feat(diff): add branch scope to context panel diff view

Show every change on the current branch relative to its base in the Changed/Staged/Last turn dropdown. The base comes from the branch's reflog record or an explicit per-branch user choice (persisted), never a main/master guess; when git has no record the user picks a base once from a searchable branch list. - server: GET /api/git/branch-base (reflog-derived base), GET /api/git/range-files (name-status -z with rename/copy destination paths and -C copy detection) - shared UI: optional getBranchBase/getGitRangeFiles runtime APIs with boundary parsing; persisted per-branch overrides keyed by runtime+directory+branch - DiffView: branch scope with confirmed-unavailability coercion of persisted tabs (detached HEAD, default-branch checkout, metadata settled without a default), range-invalidated diff cache guarded against stale completions, bounded branch-metadata retry, read-only diff actions in branch scope; hidden in VS Code - helper module branchDiffScope.ts with tests for coercion, availability, race conditions, and retry exhaustion
2026-08-22 01:10:19 +03:00
parent 9f7d839fc6
commit 0b01f5ae2d
24 changed files with 1582 additions and 38 deletions
@@ -428,6 +428,49 @@ export function registerGitRoutes(app) {
    }
  });

+  app.get('/api/git/branch-base', async (req, res) => {
+    const { getBranchBase } = await getGitLibraries();
+    try {
+      const directory = resolveDirectoryQuery(req.query.directory);
+      if (!directory) {
+        return res.status(400).json({ error: 'directory parameter is required' });
+      }
+
+      const branch = resolveDirectoryQuery(req.query.branch);
+      if (!branch) {
+        return res.status(400).json({ error: 'branch parameter is required' });
+      }
+
+      const result = await getBranchBase(directory, branch);
+      res.json(result);
+    } catch (error) {
+      console.error('Failed to get branch base:', error);
+      res.status(500).json({ error: error.message || 'Failed to get branch base' });
+    }
+  });
+
+  app.get('/api/git/range-files', async (req, res) => {
+    const { getRangeFiles } = await getGitLibraries();
+    try {
+      const directory = resolveDirectoryQuery(req.query.directory);
+      if (!directory) {
+        return res.status(400).json({ error: 'directory parameter is required' });
+      }
+
+      const base = resolveDirectoryQuery(req.query.base);
+      const head = resolveDirectoryQuery(req.query.head);
+      if (!base || !head) {
+        return res.status(400).json({ error: 'base and head parameters are required' });
+      }
+
+      const files = await getRangeFiles(directory, { base, head });
+      res.json({ files });
+    } catch (error) {
+      console.error('Failed to get git range files:', error);
+      res.status(500).json({ error: error.message || 'Failed to get git range files' });
+    }
+  });
+
  app.post('/api/git/revert', async (req, res) => {
    const { revertFile } = await getGitLibraries();
    try {
@@ -2654,6 +2654,71 @@ export async function getRangeDiff(directory, { base, head, path: filePath, cont
  return diff;
 }

+const BRANCH_CREATION_SOURCE_RE = /^branch: Created from (.+)$/;
+
+/**
+ * Parse a branch reflog (`git reflog show --format=%gs <branch>`) and return the
+ * ref the branch was created from, when that source is itself a named ref.
+ *
+ * Returns null when the branch was created from `HEAD@{...}` or a raw commit
+ * (detached start): the original branch name is not recorded anywhere in that
+ * case, and guessing a base from commit topology would be a heuristic, not an
+ * answer. Callers should ask the user to pick a base instead.
+ */
+export function parseBranchCreationSource(reflogText) {
+  const lines = String(reflogText || '')
+    .split('\n')
+    .map((line) => line.trim())
+    .filter(Boolean);
+  // Reflog lists newest entries first; the creation entry is the oldest one.
+  for (let index = lines.length - 1; index >= 0; index -= 1) {
+    const match = lines[index].match(BRANCH_CREATION_SOURCE_RE);
+    if (!match) continue;
+    const source = match[1].trim();
+    if (!source || /^HEAD@/.test(source) || /^[0-9a-f]{7,40}$/i.test(source)) {
+      return null;
+    }
+    return source;
+  }
+  return null;
+}
+
+/**
+ * Resolve the branch the given branch was created from, from its reflog.
+ * Returns { base: null } when git has no authoritative record (clone, detached
+ * start, reflog expired) — callers must not fall back to main/master.
+ */
+export async function getBranchBase(directory, branch) {
+  const branchName = String(branch || '').trim();
+  if (!branchName) {
+    throw new Error('branch is required');
+  }
+
+  const { git } = await createRepositoryGitContext(directory);
+
+  let reflog = '';
+  try {
+    reflog = await git.raw(['reflog', 'show', '--format=%gs', branchName]);
+  } catch {
+    return { base: null };
+  }
+
+  const source = parseBranchCreationSource(reflog);
+  if (!source || source === branchName) {
+    return { base: null };
+  }
+
+  const resolves = await git
+    .raw(['rev-parse', '--verify', '--quiet', source])
+    .then((value) => Boolean(String(value || '').trim()))
+    .catch(() => false);
+  if (!resolves) {
+    return { base: null };
+  }
+
+  return { base: source };
+}
+
 export async function getRangeFiles(directory, { base, head } = {}) {
  const { git } = await createRepositoryGitContext(directory);
  const baseRef = typeof base === 'string' ? base.trim() : '';
@@ -2673,11 +2738,26 @@ export async function getRangeFiles(directory, { base, head } = {}) {
    // ignore
  }

-  const raw = await git.raw(['diff', '--name-only', `${resolvedBase}...${headRef}`]);
-  return String(raw || '')
-    .split('\n')
-    .map((l) => l.trim())
-    .filter(Boolean);
+  // `-C` (copy detection among changed files only, so cheap) makes copies
+  // surface as C entries instead of plain additions; rename detection is on
+  // by default.
+  const raw = await git.raw(['diff', '--name-status', '-z', '-C', `${resolvedBase}...${headRef}`]);
+  // -z format: STATUS\0PATH\0[ORIG\0] repeated. For rename/copy entries
+  // (`R100`, `C75`) the first path token is the ORIGINAL path and the second
+  // is the DESTINATION — the diff (and the UI) must address the destination.
+  const tokens = String(raw || '').split('\0');
+  const files = [];
+  for (let index = 0; index < tokens.length; index += 1) {
+    const status = (tokens[index] || '').trim();
+    if (!status) continue;
+    const isRenameOrCopy = status.startsWith('R') || status.startsWith('C');
+    const path = isRenameOrCopy ? (tokens[index + 2] || '').trim() : (tokens[index + 1] || '').trim();
+    index += isRenameOrCopy ? 2 : 1;
+    if (path) {
+      files.push({ path, status: status.charAt(0) });
+    }
+  }
+  return files;
 }

 const IMAGE_EXTENSIONS = ['png', 'jpg', 'jpeg', 'gif', 'svg', 'webp', 'ico', 'bmp', 'avif'];
@@ -28,6 +28,8 @@ import {
  getDiff,
  getFileDiff,
  validateWorktreeCreate,
+  parseBranchCreationSource,
+  getRangeFiles,
 } from './service.js';

 // ---------------------------------------------------------------------------
@@ -1336,3 +1338,94 @@ describe.runIf(canRunGit())('getRangeDiff', () => {
    expect(diff).toContain('feature.txt');
  });
 });
+
+describe('parseBranchCreationSource', () => {
+  it('returns the source ref from the oldest creation entry', () => {
+    // Reflog lists newest entries first; creation is the last line.
+    const reflog = [
+      'commit: abc123',
+      'branch: Created from origin/main',
+    ].join('\n');
+    expect(parseBranchCreationSource(reflog)).toBe('origin/main');
+  });
+
+  it('returns null when the branch was created from a detached HEAD pointer', () => {
+    const reflog = 'branch: Created from HEAD@{0}';
+    expect(parseBranchCreationSource(reflog)).toBeNull();
+  });
+
+  it('returns null when the branch was created from a raw commit', () => {
+    const reflog = 'branch: Created from 9a3b2c1d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b';
+    expect(parseBranchCreationSource(reflog)).toBeNull();
+  });
+
+  it('returns null when there is no creation entry', () => {
+    const reflog = ['commit: abc123', 'reset: moving to HEAD'].join('\n');
+    expect(parseBranchCreationSource(reflog)).toBeNull();
+  });
+
+  it('returns null for empty input', () => {
+    expect(parseBranchCreationSource('')).toBeNull();
+    expect(parseBranchCreationSource(undefined)).toBeNull();
+  });
+});
+
+describe.runIf(canRunGit())('getRangeFiles', () => {
+  it('returns added and modified paths with their status letters', async () => {
+    const { repository } = createRepositoryWithRemote();
+    fs.writeFileSync(path.join(repository, 'added.txt'), 'new\n');
+    fs.writeFileSync(path.join(repository, 'README.md'), '# Test\nchanged\n');
+    runGit(repository, ['add', 'added.txt', 'README.md']);
+    runGit(repository, ['commit', '-m', 'changes']);
+
+    const files = await getRangeFiles(repository, { base: 'react', head: 'next' });
+
+    expect(files).toEqual(expect.arrayContaining([
+      { path: 'added.txt', status: 'A' },
+      { path: 'README.md', status: 'M' },
+    ]));
+  });
+
+  it('reports the destination path for renamed files, including spaces', async () => {
+    const { repository } = createRepositoryWithRemote();
+    // The original file must exist in the base: rename detection pairs a
+    // deletion against an addition relative to base, not within the branch.
+    fs.writeFileSync(path.join(repository, 'old name with spaces.md'), '# Test\n');
+    runGit(repository, ['add', 'old name with spaces.md']);
+    runGit(repository, ['commit', '-m', 'add file to rename']);
+    runGit(repository, ['push', 'origin', 'HEAD:react']);
+    // Spaces in filenames exercise the -z token split: a newline split would
+    // mangle these paths long before status letters matter.
+    fs.renameSync(path.join(repository, 'old name with spaces.md'), path.join(repository, 'new name with spaces.md'));
+    runGit(repository, ['add', '-A']);
+    runGit(repository, ['commit', '-m', 'rename']);
+
+    const files = await getRangeFiles(repository, { base: 'react', head: 'next' });
+
+    const renameEntry = files.find((file) => file.status === 'R');
+    expect(renameEntry).toBeDefined();
+    expect(renameEntry.path).toBe('new name with spaces.md');
+    expect(files.some((file) => file.path === 'old name with spaces.md')).toBe(false);
+  });
+
+  it('reports the destination path for copied files', async () => {
+    const { repository } = createRepositoryWithRemote();
+    // The source must exist in the base. Copy detection needs the repository's
+    // own `diff.renames=copies` setting on top of the service's -C flag; the
+    // parser must survive whatever C entries git emits.
+    runGit(repository, ['config', 'diff.renames', 'copies']);
+    fs.writeFileSync(path.join(repository, 'copied source.md'), '# Copy me\n');
+    runGit(repository, ['add', 'copied source.md']);
+    runGit(repository, ['commit', '-m', 'add source']);
+    runGit(repository, ['push', 'origin', 'HEAD:react']);
+    fs.copyFileSync(path.join(repository, 'copied source.md'), path.join(repository, 'copied destination.md'));
+    runGit(repository, ['add', '-A']);
+    runGit(repository, ['commit', '-m', 'copy']);
+
+    const files = await getRangeFiles(repository, { base: 'react', head: 'next' });
+
+    const copyEntry = files.find((file) => file.status === 'C');
+    expect(copyEntry).toBeDefined();
+    expect(copyEntry.path).toBe('copied destination.md');
+  });
+});