err) {
+		if errors.Is(err, user_model.ErrBlockedByUser) {
+			ctx.Error(http.StatusForbidden, "BlockedByUser", err)
+			return
+		} else if repo_model.IsErrUserDoesNotHaveAccessToRepo(err) {
 			ctx.Error(http.StatusBadRequest, "UserDoesNotHaveAccessToRepo", err)
 			return
 		}

routers/api/v1/swagger/repo.go

@@ -414,3 +414,10 @@ type swaggerRepoNewIssuePinsAllowed struct {
 	// in:body
 	Body api.NewIssuePinsAllowed `json:"body"`
 }
+
+// BlockedUserList
+// swagger:response BlockedUserList
+type swaggerBlockedUserList struct {
+	// in:body
+	Body []api.BlockedUser `json:"body"`
+}

routers/api/v1/user/follower.go

@@ -5,6 +5,7 @@
 package user
 
 import (
+	"errors"
 	"net/http"
 
 	user_model "code.gitea.io/gitea/models/user"
@@ -217,8 +218,14 @@ func Follow(ctx *context.APIContext) {
 	// responses:
 	//   "204":
 	//     "$ref": "#/responses/empty"
+	//   "403":
+	//     "$ref": "#/responses/forbidden"
 
-	if err := user_model.FollowUser(ctx.Doer.ID, ctx.ContextUser.ID); err != nil {
+	if err := user_model.FollowUser(ctx, ctx.Doer.ID, ctx.ContextUser.ID); err != nil {
+		if errors.Is(err, user_model.ErrBlockedByUser) {
+			ctx.Error(http.StatusForbidden, "BlockedByUser", err)
+			return
+		}
 		ctx.Error(http.StatusInternalServerError, "FollowUser", err)
 		return
 	}
@@ -240,7 +247,7 @@ func Unfollow(ctx *context.APIContext) {
 	//   "204":
 	//     "$ref": "#/responses/empty"
 
-	if err := user_model.UnfollowUser(ctx.Doer.ID, ctx.ContextUser.ID); err != nil {
+	if err := user_model.UnfollowUser(ctx, ctx.Doer.ID, ctx.ContextUser.ID); err != nil {
 		ctx.Error(http.StatusInternalServerError, "UnfollowUser", err)
 		return
 	}

routers/api/v1/user/user.go

@@ -202,3 +202,80 @@ func ListUserActivityFeeds(ctx *context.APIContext) {
 
 	ctx.JSON(http.StatusOK, convert.ToActivities(ctx, feeds, ctx.Doer))
 }
+
+// ListBlockedUsers list the authenticated user's blocked users.
+func ListBlockedUsers(ctx *context.APIContext) {
+	// swagger:operation GET /user/list_blocked user userListBlockedUsers
+	// ---
+	// summary: List the authenticated user's blocked users
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: page
+	//   in: query
+	//   description: page number of results to return (1-based)
+	//   type: integer
+	// - name: limit
+	//   in: query
+	//   description: page size of results
+	//   type: integer
+	// responses:
+	//   "200":
+	//     "$ref": "#/responses/BlockedUserList"
+
+	utils.ListUserBlockedUsers(ctx, ctx.Doer)
+}
+
+// BlockUser blocks a user from the doer.
+func BlockUser(ctx *context.APIContext) {
+	// swagger:operation PUT /user/block/{username} user userBlockUser
+	// ---
+	// summary: Blocks a user from the doer.
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: username
+	//   in: path
+	//   description: username of the user
+	//   type: string
+	//   required: true
+	// responses:
+	//   "204":
+	//     "$ref": "#/responses/empty"
+	//   "404":
+	//     "$ref": "#/responses/notFound"
+
+	user := GetUserByParams(ctx)
+	if ctx.Written() {
+		return
+	}
+
+	utils.BlockUser(ctx, ctx.Doer, user)
+}
+
+// UnblockUser unblocks a user from the doer.
+func UnblockUser(ctx *context.APIContext) {
+	// swagger:operation PUT /user/unblock/{username} user userUnblockUser
+	// ---
+	// summary: Unblocks a user from the doer.
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: username
+	//   in: path
+	//   description: username of the user
+	//   type: string
+	//   required: true
+	// responses:
+	//   "204":
+	//     "$ref": "#/responses/empty"
+	//   "404":
+	//     "$ref": "#/responses/notFound"
+
+	user := GetUserByParams(ctx)
+	if ctx.Written() {
+		return
+	}
+
+	utils.UnblockUser(ctx, ctx.Doer, user)
+}

routers/api/v1/utils/block.go

@@ -0,0 +1,65 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package utils
+
+import (
+	"net/http"
+
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/context"
+	api "code.gitea.io/gitea/modules/structs"
+	user_service "code.gitea.io/gitea/services/user"
+)
+
+// ListUserBlockedUsers lists the blocked users of the provided doer.
+func ListUserBlockedUsers(ctx *context.APIContext, doer *user_model.User) {
+	count, err := user_model.CountBlockedUsers(ctx, doer.ID)
+	if err != nil {
+		ctx.InternalServerError(err)
+		return
+	}
+
+	blockedUsers, err := user_model.ListBlockedUsers(ctx, doer.ID, GetListOptions(ctx))
+	if err != nil {
+		ctx.InternalServerError(err)
+		return
+	}
+
+	apiBlockedUsers := make([]*api.BlockedUser, len(blockedUsers))
+	for i, blockedUser := range blockedUsers {
+		apiBlockedUsers[i] = &api.BlockedUser{
+			BlockID: blockedUser.ID,
+			Created: blockedUser.CreatedUnix.AsTime(),
+		}
+		if err != nil {
+			ctx.InternalServerError(err)
+			return
+		}
+	}
+
+	ctx.SetTotalCountHeader(count)
+	ctx.JSON(http.StatusOK, apiBlockedUsers)
+}
+
+// BlockUser blocks the blockUser from the doer.
+func BlockUser(ctx *context.APIContext, doer, blockUser *user_model.User) {
+	err := user_service.BlockUser(ctx, doer.ID, blockUser.ID)
+	if err != nil {
+		ctx.InternalServerError(err)
+		return
+	}
+
+	ctx.Status(http.StatusNoContent)
+}
+
+// UnblockUser unblocks the blockUser from the doer.
+func UnblockUser(ctx *context.APIContext, doer, blockUser *user_model.User) {
+	err := user_model.UnblockUser(ctx, doer.ID, blockUser.ID)
+	if err != nil {
+		ctx.InternalServerError(err)
+		return
+	}
+
+	ctx.Status(http.StatusNoContent)
+}

