Add support for sorting baseline output

mypy_baseline/_config.py

@@ -29,6 +29,7 @@ class Config:
     depth: int = 40
     allow_unsynced: bool = False
     preserve_position: bool = False
+    sort_baseline: bool = False
     hide_stats: bool = False
     no_colors: bool = bool(os.environ.get('NO_COLOR'))
     ignore: list[str] = dataclasses.field(default_factory=list)
@@ -68,6 +69,10 @@ def init_parser(self, parser: ArgumentParser) -> None:
             '--preserve-position', action='store_true',
             help='do not remove line number from the baseline.',
         )
+        add(
+            '--sort-baseline', action='store_true',
+            help='sort the baseline file.',
+        )
         add(
             '--hide-stats', action='store_true',
             help='do not show stats at the end.',

mypy_baseline/commands/_sync.py

@@ -28,6 +28,9 @@ def run(self) -> int:
             clean_line = error.get_clean_line(self.config)
             new_baseline.append(clean_line)
 
+        if self.config.sort_baseline:
+            new_baseline.sort()
+
         synced = False
         if old_baseline:
             synced = self._stable_sync(old_baseline, new_baseline)
@@ -44,9 +47,13 @@ def _stable_sync(self, old_bline: list[str], new_bline: list[str]) -> bool:
         Currently, we can do a stable sync only when there are no new lines added.
         It's hard to insert new lines in the correct positions, and adding them
         at the end of the file will cause merge conflicts.
-        Sorting lines alphabetically would solve the issue, but I want to keep
-        backward compatibility.
+        Sorting lines solves the issue, so we don't use stable sync when the output
+        is sorted.
+        However, sorting is not enabled by default because I want to keep backward
+        compatibility.
         """
+        if not self.config.sort_baseline:
+            return False
         old_set = set(old_bline)
         new_set = set(new_bline)
         removed = old_set - new_set

tests/test_commands/test_sync.py

@@ -34,3 +34,19 @@ def test_sync_notebook(tmp_path: Path):
     actual = blpath.read_text()
     line1 = actual.splitlines()[0]
     assert line1 == 'fail.ipynb:cell_1:0: error: Incompatible return value type (got "int", expected "str")  [return-value]'  # noqa: E501
+
+
+def test_sync_sorted(tmp_path: Path):
+    blpath = tmp_path / 'bline.txt'
+    stdin = StringIO()
+    stdin.write(LINE1)
+    stdin.write(LINE2)
+    stdin.write(LINE3)
+    stdin.seek(0)
+    code = main(['sync', '--sort-baseline', '--baseline-path', str(blpath)], stdin, StringIO())  # noqa: E501
+    assert code == 0
+    actual = blpath.read_text()
+    line1, line2, line3 = actual.splitlines()
+    assert line1 == 'python/utils.py:0: error: Second argument of Enum() must be string  [misc]'  # noqa: E501s
+    assert line2 == 'settings.py:0: error: How are you?  [union-attr]'
+    assert line3 == 'views.py:0: error: Hello world  [assignment]'