feat(vcs): blame each merge side pane on the branch it belongs to (#391)

The merge view blamed both side panes against HEAD, so lines that only exist on the merged branch showed as Not Committed Yet. vcs_blame takes an optional revision (validated, passed to git blame --contents -); the merge view blames Yours on HEAD and Theirs on MERGE_HEAD (swapped during a rebase).

Co-authored-by: a-rookie-of-C-language <[email protected]>

crates/ide-host/src/ops/vcs/commands.rs

@@ -201,12 +201,20 @@ pub async fn vcs_file_at(host: &Host, window: &str, path: PathBuf, rev: Option<S
     .await
 }
 
-pub async fn vcs_blame(host: &Host, window: &str, path: PathBuf, text: Option<String>) -> IdeResult<Vec<BlameLine>> {
+pub async fn vcs_blame(
+    host: &Host,
+    window: &str,
+    path: PathBuf,
+    text: Option<String>,
+    revision: Option<String>,
+) -> IdeResult<Vec<BlameLine>> {
     let project = host.project(window)?;
     // An explicit text wins (merge view annotates its side panes, not the worktree).
     let text = text.or_else(|| project.documents.text_of(&path));
     blocking(move || {
-        project.with_repo_of(&path, |r| r.blame(&path, text.as_deref(), project.vcs_encoding(&path, None)?))
+        project.with_repo_of(&path, |r| {
+            r.blame(&path, text.as_deref(), revision.as_deref(), project.vcs_encoding(&path, revision.as_deref())?)
+        })
     })
     .await
 }
@@ -837,7 +845,9 @@ pub(crate) fn register(d: &mut Dispatcher) {
     d.add("vcs_branch_info", |c| async move { vcs_branch_info(&c.host, &c.window, c.arg("repo")?).await });
     d.add("vcs_line_hunks", |c| async move { vcs_line_hunks(&c.host, &c.window, c.arg("path")?) });
     d.add("vcs_file_at", |c| async move { vcs_file_at(&c.host, &c.window, c.arg("path")?, c.arg("rev")?).await });
-    d.add("vcs_blame", |c| async move { vcs_blame(&c.host, &c.window, c.arg("path")?, c.arg("text")?).await });
+    d.add("vcs_blame", |c| async move {
+        vcs_blame(&c.host, &c.window, c.arg("path")?, c.arg("text")?, c.arg("revision")?).await
+    });
     d.add("vcs_log", |c| async move { vcs_log(&c.host, &c.window, c.arg("repo")?, c.arg("query")?).await });
     d.add("vcs_commit_files", |c| async move {
         vcs_commit_files(&c.host, &c.window, c.arg("repo")?, c.arg("commit")?).await

crates/ide-host/tests/vcs_encoding.rs

@@ -96,7 +96,7 @@ async fn gbk_document_gutter_diff_stage_and_rollback_share_encoding() {
     project.documents.save(doc.id).unwrap();
     assert_eq!(std::fs::read(&path).unwrap(), original);
     assert!(vcs::vcs_line_hunks(&host, "main", path.clone()).unwrap().is_empty());
-    assert!(vcs::vcs_blame(&host, "main", path.clone(), None).await.unwrap().iter().all(|l| l.author == "Test"));
+    assert!(vcs::vcs_blame(&host, "main", path.clone(), None, None).await.unwrap().iter().all(|l| l.author == "Test"));
     // Missing working files still use configured encoding for historical content.
     project.documents.close(doc.id);
     let mut defaults = project.documents.file_defaults();

crates/ide-vcs/src/lib.rs

@@ -591,13 +591,16 @@ impl Repo {
     }
     /// One entry per line of the current text (`current_text`, or the file on disk).
     /// Lines not yet committed carry an all-zero commit id and author "Not Committed Yet".
+    /// `revision` is the history to blame against (default `HEAD`); the merge view
+    /// blames each side pane on the branch it belongs to (e.g. `MERGE_HEAD`).
     pub fn blame(
         &self,
         path: &Path,
         current_text: Option<&str>,
+        revision: Option<&str>,
         encoding: &'static Encoding,
     ) -> IdeResult<Vec<BlameLine>> {
-        write::blame(self, path, current_text, encoding)
+        write::blame(self, path, current_text, revision, encoding)
     }
     /// Commits newest-first in topological order (children before parents).
     ///