routers/web/org/setting/blocked_users.go

@@ -0,0 +1,62 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package setting
+
+import (
+	"net/http"
+	"strings"
+
+	"code.gitea.io/gitea/models/db"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/routers/utils"
+	user_service "code.gitea.io/gitea/services/user"
+)
+
+const tplBlockedUsers = "org/settings/blocked_users"
+
+// BlockedUsers renders the blocked users page.
+func BlockedUsers(ctx *context.Context) {
+	ctx.Data["Title"] = ctx.Tr("settings.blocked_users")
+	ctx.Data["PageIsSettingsBlockedUsers"] = true
+
+	blockedUsers, err := user_model.ListBlockedUsers(ctx, ctx.Org.Organization.ID, db.ListOptions{})
+	if err != nil {
+		ctx.ServerError("ListBlockedUsers", err)
+		return
+	}
+
+	ctx.Data["BlockedUsers"] = blockedUsers
+
+	ctx.HTML(http.StatusOK, tplBlockedUsers)
+}
+
+// BlockedUsersBlock blocks a particular user from the organization.
+func BlockedUsersBlock(ctx *context.Context) {
+	uname := utils.RemoveUsernameParameterSuffix(strings.ToLower(ctx.FormString("uname")))
+	u, err := user_model.GetUserByName(ctx, uname)
+	if err != nil {
+		ctx.ServerError("GetUserByName", err)
+		return
+	}
+
+	if err := user_service.BlockUser(ctx, ctx.Org.Organization.ID, u.ID); err != nil {
+		ctx.ServerError("BlockUser", err)
+		return
+	}
+
+	ctx.Flash.Success(ctx.Tr("settings.user_block_success"))
+	ctx.Redirect(ctx.Org.OrgLink + "/settings/blocked_users")
+}
+
+// BlockedUsersUnblock unblocks a particular user from the organization.
+func BlockedUsersUnblock(ctx *context.Context) {
+	if err := user_model.UnblockUser(ctx, ctx.Org.Organization.ID, ctx.FormInt64("user_id")); err != nil {
+		ctx.ServerError("BlockUser", err)
+		return
+	}
+
+	ctx.Flash.Success(ctx.Tr("settings.user_unblock_success"))
+	ctx.Redirect(ctx.Org.OrgLink + "/settings/blocked_users")
+}

routers/web/repo/issue.go

@@ -1199,7 +1199,10 @@ func NewIssuePost(ctx *context.Context) {
 	}
 
 	if err := issue_service.NewIssue(ctx, repo, issue, labelIDs, attachments, assigneeIDs); err != nil {
-		if repo_model.IsErrUserDoesNotHaveAccessToRepo(err) {
+		if errors.Is(err, user_model.ErrBlockedByUser) {
+			ctx.RenderWithErr(ctx.Tr("repo.issues.blocked_by_user"), tplIssueNew, form)
+			return
+		} else if repo_model.IsErrUserDoesNotHaveAccessToRepo(err) {
 			ctx.Error(http.StatusBadRequest, "UserDoesNotHaveAccessToRepo", err.Error())
 			return
 		}
@@ -3164,7 +3167,7 @@ func ChangeIssueReaction(ctx *context.Context) {
 
 	switch ctx.Params(":action") {
 	case "react":
-		reaction, err := issues_model.CreateIssueReaction(ctx.Doer.ID, issue.ID, form.Content)
+		reaction, err := issue_service.CreateIssueReaction(ctx, ctx.Doer, issue, form.Content)
 		if err != nil {
 			if issues_model.IsErrForbiddenIssueReaction(err) {
 				ctx.ServerError("ChangeIssueReaction", err)
@@ -3266,7 +3269,7 @@ func ChangeCommentReaction(ctx *context.Context) {
 
 	switch ctx.Params(":action") {
 	case "react":
-		reaction, err := issues_model.CreateCommentReaction(ctx.Doer.ID, comment.Issue.ID, comment.ID, form.Content)
+		reaction, err := issue_service.CreateCommentReaction(ctx, ctx.Doer, comment.Issue, comment, form.Content)
 		if err != nil {
 			if issues_model.IsErrForbiddenIssueReaction(err) {
 				ctx.ServerError("ChangeIssueReaction", err)

routers/web/repo/pull.go

@@ -1414,7 +1414,11 @@ func CompareAndPullRequestPost(ctx *context.Context) {
 	// instead of 500.
 
 	if err := pull_service.NewPullRequest(ctx, repo, pullIssue, labelIDs, attachments, pullRequest, assigneeIDs); err != nil {
-		if repo_model.IsErrUserDoesNotHaveAccessToRepo(err) {
+		if errors.Is(err, user_model.ErrBlockedByUser) {
+			ctx.Flash.Error(ctx.Tr("repo.pulls.blocked_by_user"))
+			ctx.Redirect(ctx.Link)
+			return
+		} else if repo_model.IsErrUserDoesNotHaveAccessToRepo(err) {
 			ctx.Error(http.StatusBadRequest, "UserDoesNotHaveAccessToRepo", err.Error())
 			return
 		} else if git.IsErrPushRejected(err) {

routers/web/repo/setting/collaboration.go

@@ -4,6 +4,7 @@
 package setting
 
 import (
+	"errors"
 	"net/http"
 	"strings"
 
@@ -102,10 +103,21 @@ func CollaborationPost(ctx *context.Context) {
 	}
 
 	if err = repo_module.AddCollaborator(ctx, ctx.Repo.Repository, u); err != nil {
+		if !errors.Is(err, user_model.ErrBlockedByUser) {
 			ctx.ServerError("AddCollaborator", err)
 			return
 		}
 
+		// To give an good error message, be precise on who has blocked who.
+		if blockedOurs := user_model.IsBlocked(ctx, ctx.Repo.Repository.OwnerID, u.ID); blockedOurs {
+			ctx.Flash.Error(ctx.Tr("repo.settings.add_collaborator_blocked_our"))
+		} else {
+			ctx.Flash.Error(ctx.Tr("repo.settings.add_collaborator_blocked_them"))
+		}
+		ctx.Redirect(ctx.Repo.RepoLink + "/settings/collaboration")
+		return
+	}
+
 	if setting.Service.EnableNotifyMail {
 		mailer.SendCollaboratorMail(u, ctx.Doer, ctx.Repo.Repository)
 	}

routers/web/repo/setting/settings_test.go

@@ -102,6 +102,7 @@ func TestCollaborationPost(t *testing.T) {
 	ctx.Req.Form.Set("collaborator", "user4")
 
 	u := &user_model.User{
+		ID:        2,
 		LowerName: "user2",
 		Type:      user_model.UserTypeIndividual,
 	}
@@ -109,6 +110,7 @@ func TestCollaborationPost(t *testing.T) {
 	re := &repo_model.Repository{
 		ID:      2,
 		Owner:   u,
+		OwnerID: u.ID,
 	}
 
 	repo := &context.Repository{
@@ -160,6 +162,7 @@ func TestCollaborationPost_AddCollaboratorTwice(t *testing.T) {
 	ctx.Req.Form.Set("collaborator", "user4")
 
 	u := &user_model.User{
+		ID:        2,
 		LowerName: "user2",
 		Type:      user_model.UserTypeIndividual,
 	}
@@ -167,6 +170,7 @@ func TestCollaborationPost_AddCollaboratorTwice(t *testing.T) {
 	re := &repo_model.Repository{
 		ID:      2,
 		Owner:   u,
+		OwnerID: u.ID,
 	}
 
 	repo := &context.Repository{

routers/web/shared/user/header.go

@@ -31,6 +31,7 @@ func PrepareContextForProfileBigAvatar(ctx *context.Context) {
 	prepareContextForCommonProfile(ctx)
 
 	ctx.Data["IsFollowing"] = ctx.Doer != nil && user_model.IsFollowing(ctx.Doer.ID, ctx.ContextUser.ID)
+	ctx.Data["IsBlocked"] = ctx.Doer != nil && user_model.IsBlocked(ctx, ctx.Doer.ID, ctx.ContextUser.ID)
 	ctx.Data["ShowUserEmail"] = setting.UI.ShowUserEmail && ctx.ContextUser.Email != "" && ctx.IsSigned && !ctx.ContextUser.KeepEmailPrivate
 
