From 436e53e61495ddcd15b8a5cab4c4edd63af37753 Mon Sep 17 00:00:00 2001
From: poketopa <lhs5427ll@gmail.com>
Date: Mon, 19 Oct 2026 18:09:31 +0900
Subject: [PATCH 1/2] test(diff): cover renamesFromRewrites in findSimilar

Add two cases for Diff#findSimilar:

- With renamesFromRewrites, the old side of a rewritten file is a
  rename source, so moving its content to a new path is reported as
  Added + Renamed.
- renamesFromRewrites: false must not clear renames.

Both fail on main, where renamesFromRewrites is passed to renames().
---
 tests/diff.spec.ts | 47 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/tests/diff.spec.ts b/tests/diff.spec.ts
index 0ee56fca..80b101f8 100644
--- a/tests/diff.spec.ts
+++ b/tests/diff.spec.ts
@@ -231,4 +231,51 @@ B
     expect(deltas.length).toBe(expected.length);
     expect(deltas.map(flattenDiffDelta)).toEqual(expect.arrayContaining(expected));
   });
+
+  it('find renamed diff delta from rewritten file', async () => {
+    const p = await useFixture('diff');
+    const repo = await openRepository(p);
+    const original = Array.from({ length: 30 }, (_, i) => `original line ${i + 1}\n`).join('');
+    const rewritten = Array.from({ length: 30 }, (_, i) => `rewritten line ${i + 1}\n`).join('');
+    const index = repo.index();
+    await fs.writeFile(path.join(p, 'A'), original);
+    index.addPath('A');
+    const oldTree = repo.getTree(index.writeTree());
+    await fs.writeFile(path.join(p, 'A'), rewritten);
+    await fs.writeFile(path.join(p, 'A-renamed'), original);
+    index.addPath('A');
+    index.addPath('A-renamed');
+    const newTree = repo.getTree(index.writeTree());
+    const diff = repo.diffTreeToTree(oldTree, newTree);
+    diff.findSimilar({ renamesFromRewrites: true });
+    const deltas = [...diff.deltas()].map(delta => ({
+      status: delta.status(),
+      oldPath: delta.oldFile().path(),
+      newPath: delta.newFile().path(),
+    }));
+    expect(deltas).toEqual([
+      { status: 'Added', oldPath: 'A', newPath: 'A' },
+      { status: 'Renamed', oldPath: 'A', newPath: 'A-renamed' },
+    ]);
+  });
+
+  it('find renamed diff delta with renamesFromRewrites disabled', async () => {
+    const p = await useFixture('diff');
+    const repo = await openRepository(p);
+    // libgit2 falls back to `diff.renames` when no find flag is set.
+    repo.config().setBool('diff.renames', false);
+    const headTree = repo.head().peelToTree();
+    await fs.rename(path.join(p, 'A'), path.join(p, 'A-renamed'));
+    const index = repo.index();
+    index.addPath('A-renamed');
+    index.write();
+    const diff = repo.diffTreeToWorkdirWithIndex(headTree);
+    diff.findSimilar({ renames: true, renamesFromRewrites: false });
+    const deltas = [...diff.deltas()].map(delta => ({
+      status: delta.status(),
+      oldPath: delta.oldFile().path(),
+      newPath: delta.newFile().path(),
+    }));
+    expect(deltas).toEqual([{ status: 'Renamed', oldPath: 'A', newPath: 'A-renamed' }]);
+  });
 });

From 695fefe1c6a6babd55f9895c77a10b9494adc233 Mon Sep 17 00:00:00 2001
From: poketopa <lhs5427ll@gmail.com>
Date: Mon, 19 Oct 2026 18:09:31 +0900
Subject: [PATCH 2/2] fix(diff): honor renamesFromRewrites in findSimilar

DiffFindOptions.renamesFromRewrites was forwarded to
git2::DiffFindOptions::renames(), so it toggled GIT_DIFF_FIND_RENAMES
instead of GIT_DIFF_FIND_RENAMES_FROM_REWRITES. Setting it to true
never used rewritten files as rename sources, and setting it to false
cleared an explicit renames: true.

Forward it to renames_from_rewrites(), as StatusOptions already does.
---
 src/diff.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/diff.rs b/src/diff.rs
index 13a852b8..b822b72c 100644
--- a/src/diff.rs
+++ b/src/diff.rs
@@ -218,7 +218,7 @@ impl From<DiffFindOptions> for git2::DiffFindOptions {
       opts.renames(flag);
     }
     if let Some(flag) = value.renames_from_rewrites {
-      opts.renames(flag);
+      opts.renames_from_rewrites(flag);
     }
     if let Some(flag) = value.copies {
       opts.copies(flag);