Pull Requests: add button to compare force pushed commits (#22857)

To quickly see what changed without having to re-read the whole diff.

options/locale/locale_en-US.ini

@@ -1470,6 +1470,7 @@ issues.error_removing_due_date = "Failed to remove the due date."
 issues.push_commit_1 = "added %d commit %s"
 issues.push_commits_n = "added %d commits %s"
 issues.force_push_codes = `force-pushed %[1]s from <a class="ui sha" href="%[3]s"><code>%[2]s</code></a> to <a class="ui sha" href="%[5]s"><code>%[4]s</code></a> %[6]s`
+issues.force_push_compare = Compare
 issues.due_date_form = "yyyy-mm-dd"
 issues.due_date_form_add = "Add due date"
 issues.due_date_form_edit = "Edit"

templates/repo/issue/view_content/comments.tmpl

@@ -707,6 +707,11 @@
 						{{$.locale.TrN (len .Commits) "repo.issues.push_commit_1" "repo.issues.push_commits_n" (len .Commits) $createdStr | Safe}}
 					{{end}}
 				</span>
+				{{if and .IsForcePush $.Issue.PullRequest.BaseRepo.Name}}
+				<span class="ui float right comparebox">
+					<a href="{{$.Issue.PullRequest.BaseRepo.Link}}/compare/{{PathEscape .OldCommit}}..{{PathEscape .NewCommit}}" rel="nofollow" class="ui compare label">{{$.locale.Tr "repo.issues.force_push_compare"}}</a>
+				</span>
+				{{end}}
 			</div>
 			{{if not .IsForcePush}}
 				{{template "repo/commits_list_small" dict "comment" . "root" $}}

web_src/less/_repository.less

@@ -952,6 +952,17 @@
           margin-top: 4px;
         }
 
+        .comparebox {
+          line-height: 32px;
+          vertical-align: middle;
+
+          .compare.label {
+            font-size: 1rem;
+            margin: 0;
+            border: 1px solid var(--color-light-border);
+          }
+        }
+
         .comment-form-reply .footer {
           padding-bottom: 1em;
         }