 	// Show OpenID URIs

routers/web/user/profile.go

@@ -5,6 +5,7 @@
 package user
 
 import (
+	"errors"
 	"fmt"
 	"net/http"
 	"strings"
@@ -23,6 +24,7 @@ import (
 	"code.gitea.io/gitea/routers/web/feed"
 	"code.gitea.io/gitea/routers/web/org"
 	shared_user "code.gitea.io/gitea/routers/web/shared/user"
+	user_service "code.gitea.io/gitea/services/user"
 )
 
 // OwnerProfile render profile page for a user or a organization (aka, repo owner)
@@ -284,17 +286,38 @@ func prepareUserProfileTabData(ctx *context.Context, showPrivate bool, profileGi
 // Action response for follow/unfollow user request
 func Action(ctx *context.Context) {
 	var err error
+	var redirectViaJSON bool
 	switch ctx.FormString("action") {
 	case "follow":
-		err = user_model.FollowUser(ctx.Doer.ID, ctx.ContextUser.ID)
+		err = user_model.FollowUser(ctx, ctx.Doer.ID, ctx.ContextUser.ID)
 	case "unfollow":
-		err = user_model.UnfollowUser(ctx.Doer.ID, ctx.ContextUser.ID)
+		err = user_model.UnfollowUser(ctx, ctx.Doer.ID, ctx.ContextUser.ID)
+	case "block":
+		err = user_service.BlockUser(ctx, ctx.Doer.ID, ctx.ContextUser.ID)
+		redirectViaJSON = true
+	case "unblock":
+		err = user_model.UnblockUser(ctx, ctx.Doer.ID, ctx.ContextUser.ID)
 	}
 
 	if err != nil {
+		if !errors.Is(err, user_model.ErrBlockedByUser) {
 			log.Error("Failed to apply action %q: %v", ctx.FormString("action"), err)
 			ctx.JSONError(fmt.Sprintf("Action %q failed", ctx.FormString("action")))
 			return
 		}
-	ctx.JSONOK()
+
+		if ctx.ContextUser.IsOrganization() {
+			ctx.Flash.Error(ctx.Tr("org.follow_blocked_user"))
+		} else {
+			ctx.Flash.Error(ctx.Tr("user.follow_blocked_user"))
+		}
+	}
+
+	if redirectViaJSON {
+		ctx.JSON(http.StatusOK, map[string]interface{}{
+			"redirect": ctx.ContextUser.HomeLink(),
+		})
+		return
+	}
+	ctx.RedirectToFirst(ctx.FormString("redirect_to"), ctx.ContextUser.HomeLink())
 }

routers/web/user/setting/blocked_users.go

@@ -0,0 +1,46 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package setting
+
+import (
+	"net/http"
+
+	"code.gitea.io/gitea/models/db"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/base"
+	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/setting"
+)
+
+const (
+	tplSettingsBlockedUsers base.TplName = "user/settings/blocked_users"
+)
+
+// BlockedUsers render the blocked users list page.
+func BlockedUsers(ctx *context.Context) {
+	ctx.Data["Title"] = ctx.Tr("settings.blocked_users")
+	ctx.Data["PageIsBlockedUsers"] = true
+	ctx.Data["BaseLink"] = setting.AppSubURL + "/user/settings/blocked_users"
+	ctx.Data["BaseLinkNew"] = setting.AppSubURL + "/user/settings/blocked_users"
+
+	blockedUsers, err := user_model.ListBlockedUsers(ctx, ctx.Doer.ID, db.ListOptions{})
+	if err != nil {
+		ctx.ServerError("ListBlockedUsers", err)
+		return
+	}
+
+	ctx.Data["BlockedUsers"] = blockedUsers
+	ctx.HTML(http.StatusOK, tplSettingsBlockedUsers)
+}
+
+// UnblockUser unblocks a particular user for the doer.
+func UnblockUser(ctx *context.Context) {
+	if err := user_model.UnblockUser(ctx, ctx.Doer.ID, ctx.FormInt64("user_id")); err != nil {
+		ctx.ServerError("UnblockUser", err)
+		return
+	}
+
+	ctx.Flash.Success(ctx.Tr("settings.user_unblock_success"))
+	ctx.Redirect(setting.AppSubURL + "/user/settings/blocked_users")
+}

routers/web/web.go

@@ -521,6 +521,11 @@ func registerRoutes(m *web.Route) {
 			})
 			addWebhookEditRoutes()
 		}, webhooksEnabled)
+
+		m.Group("/blocked_users", func() {
+			m.Get("", user_setting.BlockedUsers)
+			m.Post("/unblock", user_setting.UnblockUser)
+		})
 	}, reqSignIn, ctxDataSet("PageIsUserSettings", true, "AllThemes", setting.UI.Themes, "EnablePackages", setting.Packages.Enabled))
 
 	m.Group("/user", func() {
@@ -776,6 +781,12 @@ func registerRoutes(m *web.Route) {
 
 				m.Methods("GET,POST", "/delete", org.SettingsDelete)
 
+				m.Group("/blocked_users", func() {
+					m.Get("", org_setting.BlockedUsers)
+					m.Post("/block", org_setting.BlockedUsersBlock)
+					m.Post("/unblock", org_setting.BlockedUsersUnblock)
+				})
+
 				m.Group("/packages", func() {
 					m.Get("", org.Packages)
 					m.Group("/rules", func() {

services/issue/comments.go

@@ -66,6 +66,11 @@ func CreateRefComment(ctx context.Context, doer *user_model.User, repo *repo_mod
 
 // CreateIssueComment creates a plain issue comment.
 func CreateIssueComment(ctx context.Context, doer *user_model.User, repo *repo_model.Repository, issue *issues_model.Issue, content string, attachments []string) (*issues_model.Comment, error) {
+	// Check if doer is blocked by the poster of the issue.
+	if user_model.IsBlocked(ctx, issue.PosterID, doer.ID) {
+		return nil, user_model.ErrBlockedByUser
+	}
+
 	comment, err := CreateComment(ctx, &issues_model.CreateCommentOptions{
 		Type:        issues_model.CommentTypeComment,
 		Doer:        doer,

services/issue/issue.go

@@ -22,6 +22,11 @@ import (
 
 // NewIssue creates new issue with labels for repository.
 func NewIssue(ctx context.Context, repo *repo_model.Repository, issue *issues_model.Issue, labelIDs []int64, uuids []string, assigneeIDs []int64) error {
+	// Check if the user is not blocked by the repo's owner.
+	if user_model.IsBlocked(ctx, repo.OwnerID, issue.PosterID) {
+		return user_model.ErrBlockedByUser
+	}
+
 	if err := issues_model.NewIssue(repo, issue, labelIDs, uuids); err != nil {
 		return err
 	}

