[GITEA] services: Gracefully handle missing branches

services: in loadOneBranch, return if CountDivergingCommits fail

If we can't count the number of diverging commits for one reason or
another (such as the branch being in the database, but missing from
disk), rather than logging an error and continuing into a crash (because
`divergence` will be nil), return an error instead.

Signed-off-by: Gergely Nagy <forgejo@gergo.csillger.hu>
(cherry picked from commit 8266105f24)

services: Gracefully handle missing branches

When loading branches, if loading one fails, log an error, and ignore
the branch, rather than returning and causing an internal server error.

Ideally, we would only ignore the error if it was caused by a missing
branch, and do it silently, like the respective API endpoint does.
However, veryfing that at this place is not very practical, so for the
time being, ignore any and all branch loading errors.

Signed-off-by: Gergely Nagy <forgejo@gergo.csillger.hu>
(cherry picked from commit e552a8fd62)

tests: Add a testcase for missing branches

This tests the scenario reported in Codeberg/Community#1408: a branch
that is recorded in the database, but missing on disk was causing
internal server errors. With recent changes, that is no longer the case,
the error is logged and then ignored.

This test case tests this behaviour, that the repo's branches page on
the web UI functions even if the git branch is missing.

Signed-off-by: Gergely Nagy <forgejo@gergo.csillger.hu>
(cherry picked from commit e20eb7b385)

tests: More testing in TestDatabaseMissingABranch

In the `TestDatabaseMissingABranch` testcase, make sure that the
branches are in sync between the db and git before deleting a branch via
git, then compare the branch count from the web UI, making sure that it
returns an out-of-sync value first, and the correct one after another
sync.

This is currently tested by scraping the UI, and relies on the fact that
the branch counter is out of date before syncing. If that issue gets
resolved, we'll have to adjust the test to verify the sync another way.

Signed-off-by: Gergely Nagy <forgejo@gergo.csillger.hu>
(cherry picked from commit 8c2ccfcece)
(cherry picked from commit 439fadf563)
(cherry picked from commit 44dd80552c)
(cherry picked from commit 37b91fe6f2)

services/repository/branch.go

@@ -97,7 +97,13 @@ func LoadBranches(ctx context.Context, repo *repo_model.Repository, gitRepo *git
 	for i := range dbBranches {
 		branch, err := loadOneBranch(ctx, repo, dbBranches[i], &rules, repoIDToRepo, repoIDToGitRepo)
 		if err != nil {
-			return nil, nil, 0, fmt.Errorf("loadOneBranch: %v", err)
+			log.Error("loadOneBranch() on repo #%d, branch '%s' failed: %v", repo.ID, dbBranches[i].Name, err)
+
+			// TODO: Ideally, we would only do this if the branch doesn't exist
+			// anymore. That is not practical to check here currently, so we do
+			// this for all kinds of errors.
+			totalNumOfBranches--
+			continue
 		}
 
 		branches = append(branches, branch)
@@ -133,7 +139,7 @@ func loadOneBranch(ctx context.Context, repo *repo_model.Repository, dbBranch *g
 		var err error
 		divergence, err = files_service.CountDivergingCommits(ctx, repo, git.BranchPrefix+branchName)
 		if err != nil {
-			log.Error("CountDivergingCommits: %v", err)
+			return nil, fmt.Errorf("CountDivergingCommits: %v", err)
 		}
 	}
 

tests/integration/repo_branch_test.go

@@ -1,4 +1,5 @@
 // Copyright 2017 The Gitea Authors. All rights reserved.
+// Copyright 2024 The Forgejo Authors c/o Codeberg e.V.. All rights reserved.
 // SPDX-License-Identifier: MIT
 
 package integration
@@ -7,14 +8,21 @@ import (
 	"net/http"
 	"net/url"
 	"path"
+	"strconv"
 	"strings"
 	"testing"
 
+	"code.gitea.io/gitea/models/db"
 	git_model "code.gitea.io/gitea/models/git"
+	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/graceful"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/test"
 	"code.gitea.io/gitea/modules/translation"
+	repo_service "code.gitea.io/gitea/services/repository"
 	"code.gitea.io/gitea/tests"
 
 	"github.com/stretchr/testify/assert"
@@ -159,3 +167,49 @@ func TestCreateBranchInvalidCSRF(t *testing.T) {
 		strings.TrimSpace(htmlDoc.doc.Find(".ui.message").Text()),
 	)
 }
+
+func TestDatabaseMissingABranch(t *testing.T) {
+	onGiteaRun(t, func(t *testing.T, URL *url.URL) {
+		adminUser := unittest.AssertExistsAndLoadBean(t, &user_model.User{IsAdmin: true})
+		session := loginUser(t, "user2")
+
+		// Create two branches
+		testCreateBranch(t, session, "user2", "repo1", "branch/master", "will-be-present", http.StatusSeeOther)
+		testCreateBranch(t, session, "user2", "repo1", "branch/master", "will-be-missing", http.StatusSeeOther)
+
+		// Run the repo branch sync, to ensure the db and git agree.
+		err2 := repo_service.AddAllRepoBranchesToSyncQueue(graceful.GetManager().ShutdownContext(), adminUser.ID)
+		assert.NoError(t, err2)
+
+		// Delete one branch from git only, leaving it in the database
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 1})
+		cmd := git.NewCommand(db.DefaultContext, "branch", "-D").AddDynamicArguments("will-be-missing")
+		_, _, err := cmd.RunStdString(&git.RunOpts{Dir: repo.RepoPath()})
+		assert.NoError(t, err)
+
+		// Verify that loading the repo's branches page works still, and that it
+		// reports at least three branches (master, will-be-present, and
+		// will-be-missing).
+		req := NewRequest(t, "GET", "/user2/repo1/branches")
+		resp := session.MakeRequest(t, req, http.StatusOK)
+		doc := NewHTMLParser(t, resp.Body)
+		firstBranchCount, _ := strconv.Atoi(doc.Find(".repository-menu a[href*='/branches'] b").Text())
+		assert.GreaterOrEqual(t, firstBranchCount, 3)
+
+		// Run the repo branch sync again
+		err2 = repo_service.AddAllRepoBranchesToSyncQueue(graceful.GetManager().ShutdownContext(), adminUser.ID)
+		assert.NoError(t, err2)
+
+		// Verify that loading the repo's branches page works still, and that it
+		// reports one branch less than the first time.
+		//
+		// NOTE: This assumes that the branch counter on the web UI is out of
+		// date before the sync. If that problem gets resolved, we'll have to
+		// find another way to test that the syncing works.
+		req = NewRequest(t, "GET", "/user2/repo1/branches")
+		resp = session.MakeRequest(t, req, http.StatusOK)
+		doc = NewHTMLParser(t, resp.Body)
+		secondBranchCount, _ := strconv.Atoi(doc.Find(".repository-menu a[href*='/branches'] b").Text())
+		assert.Equal(t, firstBranchCount-1, secondBranchCount)
+	})
+}