fix(work): keep spaced paths from diff headers in the attempt diff canvas

server/unified_diff.py

@@ -202,6 +202,18 @@ def append_file(old_path: str = "", new_path: str = "") -> dict[str, Any] | None
 
 
 def _paths_from_diff_header(line: str) -> tuple[str, str]:
+    names = line[len("diff --git ") :]
+    if '"' not in names:
+        # Git does not quote names that only contain spaces, so a space alone
+        # cannot separate them. Split where both names denote the same path;
+        # renames and copies carry their own path lines below the header.
+        for index, char in enumerate(names):
+            if char != " ":
+                continue
+            old_path, new_path = names[:index], names[index + 1 :]
+            stripped = _without_prefix(old_path)
+            if old_path == new_path or (stripped and stripped == _without_prefix(new_path)):
+                return old_path, new_path
     try:
         parts = shlex.split(line)
     except ValueError:
@@ -211,6 +223,11 @@ def _paths_from_diff_header(line: str) -> tuple[str, str]:
     return "", ""
 
 
+def _without_prefix(path: str) -> str:
+    _, separator, rest = path.partition("/")
+    return rest if separator else ""
+
+
 def _marker_path(value: str) -> str:
     text = str(value or "").split("\t", 1)[0].strip()
     if len(text) >= 2 and text[0] == text[-1] == '"':

tests/test_unified_diff_canvas.py

@@ -136,6 +136,39 @@ def test_parse_unified_diff_keeps_marker_like_content_inside_hunks() -> None:
     assert second["deletions"] == 1
 
 
+def test_parse_unified_diff_keeps_spaced_paths_without_marker_lines() -> None:
+    parsed = parse_unified_diff(
+        "\n".join(
+            [
+                "diff --git a/old notes.txt b/old notes.txt",
+                "deleted file mode 100644",
+                "index 587be6b..0000000",
+                "--- a/old notes.txt\t",
+                "+++ /dev/null",
+                "@@ -1 +0,0 @@",
+                "-x",
+                "diff --git a/cover art.png b/cover art.png",
+                "index bdc955b..8835708 100644",
+                "Binary files a/cover art.png and b/cover art.png differ",
+                "diff --git a/run me.sh b/run me.sh",
+                "old mode 100644",
+                "new mode 100755",
+            ]
+        ),
+        changed_files=["old notes.txt", "cover art.png", "run me.sh"],
+    )
+
+    assert [(item["path"], item["status"]) for item in parsed["files"]] == [
+        ("old notes.txt", "deleted"),
+        ("cover art.png", "modified"),
+        ("run me.sh", "modified"),
+    ]
+    assert parsed["files"][0]["oldPath"] == "old notes.txt"
+    assert parsed["files"][0]["deletions"] == 1
+    assert parsed["files"][1]["oldPath"] == "cover art.png"
+    assert parsed["files"][1]["newPath"] == "cover art.png"
+
+
 def test_diff_canvas_payload_keeps_report_for_local_mode_switch() -> None:
     structured = parse_unified_diff(
         "diff --git a/a.py b/a.py\n--- a/a.py\n+++ b/a.py\n@@ -1 +1 @@\n-old\n+new\n"
@@ -188,6 +221,7 @@ def test_parse_unified_diff_caps_files_without_merging_hunks() -> None:
     test_parse_unified_diff_keeps_untracked_files_without_hunks()
     test_parse_unified_diff_renders_an_untracked_new_file_patch()
     test_parse_unified_diff_keeps_marker_like_content_inside_hunks()
+    test_parse_unified_diff_keeps_spaced_paths_without_marker_lines()
     test_diff_canvas_payload_keeps_report_for_local_mode_switch()
     test_parse_unified_diff_caps_files_without_merging_hunks()
     print("unified diff canvas tests passed")