services/issue/reaction.go

@@ -0,0 +1,47 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+package issue
+
+import (
+	"context"
+
+	issues_model "code.gitea.io/gitea/models/issues"
+	user_model "code.gitea.io/gitea/models/user"
+)
+
+// CreateIssueReaction creates a reaction on issue.
+func CreateIssueReaction(ctx context.Context, doer *user_model.User, issue *issues_model.Issue, content string) (*issues_model.Reaction, error) {
+	if err := issue.LoadRepo(ctx); err != nil {
+		return nil, err
+	}
+
+	// Check if the doer is blocked by the issue's poster or repository owner.
+	if user_model.IsBlockedMultiple(ctx, []int64{issue.PosterID, issue.Repo.OwnerID}, doer.ID) {
+		return nil, user_model.ErrBlockedByUser
+	}
+
+	return issues_model.CreateReaction(ctx, &issues_model.ReactionOptions{
+		Type:    content,
+		DoerID:  doer.ID,
+		IssueID: issue.ID,
+	})
+}
+
+// CreateCommentReaction creates a reaction on comment.
+func CreateCommentReaction(ctx context.Context, doer *user_model.User, issue *issues_model.Issue, comment *issues_model.Comment, content string) (*issues_model.Reaction, error) {
+	if err := issue.LoadRepo(ctx); err != nil {
+		return nil, err
+	}
+
+	// Check if the doer is blocked by the issue's poster, the comment's poster or repository owner.
+	if user_model.IsBlockedMultiple(ctx, []int64{comment.PosterID, issue.PosterID, issue.Repo.OwnerID}, doer.ID) {
+		return nil, user_model.ErrBlockedByUser
+	}
+
+	return issues_model.CreateReaction(ctx, &issues_model.ReactionOptions{
+		Type:      content,
+		DoerID:    doer.ID,
+		IssueID:   issue.ID,
+		CommentID: comment.ID,
+	})
+}

services/pull/pull.go

@@ -39,6 +39,11 @@ var pullWorkingPool = sync.NewExclusivePool()
 
 // NewPullRequest creates new pull request with labels for repository.
 func NewPullRequest(ctx context.Context, repo *repo_model.Repository, pull *issues_model.Issue, labelIDs []int64, uuids []string, pr *issues_model.PullRequest, assigneeIDs []int64) error {
+	// Check if the doer is not blocked by the repository's owner.
+	if user_model.IsBlocked(ctx, repo.OwnerID, pull.PosterID) {
+		return user_model.ErrBlockedByUser
+	}
+
 	if err := TestPatch(pr); err != nil {
 		return err
 	}

services/user/block.go

@@ -0,0 +1,58 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+package user
+
+import (
+	"context"
+
+	"code.gitea.io/gitea/models/db"
+	repo_model "code.gitea.io/gitea/models/repo"
+	user_model "code.gitea.io/gitea/models/user"
+)
+
+// BlockUser adds a blocked user entry for userID to block blockID.
+// TODO: Figure out if instance admins should be immune to blocking.
+// TODO: Add more mechanism like removing blocked user as collaborator on
+// repositories where the user is an owner.
+func BlockUser(ctx context.Context, userID, blockID int64) error {
+	if userID == blockID || user_model.IsBlocked(ctx, userID, blockID) {
+		return nil
+	}
+
+	ctx, committer, err := db.TxContext(ctx)
+	if err != nil {
+		return err
+	}
+	defer committer.Close()
+
+	// Add the blocked user entry.
+	_, err = db.GetEngine(ctx).Insert(&user_model.BlockedUser{UserID: userID, BlockID: blockID})
+	if err != nil {
+		return err
+	}
+
+	// Unfollow the user from the block's perspective.
+	err = user_model.UnfollowUser(ctx, blockID, userID)
+	if err != nil {
+		return err
+	}
+
+	// Unfollow the user from the doer's perspective.
+	err = user_model.UnfollowUser(ctx, userID, blockID)
+	if err != nil {
+		return err
+	}
+
+	// Blocked user unwatch all repository owned by the doer.
+	repoIDs, err := repo_model.GetWatchedRepoIDsOwnedBy(ctx, blockID, userID)
+	if err != nil {
+		return err
+	}
+
+	err = repo_model.UnwatchRepos(ctx, blockID, repoIDs)
+	if err != nil {
+		return err
+	}
+
+	return committer.Commit()
+}

services/user/block_test.go

@@ -0,0 +1,41 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package user
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/models/db"
+	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// TestBlockUser will ensure that when you block a user, certain actions have
+// been taken, like unfollowing each other etc.
+func TestBlockUser(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	doer := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 5})
+	blockedUser := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
+
+	// Follow each other.
+	assert.NoError(t, user_model.FollowUser(db.DefaultContext, doer.ID, blockedUser.ID))
+	assert.NoError(t, user_model.FollowUser(db.DefaultContext, blockedUser.ID, doer.ID))
+
+	// Blocked user watch repository of doer.
+	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{OwnerID: doer.ID})
+	assert.NoError(t, repo_model.WatchRepo(db.DefaultContext, blockedUser.ID, repo.ID, true))
+
+	assert.NoError(t, BlockUser(db.DefaultContext, doer.ID, blockedUser.ID))
+
+	// Ensure they aren't following each other anymore.
+	assert.False(t, user_model.IsFollowing(doer.ID, blockedUser.ID))
+	assert.False(t, user_model.IsFollowing(blockedUser.ID, doer.ID))
+
+	// Ensure blocked user isn't following doer's repository.
+	assert.False(t, repo_model.IsWatching(blockedUser.ID, repo.ID))
+}

services/user/delete.go

@@ -90,6 +90,8 @@ func deleteUser(ctx context.Context, u *user_model.User, purge bool) (err error)
 		&pull_model.AutoMerge{DoerID: u.ID},
 		&pull_model.ReviewState{UserID: u.ID},
 		&user_model.Redirect{RedirectUserID: u.ID},
+		&user_model.BlockedUser{BlockID: u.ID},
+		&user_model.BlockedUser{UserID: u.ID},
 	); err != nil {
 		return fmt.Errorf("deleteBeans: %w", err)
 	}

templates/org/home.tmpl

@@ -1,5 +1,10 @@
 {{template "base/head" .}}
 <div role="main" aria-label="{{.Title}}" class="page-content organization profile">
+	{{if .Flash}}
+		<div class="ui container gt-mb-5">
+			{{template "base/alert" .}}
+		</div>
+	{{end}}
 	<div class="ui container gt-df">
 		{{avatar $.Context .Org 140 "org-avatar"}}
 		<div id="org-info">

templates/org/settings/blocked_users.tmpl

@@ -0,0 +1,40 @@
+{{template "org/settings/layout_head" (dict "ctxData" . "pageClass" "organization settings blocked-users")}}
+<div class="org-setting-content">
+	<div class="ui attached segment">
+		<form class="ui form ignore-dirty gt-df gt-fw gt-gap-3" action="{{$.Link}}/block" method="post">
+			{{.CsrfTokenHtml}}
+			<input type="hidden" name="uid" value="">
+			<div class="ui left">
+				<div id="search-user-box" class="ui search">
+					<div class="ui input">
+						<input class="prompt" name="uname" placeholder="{{.locale.Tr "repo.settings.search_user_placeholder"}}" autocomplete="off" required>
+					</div>
+				</div>
+			</div>
+			<button type="submit" class="ui red button">{{.locale.Tr "user.block"}}</button>
+		</form>
+	</div>
+	<div class="ui bottom attached table segment blocked-users">
+		{{range .BlockedUsers}}
+			<div class="item gt-df gt-ac gt-fw">
+				{{avatar $.Context . 48 "gt-mr-3 gt-mb-0"}}
+					<div class="gt-df gt-fc">
+						<a href="{{.HomeLink}}">{{.Name}}</a>
+						<i class="gt-mt-2">{{$.locale.Tr "settings.blocked_since" (DateTime "short" .CreatedUnix) | Safe}}</i>
+					</div>
+					<div class="gt-ml-auto content">
+						<form action="{{$.Link}}/unblock" method="post">
+							{{$.CsrfTokenHtml}}
+							<input type="hidden" name="user_id" value="{{.ID}}">
+							<button class="ui red button">{{$.locale.Tr "user.unblock"}}</button>
+						</form>
+					</div>
+				</div>
+			{{else}}
+				<div class="item">
+					<span class="text grey italic">{{$.locale.Tr "settings.blocked_users_none"}}</span>
+				</div>
+			{{end}}
+		</div>
+</div>
+{{template "org/settings/layout_footer" .}}