crates/ide-vcs/src/write.rs

@@ -47,9 +47,14 @@ pub(crate) fn blame(
     r: &Repo,
     path: &Path,
     current_text: Option<&str>,
+    revision: Option<&str>,
     encoding: &'static Encoding,
 ) -> IdeResult<Vec<BlameLine>> {
     let rel = r.rel_path(path)?;
+    let revision = match revision {
+        Some(rev) => check_rev(rev)?,
+        None => "HEAD",
+    };
     let disk = match std::fs::read(r.abs_path(&rel)) {
         Ok(bytes) => bytes,
         Err(_) if current_text.is_some() => Vec::new(),
@@ -74,14 +79,14 @@ pub(crate) fn blame(
     let line_count = text.split_inclusive('\n').count();
     let tracked_in_head = {
         let repo = r.gix()?;
-        crate::repo::blob_at(&repo, &rel, "HEAD")?.is_some()
+        crate::repo::blob_at(&repo, &rel, revision)?.is_some()
     };
     if !tracked_in_head {
         return Ok(uncommitted_lines(line_count));
     }
     let out = run(
         r.root(),
-        &["--literal-pathspecs", "blame", "--porcelain", "--contents", "-", "--", &rel],
+        &["--literal-pathspecs", "blame", "--porcelain", "--contents", "-", revision, "--", &rel],
         Some(&contents),
     )?;
     let mut lines = crate::blame::parse_porcelain(&out.stdout_str());

crates/ide-vcs/tests/git_workflows.rs

@@ -777,7 +777,7 @@ fn add_to_vcs_annotate_and_history() {
     repo.stage(&[fx.path("new/b.txt")]).unwrap();
     assert_eq!(status_of(&repo.status().unwrap(), "new/b.txt").unwrap().staged, Some(ChangeKind::Added));
 
-    let blame = repo.blame(&fx.path("a.txt"), Some("1\nchanged\nunsaved\n"), encoding_rs::UTF_8).unwrap();
+    let blame = repo.blame(&fx.path("a.txt"), Some("1\nchanged\nunsaved\n"), None, encoding_rs::UTF_8).unwrap();
     assert_eq!(blame.len(), 3);
     assert_eq!(blame[0].commit, first);
     assert_eq!(blame[1].commit, second);

crates/ide-vcs/tests/repo.rs

@@ -441,7 +441,7 @@ fn blame_with_unsaved_edits() {
     let second = fx.commit_all("second");
     let repo = fx.repo();
 
-    let lines = repo.blame(&fx.path("b.txt"), None, encoding_rs::UTF_8).unwrap();
+    let lines = repo.blame(&fx.path("b.txt"), None, None, encoding_rs::UTF_8).unwrap();
     assert_eq!(lines.len(), 3);
     assert_eq!(lines[0].commit, first);
     assert_eq!(lines[1].commit, second);
@@ -449,7 +449,7 @@ fn blame_with_unsaved_edits() {
     assert_eq!(lines[0].author, "Test User");
     assert!(lines[0].time_ms > 1.0e12);
 
-    let lines = repo.blame(&fx.path("b.txt"), Some("one\nedited\nthree\nfour"), encoding_rs::UTF_8).unwrap();
+    let lines = repo.blame(&fx.path("b.txt"), Some("one\nedited\nthree\nfour"), None, encoding_rs::UTF_8).unwrap();
     assert_eq!(lines.len(), 4);
     assert_eq!(lines[0].commit, first);
     assert!(lines[1].commit.bytes().all(|b| b == b'0'));
@@ -457,11 +457,40 @@ fn blame_with_unsaved_edits() {
     assert_eq!(lines[2].commit, first);
     assert_eq!(lines[3].author, "Not Committed Yet");
 
-    let lines = repo.blame(&fx.path("untracked.txt"), Some("x\ny\n"), encoding_rs::UTF_8).unwrap();
+    let lines = repo.blame(&fx.path("untracked.txt"), Some("x\ny\n"), None, encoding_rs::UTF_8).unwrap();
     assert_eq!(lines.len(), 2);
     assert!(lines.iter().all(|l| l.author == "Not Committed Yet"));
 }
 
