Expand code diffs against the commits repo

When expanding code diffs, the expansion should search for more context
in the commits repo, rather than in the repo in context, because the
commit may not be available in the base repo. For example, when
previewing a pull request, the commit is not in the target repo yet -
it's in the fork.

Fixes #3746.

Signed-off-by: Gergely Nagy <forgejo@gergo.csillger.hu>

templates/repo/diff/section_split.tmpl

@@ -18,17 +18,17 @@
 					<td class="lines-num lines-num-old">
 						<div class="tw-flex">
 						{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 5)}}
-							<button class="code-expander-button" hx-target="closest tr" hx-get="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}?{{$line.GetBlobExcerptQuery}}&style=split&direction=down&wiki={{$.root.PageIsWiki}}&anchor=diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
+							<button class="code-expander-button" hx-target="closest tr" hx-get="{{$.root.CommitRepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}?{{$line.GetBlobExcerptQuery}}&style=split&direction=down&wiki={{$.root.PageIsWiki}}&anchor=diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
 								{{svg "octicon-fold-down"}}
 							</button>
 						{{end}}
 						{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 4)}}
-							<button class="code-expander-button" hx-target="closest tr" hx-get="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}?{{$line.GetBlobExcerptQuery}}&style=split&direction=up&wiki={{$.root.PageIsWiki}}&anchor=diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
+							<button class="code-expander-button" hx-target="closest tr" hx-get="{{$.root.CommitRepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}?{{$line.GetBlobExcerptQuery}}&style=split&direction=up&wiki={{$.root.PageIsWiki}}&anchor=diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
 								{{svg "octicon-fold-up"}}
 							</button>
 						{{end}}
 						{{if eq $line.GetExpandDirection 2}}
-							<button class="code-expander-button" hx-target="closest tr" hx-get="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}?{{$line.GetBlobExcerptQuery}}&style=split&direction=&wiki={{$.root.PageIsWiki}}&anchor=diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
+							<button class="code-expander-button" hx-target="closest tr" hx-get="{{$.root.CommitRepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}?{{$line.GetBlobExcerptQuery}}&style=split&direction=&wiki={{$.root.PageIsWiki}}&anchor=diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
 								{{svg "octicon-fold"}}
 							</button>
 						{{end}}

templates/repo/diff/section_unified.tmpl

@@ -14,17 +14,17 @@
 					<td colspan="2" class="lines-num">
 						<div class="tw-flex">
 							{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 5)}}
-								<button class="code-expander-button" hx-target="closest tr" hx-get="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}?{{$line.GetBlobExcerptQuery}}&style=unified&direction=down&wiki={{$.root.PageIsWiki}}&anchor=diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
+								<button class="code-expander-button" hx-target="closest tr" hx-get="{{$.root.CommitRepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}?{{$line.GetBlobExcerptQuery}}&style=unified&direction=down&wiki={{$.root.PageIsWiki}}&anchor=diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
 									{{svg "octicon-fold-down"}}
 								</button>
 							{{end}}
 							{{if or (eq $line.GetExpandDirection 3) (eq $line.GetExpandDirection 4)}}
-								<button class="code-expander-button" hx-target="closest tr" hx-get="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}?{{$line.GetBlobExcerptQuery}}&style=unified&direction=up&wiki={{$.root.PageIsWiki}}&anchor=diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
+								<button class="code-expander-button" hx-target="closest tr" hx-get="{{$.root.CommitRepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}?{{$line.GetBlobExcerptQuery}}&style=unified&direction=up&wiki={{$.root.PageIsWiki}}&anchor=diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
 									{{svg "octicon-fold-up"}}
 								</button>
 							{{end}}
 							{{if eq $line.GetExpandDirection 2}}
-								<button class="code-expander-button" hx-target="closest tr" hx-get="{{$.root.RepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}?{{$line.GetBlobExcerptQuery}}&style=unified&direction=&wiki={{$.root.PageIsWiki}}&anchor=diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
+								<button class="code-expander-button" hx-target="closest tr" hx-get="{{$.root.CommitRepoLink}}/blob_excerpt/{{PathEscape $.root.AfterCommitID}}?{{$line.GetBlobExcerptQuery}}&style=unified&direction=&wiki={{$.root.PageIsWiki}}&anchor=diff-{{$file.NameHash}}K{{$line.SectionInfo.RightIdx}}">
 									{{svg "octicon-fold"}}
 								</button>
 							{{end}}

tests/integration/compare_test.go

@@ -15,8 +15,11 @@ import (
 	repo_model "code.gitea.io/gitea/models/repo"
 	unit_model "code.gitea.io/gitea/models/unit"
 	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/gitrepo"
+	"code.gitea.io/gitea/modules/optional"
 	repo_service "code.gitea.io/gitea/services/repository"
+	files_service "code.gitea.io/gitea/services/repository/files"
 	"code.gitea.io/gitea/tests"
 
 	"github.com/stretchr/testify/assert"
@@ -213,3 +216,43 @@ func TestCompareCrossRepo(t *testing.T) {
 		})
 	})
 }
+
+func TestCompareCodeExpand(t *testing.T) {
+	onGiteaRun(t, func(t *testing.T, u *url.URL) {
+		owner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
+
+		// Create a new repository, with a file that has many lines
+		repo, _, f := CreateDeclarativeRepoWithOptions(t, owner, DeclarativeRepoOptions{
+			Files: optional.Some([]*files_service.ChangeRepoFile{
+				{
+					Operation:     "create",
+					TreePath:      "docs.md",
+					ContentReader: strings.NewReader("01\n02\n03\n04\n05\n06\n07\n08\n09\n0a\n0b\n0c\n0d\n0e\n0f\n10\n11\n12\n12\n13\n14\n15\n16\n17\n18\n19\n1a\n1b\n1c\n1d\n1e\n1f\n20\n"),
+				},
+			}),
+		})
+		defer f()
+
+		// Fork the repository
+		forker := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+		session := loginUser(t, forker.Name)
+		testRepoFork(t, session, owner.Name, repo.Name, forker.Name, repo.Name+"-copy")
+		testCreateBranch(t, session, forker.Name, repo.Name+"-copy", "branch/main", "code-expand", http.StatusSeeOther)
+
+		// Edit the file, insert a line somewhere in the middle
+		testEditFile(t, session, forker.Name, repo.Name+"-copy", "code-expand", "docs.md",
+			"01\n02\n03\n04\n05\n06\n07\n08\n09\n0a\n0b\n0c\n0d\n0e\n0f\n10\n11\nHELLO WORLD!\n12\n12\n13\n14\n15\n16\n17\n18\n19\n1a\n1b\n1c\n1d\n1e\n1f\n20\n",
+		)
+
+		t.Run("code expander targets the fork", func(t *testing.T) {
+			defer tests.PrintCurrentTest(t)()
+
+			req := NewRequestf(t, "GET", "%s/%s/compare/main...%s/%s:code-expand",
+				owner.Name, repo.Name, forker.Name, repo.Name+"-copy")
+			resp := session.MakeRequest(t, req, http.StatusOK)
+			htmlDoc := NewHTMLParser(t, resp.Body)
+			htmlDoc.AssertElement(t, fmt.Sprintf("button.code-expander-button[hx-get^='/%s/%s/blob_excerpt/'] svg.octicon-fold-up", forker.Name, repo.Name+"-copy"), true)
+			htmlDoc.AssertElement(t, fmt.Sprintf("button.code-expander-button[hx-get^='/%s/%s/blob_excerpt/'] svg.octicon-fold-down", forker.Name, repo.Name+"-copy"), true)
+		})
+	})
+}