Merge pull request #21 from n-takumasa/_warn_unused

mnt: fix #20

jsonc/_add_comments.py

@@ -3,6 +3,7 @@
 import copy
 import io
 import json
+import os
 import sys
 import warnings
 from tokenize import COMMENT, NL, STRING, TokenInfo, generate_tokens, untokenize
@@ -12,6 +13,8 @@
     CommentsDict = dict[str, "Comments"] | dict[int, "Comments"]
     Comments = str | CommentsDict | tuple[str, CommentsDict]
 
+_warn_skips = (os.path.dirname(__file__),)  # noqa: PTH120
+
 
 def _make_comment(text: str, indent=0) -> str:
     return "\n".join(
@@ -46,17 +49,11 @@ def _warn_unused(
     if full_key:
         full_key += "."
     for k in comments:
-        f = sys._getframe()  # noqa: SLF001
-        filename = f.f_code.co_filename
-        stacklevel = 2
-        while f := f.f_back:
-            if f.f_code.co_filename != filename:
-                break
-            stacklevel += 1
-        warnings.warn(
-            "Unused comment with key: " + full_key + str(k),
-            stacklevel=4,
-        )
+        msg = f"Unused comment with key: {full_key}{k}"
+        if sys.version_info >= (3, 12):
+            warnings.warn(msg, stacklevel=2, skip_file_prefixes=_warn_skips)
+        else:
+            warnings.warn(msg, stacklevel=4)
 
 
 def _add_comments(data: str, comments: Comments) -> str:  # noqa: C901

tests/test_warn.py

@@ -0,0 +1,11 @@
+from pathlib import Path
+
+import pytest
+
+import jsonc
+
+
+def test_unused():
+    with pytest.warns(UserWarning, match="Unused comment with key: warn") as w:
+        jsonc.dumps({}, indent=2, comments={"warn": "spam"})
+        assert Path(w.list[0].filename).absolute() == Path(__file__).absolute()