+#[test]
+fn blame_against_another_revision() {
+    // The merge view blames each side pane on the branch it belongs to: lines that
+    // only exist on the merged branch show their real history, not "Not Committed Yet".
+    let fx = Fixture::new();
+    fx.write("b.txt", "one\nthree\n");
+    let first = fx.commit_all("first");
+    fx.write("b.txt", "one\nTWO\nthree\n");
+    fx.commit_all("second");
+    fx.git(&["checkout", "-q", "-b", "feature", &first]);
+    fx.write("b.txt", "one\nfeature\nthree\n");
+    let feature = fx.commit_all("feature line");
+    fx.git(&["checkout", "-q", "main"]);
+    let repo = fx.repo();
+
+    // Blaming the feature content against HEAD marks its extra line uncommitted…
+    let text = "one\nfeature\nthree\n";
+    let lines = repo.blame(&fx.path("b.txt"), Some(text), Some("HEAD"), encoding_rs::UTF_8).unwrap();
+    assert_eq!(lines.len(), 3);
+    assert_eq!(lines[0].commit, first);
+    assert_eq!(lines[1].author, "Not Committed Yet");
+    assert_eq!(lines[2].commit, first);
+    // …while blaming it against the feature commit resolves its real history.
+    let lines = repo.blame(&fx.path("b.txt"), Some(text), Some(&feature), encoding_rs::UTF_8).unwrap();
+    assert_eq!(lines[1].commit, feature);
+    assert_eq!(lines[1].summary, "feature line");
+    assert!(repo.blame(&fx.path("b.txt"), Some(text), Some("no-such-ref"), encoding_rs::UTF_8).is_err());
+}
+
 #[test]
 fn log_filters_pagination_and_refs() {
     let fx = Fixture::new();
@@ -1379,7 +1408,7 @@ fn encoded_java_hunks_staging_blame_and_partial_commit_preserve_bytes() {
             let repo = fx.repo();
             assert_eq!(repo.file_at(&path, None, encoding).unwrap().as_deref(), Some(old.as_str()));
             assert!(
-                repo.blame(&path, Some(&old.replace("\r\n", "\n")), encoding)
+                repo.blame(&path, Some(&old.replace("\r\n", "\n")), None, encoding)
                     .unwrap()
                     .iter()
                     .all(|line| line.author == "Test User")

src-tauri/src/commands/vcs.rs

@@ -57,8 +57,9 @@ pub async fn vcs_blame(
     state: State<'_, AppState>,
     path: PathBuf,
     text: Option<String>,
+    revision: Option<String>,
 ) -> IdeResult<Vec<BlameLine>> {
-    ide_host::ops::vcs::vcs_blame(&state.host, window.label(), path, text).await
+    ide_host::ops::vcs::vcs_blame(&state.host, window.label(), path, text, revision).await
 }
 
 #[tauri::command]

src/bindings.ts

@@ -413,7 +413,7 @@ export const commands = {
 	/**  Gutter change markers for a file, computed against its current (unsaved) text. */
 	vcsLineHunks: (path: string) => typedError<LineHunk[], IdeError>(__TAURI_INVOKE("vcs_line_hunks", { path })),
 	vcsFileAt: (path: string, rev: string | null) => typedError<string | null, IdeError>(__TAURI_INVOKE("vcs_file_at", { path, rev })),
-	vcsBlame: (path: string, text: string | null) => typedError<BlameLine[], IdeError>(__TAURI_INVOKE("vcs_blame", { path, text })),
+	vcsBlame: (path: string, text: string | null, revision: string | null) => typedError<BlameLine[], IdeError>(__TAURI_INVOKE("vcs_blame", { path, text, revision })),
 	vcsLog: (repo: string | null, query: LogQuery) => typedError<Commit[], IdeError>(__TAURI_INVOKE("vcs_log", { repo, query })),
 	vcsCommitFiles: (repo: string | null, commit: string) => typedError<ChangedFile[], IdeError>(__TAURI_INVOKE("vcs_commit_files", { repo, commit })),
 	/**  Combined changes of several commits, `commits` oldest first. */

src/editor/lsp/authorLens.ts

@@ -76,7 +76,7 @@ export function blameFor(path: string, text: Text): Promise<BlameLine[] | null>
   const hit = cache.get(path);
   if (hit && (hit.text === text || hit.text === null)) return hit.lines;
   const entry: Entry = { text, lines: Promise.resolve(null) };
-  entry.lines = call(commands.vcsBlame(path, null)).then(
+  entry.lines = call(commands.vcsBlame(path, null, null)).then(
     (lines) => lines,
     () => {
       entry.text = null;

src/features/vcs/MergeEditor.tsx

@@ -315,6 +315,9 @@ export function MergeEditor({ input }: { input: EditorInput }) {
 