templates/org/settings/navbar.tmpl

@@ -38,6 +38,9 @@
 			</div>
 		</details>
 		{{end}}
+			<a class="{{if .PageIsSettingsBlockedUsers}}active {{end}}item" href="{{.OrgLink}}/settings/blocked_users">
+			{{.locale.Tr "settings.blocked_users"}}
+		</a>
 		<a class="{{if .PageIsSettingsDelete}}active {{end}}item" href="{{.OrgLink}}/settings/delete">
 			{{.locale.Tr "org.settings.delete"}}
 		</a>

templates/shared/user/profile_big_avatar.tmpl

@@ -117,6 +117,18 @@
 					</button>
 				{{end}}
 			</li>
+			<li class="block">
+				{{if $.IsBlocked}}
+					<button class="ui basic red button link-action" data-url="{{.ContextUser.HomeLink}}?action=unblock&redirect_to={{$.Link}}">
+						{{svg "octicon-person"}} {{.locale.Tr "user.unblock"}}
+					</button>
+				{{else}}
+					<button type="submit" class="ui basic orange button delete-button"
+					data-modal-id="block-user" data-url="{{.ContextUser.HomeLink}}?action=block">
+						{{svg "octicon-blocked"}} {{.locale.Tr "user.block"}}
+					</button>
+				{{end}}
+			</li>
 			{{end}}
 		</ul>
 	</div>

templates/swagger/v1_json.tmpl

@@ -1655,6 +1655,42 @@
         }
       }
     },
+    "/orgs/{org}/block/{username}": {
+      "put": {
+        "produces": [
+          "application/json"
+        ],
+        "tags": [
+          "organization"
+        ],
+        "summary": "Blocks a user from the organization",
+        "operationId": "orgBlockUser",
+        "parameters": [
+          {
+            "type": "string",
+            "description": "name of the org",
+            "name": "org",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "string",
+            "description": "username of the user",
+            "name": "username",
+            "in": "path",
+            "required": true
+          }
+        ],
+        "responses": {
+          "204": {
+            "$ref": "#/responses/empty"
+          },
+          "404": {
+            "$ref": "#/responses/notFound"
+          }
+        }
+      }
+    },
     "/orgs/{org}/hooks": {
       "get": {
         "produces": [
@@ -2019,6 +2055,44 @@
         }
       }
     },
+    "/orgs/{org}/list_blocked": {
+      "get": {
+        "produces": [
+          "application/json"
+        ],
+        "tags": [
+          "organization"
+        ],
+        "summary": "List the organization's blocked users",
+        "operationId": "orgListBlockedUsers",
+        "parameters": [
+          {
+            "type": "string",
+            "description": "name of the org",
+            "name": "org",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "integer",
+            "description": "page number of results to return (1-based)",
+            "name": "page",
+            "in": "query"
+          },
+          {
+            "type": "integer",
+            "description": "page size of results",
+            "name": "limit",
+            "in": "query"
+          }
+        ],
+        "responses": {
+          "200": {
+            "$ref": "#/responses/BlockedUserList"
+          }
+        }
+      }
+    },
     "/orgs/{org}/members": {
       "get": {
         "produces": [
@@ -2483,6 +2557,42 @@
         }
       }
     },
+    "/orgs/{org}/unblock/{username}": {
+      "put": {
+        "produces": [
+          "application/json"
+        ],
+        "tags": [
+          "organization"
+        ],
+        "summary": "Unblock a user from the organization",
+        "operationId": "orgUnblockUser",
+        "parameters": [
+          {
+            "type": "string",
+            "description": "name of the org",
+            "name": "org",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "string",
+            "description": "username of the user",
+            "name": "username",
+            "in": "path",
+            "required": true
+          }
+        ],
+        "responses": {
+          "204": {
+            "$ref": "#/responses/empty"
+          },
+          "404": {
+            "$ref": "#/responses/notFound"
+          }
+        }
+      }
+    },
     "/packages/{owner}": {
       "get": {
         "produces": [
@@ -3841,6 +3951,9 @@
           "204": {
             "$ref": "#/responses/empty"
           },
+          "403": {
+            "$ref": "#/responses/forbidden"
+          },
           "422": {
             "$ref": "#/responses/validationError"
           }
@@ -13962,6 +14075,35 @@
         }
       }
     },
+    "/user/block/{username}": {
+      "put": {
+        "produces": [
+          "application/json"
+        ],
+        "tags": [
+          "user"
+        ],
+        "summary": "Blocks a user from the doer.",
+        "operationId": "userBlockUser",
+        "parameters": [
+          {
+            "type": "string",
+            "description": "username of the user",
+            "name": "username",
+            "in": "path",
+            "required": true
+          }
+        ],
+        "responses": {
+          "204": {
+            "$ref": "#/responses/empty"
+          },
+          "404": {
+            "$ref": "#/responses/notFound"
+          }
+        }
+      }
+    },
     "/user/emails": {
       "get": {
         "produces": [
@@ -14138,6 +14280,9 @@
         "responses": {
           "204": {
             "$ref": "#/responses/empty"
+          },
+          "403": {
+            "$ref": "#/responses/forbidden"
           }
         }
       },
@@ -14608,6 +14753,37 @@
         }
       }
     },
+    "/user/list_blocked": {
+      "get": {
+        "produces": [
+          "application/json"
+        ],
+        "tags": [
+          "user"
+        ],
+        "summary": "List the authenticated user's blocked users",
+        "operationId": "userListBlockedUsers",
+        "parameters": [
+          {
+            "type": "integer",
+            "description": "page number of results to return (1-based)",
+            "name": "page",
+            "in": "query"
+          },
+          {
+            "type": "integer",
+            "description": "page size of results",
+            "name": "limit",
+            "in": "query"
+          }
+        ],
+        "responses": {
+          "200": {
+            "$ref": "#/responses/BlockedUserList"
+          }
+        }
+      }
+    },
     "/user/orgs": {
       "get": {
         "produces": [
@@ -15009,6 +15185,35 @@
         }
       }
     },
+    "/user/unblock/{username}": {
+      "put": {
+        "produces": [
+          "application/json"
+        ],
+        "tags": [
+          "user"
+        ],
+        "summary": "Unblocks a user from the doer.",
+        "operationId": "userUnblockUser",
+        "parameters": [
+          {
+            "type": "string",
+            "description": "username of the user",
+            "name": "username",
+            "in": "path",
+            "required": true
+          }
+        ],
+        "responses": {
+          "204": {
+            "$ref": "#/responses/empty"
+          },
+          "404": {
+            "$ref": "#/responses/notFound"
+          }
+        }
+      }
+    },
     "/users/search": {
       "get": {
         "produces": [
@@ -15939,6 +16144,23 @@
       },
       "x-go-package": "code.gitea.io/gitea/modules/structs"
     },
+    "BlockedUser": {
+      "type": "object",
+      "title": "BlockedUser represents a blocked user.",
+      "properties": {
+        "block_id": {
+          "type": "integer",
+          "format": "int64",
+          "x-go-name": "BlockID"
+        },
+        "created_at": {
+          "type": "string",
+          "format": "date-time",
+          "x-go-name": "Created"
+        }
+      },
+      "x-go-package": "code.gitea.io/gitea/modules/structs"
+    },
     "Branch": {
       "description": "Branch represents a repository branch",
       "type": "object",
@@ -22164,6 +22386,15 @@
         }
       }
     },
+    "BlockedUserList": {
+      "description": "BlockedUserList",
+      "schema": {
+        "type": "array",
+        "items": {
+          "$ref": "#/definitions/BlockedUser"
+        }
+      }
+    },
     "Branch": {
       "description": "Branch",
       "schema": {

templates/user/profile.tmpl

@@ -1,6 +1,7 @@
 {{template "base/head" .}}
 <div role="main" aria-label="{{.Title}}" class="page-content user profile">
 	<div class="ui container">
+		{{template "base/alert" .}}
 		<div class="ui stackable grid">
 			<div class="ui four wide column">
 				{{template "shared/user/profile_big_avatar" .}}
@@ -41,4 +42,20 @@
 		</div>
 	</div>
 </div>
+<div class="ui small basic delete modal" id="block-user">
+	<div class="ui icon header">
+		{{svg "octicon-blocked" 16 "blocked inside"}}
+		{{$.locale.Tr "user.block_user"}}
+	</div>
+	<div class="content">
+		<p>{{$.locale.Tr "user.block_user.detail"}}</p>
+		<ul>
+				<li>{{$.locale.Tr "user.block_user.detail_1"}}</li>
+				<li>{{$.locale.Tr "user.block_user.detail_2"}}</li>
+				<li>{{$.locale.Tr "user.block_user.detail_3"}}</li>
+		</ul>
+	</div>
+	{{template "base/modal_actions_confirm" .}}
+</div>
+
 {{template "base/footer" .}}

templates/user/settings/blocked_users.tmpl

@@ -0,0 +1,31 @@
+{{template "user/settings/layout_head" (dict "ctxData" . "pageClass" "user settings blocked_users")}}
+	<div class="user-setting-content">
+		<h4 class="ui top attached header">
+			{{.locale.Tr "settings.blocked_users"}}
+		</h4>
+		<div class="ui attached segment">
+			<div class="ui blocked-user list gt-mt-0">
+				{{range .BlockedUsers}}
+					<div class="item gt-df gt-ac">
+						{{avatar $.Context . 28 "gt-mr-3"}}
+						<div class="gt-df gt-fc">
+							<a href="{{.HomeLink}}">{{.Name}}</a>
+							<i class="gt-mt-2">{{$.locale.Tr "settings.blocked_since" (DateTime "short" .CreatedUnix) | Safe}}</i>
+						</div>
+						<div class="gt-ml-auto content">
+							<form action="{{$.Link}}/unblock" method="post">
+								{{$.CsrfTokenHtml}}
+								<input type="hidden" name="user_id" value="{{.ID}}">
+								<button class="ui red button">{{$.locale.Tr "user.unblock"}}</button>
+							</form>
+						</div>
+					</div>
+				{{else}}
+					<div class="item">
+						<span class="text grey italic">{{$.locale.Tr "settings.blocked_users_none"}}</span>
+					</div>
+				{{end}}
+			</div>
+		</div>
+	</div>
+{{template "user/settings/layout_footer" .}}

templates/user/settings/navbar.tmpl

@@ -51,5 +51,8 @@
 		<a class="{{if .PageIsSettingsRepos}}active {{end}}item" href="{{AppSubUrl}}/user/settings/repos">
 			{{.locale.Tr "settings.repos"}}
 		</a>
+		<a class="{{if .PageIsBlockedUsers}}active {{end}}item" href="{{AppSubUrl}}/user/settings/blocked_users">
+			{{.locale.Tr "settings.blocked_users"}}
+		</a>
 	</div>
 </div>

tests/integration/api_block_test.go

@@ -0,0 +1,141 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package integration
+
+import (
+	"fmt"
+	"net/http"
+	"testing"
+
+	auth_model "code.gitea.io/gitea/models/auth"
+	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+	api "code.gitea.io/gitea/modules/structs"
+	"code.gitea.io/gitea/tests"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAPIUserBlock(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	user := "user4"
+	session := loginUser(t, user)
+	token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWriteUser)
+
+	t.Run("BlockUser", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+
+		req := NewRequest(t, "PUT", fmt.Sprintf("/api/v1/user/block/user2?token=%s", token))
+		MakeRequest(t, req, http.StatusNoContent)
+
+		unittest.AssertExistsAndLoadBean(t, &user_model.BlockedUser{UserID: 4, BlockID: 2})
+	})
+
+	t.Run("ListBlocked", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+
+		req := NewRequest(t, "GET", fmt.Sprintf("/api/v1/user/list_blocked?token=%s", token))
+		resp := MakeRequest(t, req, http.StatusOK)
+
+		// One user just got blocked and the other one is defined in the fixtures.
+		assert.Equal(t, "2", resp.Header().Get("X-Total-Count"))
+
+		var blockedUsers []api.BlockedUser
+		DecodeJSON(t, resp, &blockedUsers)
+		assert.Len(t, blockedUsers, 2)
+		assert.EqualValues(t, 1, blockedUsers[0].BlockID)
+		assert.EqualValues(t, 2, blockedUsers[1].BlockID)
+	})
+
+	t.Run("UnblockUser", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+
+		req := NewRequest(t, "PUT", fmt.Sprintf("/api/v1/user/unblock/user2?token=%s", token))
+		MakeRequest(t, req, http.StatusNoContent)
+
+		unittest.AssertNotExistsBean(t, &user_model.BlockedUser{UserID: 4, BlockID: 2})
+	})
+}
+
+func TestAPIOrgBlock(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	user := "user5"
+	org := "user6"
+	session := loginUser(t, user)
+	token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWriteOrganization)
+
+	t.Run("BlockUser", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+
+		req := NewRequest(t, "PUT", fmt.Sprintf("/api/v1/orgs/%s/block/user2?token=%s", org, token))
+		MakeRequest(t, req, http.StatusNoContent)
+
+		unittest.AssertExistsAndLoadBean(t, &user_model.BlockedUser{UserID: 6, BlockID: 2})
+	})
+
+	t.Run("ListBlocked", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+
+		req := NewRequest(t, "GET", fmt.Sprintf("/api/v1/orgs/%s/list_blocked?token=%s", org, token))
+		resp := MakeRequest(t, req, http.StatusOK)
+
+		assert.Equal(t, "1", resp.Header().Get("X-Total-Count"))
+
+		var blockedUsers []api.BlockedUser
+		DecodeJSON(t, resp, &blockedUsers)
+		assert.Len(t, blockedUsers, 1)
+		assert.EqualValues(t, 2, blockedUsers[0].BlockID)
+	})
+
+	t.Run("UnblockUser", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+
+		req := NewRequest(t, "PUT", fmt.Sprintf("/api/v1/orgs/%s/unblock/user2?token=%s", org, token))
+		MakeRequest(t, req, http.StatusNoContent)
+
+		unittest.AssertNotExistsBean(t, &user_model.BlockedUser{UserID: 6, BlockID: 2})
+	})
+}
+
+// TestAPIBlock_AddCollaborator ensures that the doer and blocked user cannot
+// add each others as collaborators via the API.
+func TestAPIBlock_AddCollaborator(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	user1 := "user10"
+	user2 := "user2"
+	perm := "write"
+	collabOption := &api.AddCollaboratorOption{Permission: &perm}
+
+	// User1 blocks User2.
+	session := loginUser(t, user1)
+	token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWriteUser, auth_model.AccessTokenScopeWriteRepository)
+
+	req := NewRequest(t, "PUT", fmt.Sprintf("/api/v1/user/block/%s?token=%s", user2, token))
+	MakeRequest(t, req, http.StatusNoContent)
+	unittest.AssertExistsAndLoadBean(t, &user_model.BlockedUser{UserID: 10, BlockID: 2})
+
+	t.Run("BlockedUser Add Doer", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 2, OwnerID: 2})
+		session := loginUser(t, user2)
+		token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWriteRepository)
+
+		req := NewRequestWithJSON(t, "PUT", fmt.Sprintf("/api/v1/repos/%s/%s/collaborators/%s?token=%s", user2, repo.Name, user1, token), collabOption)
+		session.MakeRequest(t, req, http.StatusForbidden)
+	})
+
+	t.Run("Doer Add BlockedUser", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 7, OwnerID: 10})
+		session := loginUser(t, user1)
+		token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWriteRepository)
+
+		req := NewRequestWithJSON(t, "PUT", fmt.Sprintf("/api/v1/repos/%s/%s/collaborators/%s?token=%s", user1, repo.Name, user2, token), collabOption)
+		session.MakeRequest(t, req, http.StatusForbidden)
+	})
+}

