Fix indentation change to comments when using --fix (#4273)

.github/workflows/tox.yml

@@ -72,7 +72,7 @@ jobs:
     env:
       # Number of expected test passes, safety measure for accidental skip of
       # tests. Update value if you add/remove tests.
-      PYTEST_REQPASS: 887
+      PYTEST_REQPASS: 888
     steps:
       - uses: actions/checkout@v4
         with:

src/ansiblelint/yaml_utils.py

@@ -1206,6 +1206,11 @@ def _post_process_yaml(
 
                 full_line_comments.append((i, stripped))
             elif full_line_comments:
+                # match ident of previous non-blank line
+                if not lines[i - 1].lstrip():
+                    prev = lines[i - 2]
+                    space_length = len(prev) - len(prev.lstrip())
+
                 # end of full line comments so adjust to match indent of this line
                 spaces = " " * space_length
                 for index, comment in full_line_comments:

test/test_yaml_utils.py

@@ -243,6 +243,12 @@ def load_yaml_formatting_fixtures(fixture_filename: str) -> tuple[str, str, str]
         pytest.param("---\nfoo: YES\n", "---\nfoo: true\n", (1, 1), id="9"),
         pytest.param("---\nfoo: YES\n", "---\nfoo: YES\n", (1, 2), id="10"),
         pytest.param("---\nfoo: YES\n", "---\nfoo: YES\n", None, id="11"),
+        pytest.param(
+            "---\n  # quoted-strings:\n  #   quote-type: double\n  #   required: only-when-needed\n\nignore:\n  - secrets.yml\n",
+            "---\n  # quoted-strings:\n  #   quote-type: double\n  #   required: only-when-needed\n\nignore:\n  - secrets.yml\n",
+            None,
+            id="12",
+        ),
     ),
 )
 def test_fmt(before: str, after: str, version: tuple[int, int] | None) -> None: