fix(work): read copy headers in the attempt diff canvas

server/unified_diff.py

@@ -109,6 +109,15 @@ def append_file(old_path: str = "", new_path: str = "") -> dict[str, Any] | None
             current_file["newPath"] = raw_line[len("rename to ") :].strip()
             current_file["path"] = current_file["newPath"]
             continue
+        if raw_line.startswith("copy from "):
+            current_file["status"] = "copied"
+            current_file["oldPath"] = raw_line[len("copy from ") :].strip()
+            continue
+        if raw_line.startswith("copy to "):
+            current_file["status"] = "copied"
+            current_file["newPath"] = raw_line[len("copy to ") :].strip()
+            current_file["path"] = current_file["newPath"]
+            continue
 
         hunk_match = _HUNK_HEADER.match(raw_line)
         if hunk_match:

tests/test_unified_diff_canvas.py

@@ -241,6 +241,48 @@ def test_parse_unified_diff_splits_hunk_lines_only_at_newlines() -> None:
     ]
 
 
+def test_parse_unified_diff_reads_copy_headers() -> None:
+    # Output of `git -c diff.renames=copies diff HEAD` after copying a
+    # modified file: an exact copy has no marker lines or hunks.
+    parsed = parse_unified_diff(
+        "\n".join(
+            [
+                "diff --git a/my src.txt b/my dup.txt",
+                "similarity index 100%",
+                "copy from my src.txt",
+                "copy to my dup.txt",
+                "diff --git a/lib.py b/lib copy.py",
+                "similarity index 80%",
+                "copy from lib.py",
+                "copy to lib copy.py",
+                "index 01e79c3..94ebaf9 100644",
+                "--- a/lib.py",
+                "+++ b/lib copy.py",
+                "@@ -1 +1,2 @@",
+                " base",
+                "+copy",
+                "diff --git a/my src.txt b/my src.txt",
+                "index b566061..b13f895 100644",
+                "--- a/my src.txt",
+                "+++ b/my src.txt",
+                "@@ -1 +1,2 @@",
+                " base",
+                "+source",
+            ]
+        ),
+        changed_files=["my dup.txt", "lib copy.py", "my src.txt"],
+    )
+
+    assert [
+        (item["path"], item["oldPath"], item["newPath"], item["status"], item["additions"])
+        for item in parsed["files"]
+    ] == [
+        ("my dup.txt", "my src.txt", "my dup.txt", "copied", 0),
+        ("lib copy.py", "lib.py", "lib copy.py", "copied", 1),
+        ("my src.txt", "my src.txt", "my src.txt", "modified", 1),
+    ]
+
+
 if __name__ == "__main__":
     test_parse_unified_diff_preserves_dual_line_numbers()
     test_parse_unified_diff_keeps_untracked_files_without_hunks()
@@ -250,4 +292,5 @@ def test_parse_unified_diff_splits_hunk_lines_only_at_newlines() -> None:
     test_diff_canvas_payload_keeps_report_for_local_mode_switch()
     test_parse_unified_diff_caps_files_without_merging_hunks()
     test_parse_unified_diff_splits_hunk_lines_only_at_newlines()
+    test_parse_unified_diff_reads_copy_headers()
     print("unified diff canvas tests passed")

tests/test_work_artifact_registry.py

@@ -380,6 +380,53 @@ async def run() -> None:
     asyncio.run(run())
 
 
+def test_attempt_diff_lists_committed_copies_once_with_copy_detection() -> None:
+    async def run() -> None:
+        with tempfile.TemporaryDirectory(prefix="work_artifact_copy_") as temp:
+            root = Path(temp) / "project"
+            root.mkdir()
+            _git(root, "init")
+            _git(root, "config", "user.email", "amadeus-test@example.invalid")
+            _git(root, "config", "user.name", "Amadeus Test")
+            source = root / "my src.txt"
+            source.write_text("one\ntwo\nthree\n", encoding="utf-8")
+            _git(root, "add", ".")
+            _git(root, "commit", "-m", "baseline")
+            _git(root, "config", "diff.renames", "copies")
+
+            store = WorkLedgerStore(Path(temp) / "ledger.sqlite3")
+            project = store.create_or_get_project(root)
+            item = store.create_work_item(project.project_id, title="Copy notes")
+            attempt = store.create_attempt(item.work_item_id, provider="codex", task="Copy notes")
+            registry = WorkArtifactRegistry(store)
+            await registry.capture_baseline(attempt, item)
+            (root / "my dup.txt").write_text("one\ntwo\nthree\n", encoding="utf-8")
+            source.write_text("one\ntwo\nthree\nfour\n", encoding="utf-8")
+            _git(root, "add", ".")
+            _git(root, "commit", "-m", "provider commit")
+
+            current_attempt = store.get_attempt(attempt.attempt_id)
+            assert current_attempt is not None
+            delta = await registry.finalize_attempt(current_attempt, item)
+            store.close()
+
+        assert "copy to my dup.txt" in delta["committed_patch"]
+        parsed = parse_unified_diff(
+            delta["patch"],
+            changed_files=delta["changed_files"],
+            untracked=delta["untracked"],
+        )
+        assert [
+            (entry["path"], entry["oldPath"], entry["status"], entry["additions"])
+            for entry in parsed["files"]
+        ] == [
+            ("my dup.txt", "my src.txt", "copied", 0),
+            ("my src.txt", "my src.txt", "modified", 1),
+        ]
+
+    asyncio.run(run())
+
+
 def test_non_git_workspace_registers_new_files_without_claiming_preexisting_changes() -> None:
     async def run() -> None:
         with tempfile.TemporaryDirectory(prefix="work_artifact_filesystem_") as temp:
@@ -610,6 +657,7 @@ def _main() -> None:
     test_non_ascii_entry_revision_is_registered_as_the_real_path()
     test_non_git_workspace_registers_new_files_without_claiming_preexisting_changes()
     test_explicit_amend_may_change_predecessor_owned_dirty_artifact()
+    test_attempt_diff_lists_committed_copies_once_with_copy_detection()
     print("ok: work artifact registry preserves attempt Git boundaries")