tests/integration/api_user_follow_test.go

@@ -19,7 +19,7 @@ func TestAPIFollow(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()
 
 	user1 := "user4"
-	user2 := "user1"
+	user2 := "user10"
 
 	session1 := loginUser(t, user1)
 	token1 := getTokenForLoggedInUser(t, session1, auth_model.AccessTokenScopeReadUser)

tests/integration/block_test.go

@@ -0,0 +1,257 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package integration
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+	"path"
+	"strconv"
+	"testing"
+
+	"code.gitea.io/gitea/models/db"
+	issue_model "code.gitea.io/gitea/models/issues"
+	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+	forgejo_context "code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/translation"
+	"code.gitea.io/gitea/tests"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func BlockUser(t *testing.T, doer, blockedUser *user_model.User) {
+	t.Helper()
+
+	unittest.AssertNotExistsBean(t, &user_model.BlockedUser{BlockID: blockedUser.ID, UserID: doer.ID})
+
+	session := loginUser(t, doer.Name)
+	req := NewRequestWithValues(t, "POST", "/"+blockedUser.Name, map[string]string{
+		"_csrf":  GetCSRF(t, session, "/"+blockedUser.Name),
+		"action": "block",
+	})
+	resp := session.MakeRequest(t, req, http.StatusOK)
+
+	type redirect struct {
+		Redirect string `json:"redirect"`
+	}
+
+	var respBody redirect
+	DecodeJSON(t, resp, &respBody)
+	assert.EqualValues(t, "/"+blockedUser.Name, respBody.Redirect)
+	assert.True(t, unittest.BeanExists(t, &user_model.BlockedUser{BlockID: blockedUser.ID, UserID: doer.ID}))
+}
+
+func TestBlockUser(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	doer := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 8})
+	blockedUser := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
+	BlockUser(t, doer, blockedUser)
+
+	// Unblock user.
+	session := loginUser(t, doer.Name)
+	req := NewRequestWithValues(t, "POST", "/"+blockedUser.Name, map[string]string{
+		"_csrf":  GetCSRF(t, session, "/"+blockedUser.Name),
+		"action": "unblock",
+	})
+	resp := session.MakeRequest(t, req, http.StatusSeeOther)
+
+	loc := resp.Header().Get("Location")
+	assert.EqualValues(t, "/"+blockedUser.Name, loc)
+	unittest.AssertNotExistsBean(t, &user_model.BlockedUser{BlockID: blockedUser.ID, UserID: doer.ID})
+}
+
+func TestBlockIssueCreation(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	doer := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+	blockedUser := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
+	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 2, OwnerID: doer.ID})
+	BlockUser(t, doer, blockedUser)
+
+	session := loginUser(t, blockedUser.Name)
+	req := NewRequest(t, "GET", "/"+repo.OwnerName+"/"+repo.Name+"/issues/new")
+	resp := session.MakeRequest(t, req, http.StatusOK)
+
+	htmlDoc := NewHTMLParser(t, resp.Body)
+	link, exists := htmlDoc.doc.Find("form.ui.form").Attr("action")
+	assert.True(t, exists)
+	req = NewRequestWithValues(t, "POST", link, map[string]string{
+		"_csrf":   htmlDoc.GetCSRF(),
+		"title":   "Title",
+		"content": "Hello!",
+	})
+
+	resp = session.MakeRequest(t, req, http.StatusOK)
+	htmlDoc = NewHTMLParser(t, resp.Body)
+	assert.Contains(t,
+		htmlDoc.doc.Find(".ui.negative.message").Text(),
+		translation.NewLocale("en-US").Tr("repo.issues.blocked_by_user"),
+	)
+}
+
+func TestBlockIssueReaction(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	doer := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+	blockedUser := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
+	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 2})
+	issue := unittest.AssertExistsAndLoadBean(t, &issue_model.Issue{ID: 4, PosterID: doer.ID, RepoID: repo.ID})
+	issueURL := fmt.Sprintf("/%s/%s/issues/%d", url.PathEscape(repo.OwnerName), url.PathEscape(repo.Name), issue.Index)
+
+	BlockUser(t, doer, blockedUser)
+
+	session := loginUser(t, blockedUser.Name)
+	req := NewRequest(t, "GET", issueURL)
+	resp := session.MakeRequest(t, req, http.StatusOK)
+	htmlDoc := NewHTMLParser(t, resp.Body)
+
+	req = NewRequestWithValues(t, "POST", path.Join(issueURL, "/reactions/react"), map[string]string{
+		"_csrf":   htmlDoc.GetCSRF(),
+		"content": "eyes",
+	})
+	resp = session.MakeRequest(t, req, http.StatusOK)
+	type reactionResponse struct {
+		Empty bool `json:"empty"`
+	}
+
+	var respBody reactionResponse
+	DecodeJSON(t, resp, &respBody)
+
+	assert.EqualValues(t, true, respBody.Empty)
+}
+
+func TestBlockCommentReaction(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	doer := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 5})
+	blockedUser := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
+	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 1})
+	issue := unittest.AssertExistsAndLoadBean(t, &issue_model.Issue{ID: 1, RepoID: repo.ID})
+	comment := unittest.AssertExistsAndLoadBean(t, &issue_model.Comment{ID: 3, PosterID: doer.ID, IssueID: issue.ID})
+	_ = comment.LoadIssue(db.DefaultContext)
+	issueURL := fmt.Sprintf("/%s/%s/issues/%d", url.PathEscape(repo.OwnerName), url.PathEscape(repo.Name), issue.Index)
+
+	BlockUser(t, doer, blockedUser)
+
+	session := loginUser(t, blockedUser.Name)
+	req := NewRequest(t, "GET", issueURL)
+	resp := session.MakeRequest(t, req, http.StatusOK)
+	htmlDoc := NewHTMLParser(t, resp.Body)
+
+	req = NewRequestWithValues(t, "POST", path.Join(repo.Link(), "/comments/", strconv.FormatInt(comment.ID, 10), "/reactions/react"), map[string]string{
+		"_csrf":   htmlDoc.GetCSRF(),
+		"content": "eyes",
+	})
+	resp = session.MakeRequest(t, req, http.StatusOK)
+	type reactionResponse struct {
+		Empty bool `json:"empty"`