   // IDEA's merge view: F7 / Shift+F7 jump between conflicts; each side pane can
   // annotate its version with Git Blame from the context menu.
+  // Each side pane blames on the branch it belongs to, so lines that only exist on
+  // the other branch show their real history instead of "Not Committed Yet".
+  const otherRev = state?.sides.commit ?? "HEAD";
   const onKeyDown = (e: React.KeyboardEvent) => {
     if (e.key === "F7") {
       e.preventDefault();
@@ -322,7 +325,7 @@ export function MergeEditor({ input }: { input: EditorInput }) {
     }
   };
 
-  const sideMenu = (e: React.MouseEvent, viewRef: { current: EditorView | null }, text: string) => {
+  const sideMenu = (e: React.MouseEvent, viewRef: { current: EditorView | null }, text: string, revision?: string) => {
     const view = viewRef.current;
     if (!view) return;
     e.preventDefault();
@@ -330,7 +333,7 @@ export function MergeEditor({ input }: { input: EditorInput }) {
       {
         label: "Annotate with Git Blame",
         icon: "changelist",
-        run: () => void toggleAnnotations(view, path, text),
+        run: () => void toggleAnnotations(view, path, text, revision),
       },
     ]);
   };
@@ -392,7 +395,7 @@ export function MergeEditor({ input }: { input: EditorInput }) {
           className={styles.pane}
           aria-label={tx("Your version")}
           role="region"
-          onContextMenu={(e) => sideMenu(e, oursView, state?.ours ?? "")}
+          onContextMenu={(e) => sideMenu(e, oursView, state?.ours ?? "", state?.sides.reversed ? otherRev : "HEAD")}
         />
         <div ref={resultRef} className={styles.pane} aria-label={tx("Result")} role="region" />
         <div
@@ -400,7 +403,7 @@ export function MergeEditor({ input }: { input: EditorInput }) {
           className={styles.pane}
           aria-label={tx("Their version")}
           role="region"
-          onContextMenu={(e) => sideMenu(e, theirsView, state?.theirs ?? "")}
+          onContextMenu={(e) => sideMenu(e, theirsView, state?.theirs ?? "", state?.sides.reversed ? "HEAD" : otherRev)}
         />
       </div>
     </div>

src/features/vcs/blame.ts

@@ -106,7 +106,7 @@ class BlameRefresher implements PluginValue {
   private schedule(delay: number) {
     clearTimeout(this.timer);
     this.timer = setTimeout(() => {
-      void call(commands.vcsBlame(this.path, null))
+      void call(commands.vcsBlame(this.path, null, null))
         .then((lines) => {
           if (!this.destroyed && this.view.state.field(blameField, false))
             this.view.dispatch({ effects: setBlame.of(lines) });
@@ -207,14 +207,15 @@ function setAnnotations(view: EditorView, lines: BlameLine[] | null, path: strin
   view.dispatch({ effects: blameCompartment.reconfigure(lines ? blameExtension(lines, path, live) : []) });
 }
 
-/** Toggles annotations in `view`; `text` blames that content instead of the file on disk. */
-export async function toggleAnnotations(view: EditorView, path: string, text?: string) {
+/** Toggles annotations in `view`; `text` blames that content instead of the file on
+ * disk, `revision` the history it is blamed on (default HEAD). */
+export async function toggleAnnotations(view: EditorView, path: string, text?: string, revision?: string) {
   if (annotationsShown(view)) {
     setAnnotations(view, null, path, false);
     return;
   }
   try {
-    const lines = await call(commands.vcsBlame(path, text ?? null));
+    const lines = await call(commands.vcsBlame(path, text ?? null, revision ?? null));
     setAnnotations(view, lines, path, text === undefined);
   } catch (e) {
     notifications().notify({