[UI] Show AGit label on merged PR

- The label wasn't show on merged PRs.
- Integration test added

(cherry picked from commit 358ec8002e)

templates/repo/issue/view_title.tmpl

@@ -63,6 +63,15 @@
 						<a {{if gt .Issue.PullRequest.Merger.ID 0}}href="{{.Issue.PullRequest.Merger.HomeLink}}"{{end}}>{{.Issue.PullRequest.Merger.GetDisplayName}}</a>
 						<span class="pull-desc">{{ctx.Locale.TrN .NumCommits "repo.pulls.merged_title_desc_one" "repo.pulls.merged_title_desc_few" .NumCommits $headHref $baseHref $mergedStr}}</span>
 					{{end}}
+					{{if .MadeUsingAGit}}
+						{{/* TODO: Move documentation link to the instructions at the bottom of the PR, show instructions when clicking label */}}
+						{{/* Note: #agit-label is necessary for testing whether the label appears when it should in tests/integration/git_test.go */}}
+						<a target="_blank" rel="noopener" href="https://forgejo.org/docs/latest/user/agit-support/">
+							<span id="agit-label" data-tooltip-content="{{ctx.Locale.Tr "repo.pulls.agit_explanation"}}" class="ui small label">
+								{{ctx.Locale.Tr "repo.pulls.made_using_agit"}}
+							</span>
+						</a>
+					{{end}}
 				{{else}}
 					{{if .Issue.OriginalAuthor}}
 						<span id="pull-desc" class="pull-desc">{{.Issue.OriginalAuthor}} {{ctx.Locale.TrN .NumCommits "repo.pulls.title_desc_one" "repo.pulls.title_desc_few" .NumCommits $headHref $baseHref}}</span>

tests/integration/git_test.go

@@ -1063,6 +1063,18 @@ func doCreateAgitFlowPull(dstPath string, ctx *APITestContext, baseBranch, headB
 		})
 
 		t.Run("Merge", doAPIMergePullRequest(*ctx, ctx.Username, ctx.Reponame, pr1.Index))
+
+		t.Run("AGitLabelIsPresent Merged", func(t *testing.T) {
+			defer tests.PrintCurrentTest(t)()
+
+			session := loginUser(t, ctx.Username)
+
+			req := NewRequest(t, "GET", fmt.Sprintf("/%s/%s/pulls/%d", url.PathEscape(ctx.Username), url.PathEscape(ctx.Reponame), pr2.Index))
+			resp := session.MakeRequest(t, req, http.StatusOK)
+			htmlDoc := NewHTMLParser(t, resp.Body)
+			htmlDoc.AssertElement(t, "#agit-label", true)
+		})
+
 		t.Run("CheckoutMasterAgain", doGitCheckoutBranch(dstPath, "master"))
 	}
 }