+	}
+
+	var respBody reactionResponse
+	DecodeJSON(t, resp, &respBody)
+
+	assert.EqualValues(t, true, respBody.Empty)
+}
+
+// TestBlockFollow ensures that the doer and blocked user cannot follow each other.
+func TestBlockFollow(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+	doer := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 5})
+	blockedUser := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
+
+	BlockUser(t, doer, blockedUser)
+
+	// Doer cannot follow blocked user.
+	session := loginUser(t, doer.Name)
+	req := NewRequestWithValues(t, "POST", "/"+blockedUser.Name, map[string]string{
+		"_csrf":  GetCSRF(t, session, "/"+blockedUser.Name),
+		"action": "follow",
+	})
+	session.MakeRequest(t, req, http.StatusSeeOther)
+
+	unittest.AssertNotExistsBean(t, &user_model.Follow{UserID: doer.ID, FollowID: blockedUser.ID})
+
+	// Blocked user cannot follow doer.
+	session = loginUser(t, blockedUser.Name)
+	req = NewRequestWithValues(t, "POST", "/"+doer.Name, map[string]string{
+		"_csrf":  GetCSRF(t, session, "/"+doer.Name),
+		"action": "follow",
+	})
+	session.MakeRequest(t, req, http.StatusSeeOther)
+
+	unittest.AssertNotExistsBean(t, &user_model.Follow{UserID: blockedUser.ID, FollowID: doer.ID})
+}
+
+// TestBlockUserFromOrganization ensures that an organisation can block and unblock an user.
+func TestBlockUserFromOrganization(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	doer := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 15})
+	blockedUser := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
+	org := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 17, Type: user_model.UserTypeOrganization})
+	unittest.AssertNotExistsBean(t, &user_model.BlockedUser{BlockID: blockedUser.ID, UserID: org.ID})
+
+	session := loginUser(t, doer.Name)
+	req := NewRequestWithValues(t, "POST", org.OrganisationLink()+"/settings/blocked_users/block", map[string]string{
+		"_csrf": GetCSRF(t, session, org.OrganisationLink()+"/settings/blocked_users"),
+		"uname": blockedUser.Name,
+	})
+	session.MakeRequest(t, req, http.StatusSeeOther)
+	assert.True(t, unittest.BeanExists(t, &user_model.BlockedUser{BlockID: blockedUser.ID, UserID: org.ID}))
+
+	req = NewRequestWithValues(t, "POST", org.OrganisationLink()+"/settings/blocked_users/unblock", map[string]string{
+		"_csrf":   GetCSRF(t, session, org.OrganisationLink()+"/settings/blocked_users"),
+		"user_id": strconv.FormatInt(blockedUser.ID, 10),
+	})
+	session.MakeRequest(t, req, http.StatusSeeOther)
+	unittest.AssertNotExistsBean(t, &user_model.BlockedUser{BlockID: blockedUser.ID, UserID: org.ID})
+}
+
+// TestBlockAddCollaborator ensures that the doer and blocked user cannot add each each other as collaborators.
+func TestBlockAddCollaborator(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	user1 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 10})
+	user2 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+
+	BlockUser(t, user1, user2)
+
+	t.Run("BlockedUser Add Doer", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 2, OwnerID: user2.ID})
+
+		session := loginUser(t, user2.Name)
+		req := NewRequestWithValues(t, "POST", path.Join(repo.Link(), "/settings/collaboration"), map[string]string{
+			"_csrf":        GetCSRF(t, session, path.Join(repo.Link(), "/settings/collaboration")),
+			"collaborator": user1.Name,
+		})
+		session.MakeRequest(t, req, http.StatusSeeOther)
+
+		flashCookie := session.GetCookie(forgejo_context.CookieNameFlash)
+		assert.NotNil(t, flashCookie)
+		assert.EqualValues(t, "error%3DCannot%2Badd%2Bthe%2Bcollaborator%252C%2Bbecause%2Bthey%2Bhave%2Bblocked%2Bthe%2Brepository%2Bowner.", flashCookie.Value)
+	})
+
+	t.Run("Doer Add BlockedUser", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 7, OwnerID: user1.ID})
+
+		session := loginUser(t, user1.Name)
+		req := NewRequestWithValues(t, "POST", path.Join(repo.Link(), "/settings/collaboration"), map[string]string{
+			"_csrf":        GetCSRF(t, session, path.Join(repo.Link(), "/settings/collaboration")),
+			"collaborator": user2.Name,
+		})
+		session.MakeRequest(t, req, http.StatusSeeOther)
+
+		flashCookie := session.GetCookie(forgejo_context.CookieNameFlash)
+		assert.NotNil(t, flashCookie)
+		assert.EqualValues(t, "error%3DCannot%2Badd%2Bthe%2Bcollaborator%252C%2Bbecause%2Bthe%2Brepository%2Bowner%2Bhas%2Bblocked%2Bthem.", flashCookie.Value)
+	})
+}

web_src/css/org.css

@@ -168,6 +168,25 @@
   border-bottom: 1px solid var(--color-secondary);
 }
 
+.organization.teams .repositories .item,
+.organization.teams .members .item,
+.organization.settings .blocked-users .item {
+  padding: 10px 19px;
+}
+
+.organization.teams .repositories .item:not(:last-child),
+.organization.teams .members .item:not(:last-child),
+.organization.settings .blocked-users .item:not(:last-child) {
+  border-bottom: 1px solid var(--color-secondary);
+}
+
+.organization.teams .repositories .item .button,
+.organization.teams .members .item .button,
+.organization.settings .blocked-users .item button {
+  padding: 9px 10px;
+  margin: 0;
+}
+
 .org-team-navbar .active.item {
   background: var(--color-box-body) !important;
 }

web_src/css/user.css

@@ -36,6 +36,19 @@
   width: 100%;
 }
 
+.user.profile .ui.card .extra.content > ul > li .svg {
+  margin-left: 1px;
+  margin-right: 5px;
+}
+
+.user.profile .ui.card .extra.content > ul > li.follow .ui.button,
+.user.profile .ui.card .extra.content > ul > li.block .ui.button {
+  align-items: center;
+  display: flex;
+  justify-content: center;
+  width: 100%;
+}
+
 .user.profile .ui.card #profile-avatar {
   padding: 1rem 1rem 0.25rem;
   justify-content: center;