fix: do not delete .mp3 file remuxed from MPEGLAYER3 WAV

beets/util/extension.py

@@ -170,7 +170,11 @@ def remux_mpeglayer3_wav(path: AnyPath) -> AnyPath | None:
     mp3_path = syspath.with_suffix(".mp3")
     mp3_path.write_bytes(mp3_data)
 
-    util.remove(path)
+    # When the source is already named `.mp3`, it has just been rewritten in
+    # place with the extracted stream, so there is no separate original left
+    # to remove.
+    if mp3_path != syspath:
+        util.remove(path)
 
     if isinstance(path, str):
         return str(mp3_path)

docs/changelog.rst

@@ -95,6 +95,9 @@ Bug fixes
   valid date/time string" error instead of crashing with an uncaught
   ``KeyError``. A ``|`` was being accepted as a relative-date unit due to a
   regular expression character-class typo.
+- ``remux_mp3_in_wav`` no longer deletes the imported file when a
+  MPEGLAYER3 WAV is named ``.mp3``: the remuxed stream was written back to the
+  same path and then removed as if it were a leftover original. :bug:`6748`
 
 ..
     For plugin developers

test/test_importer.py

@@ -1894,6 +1894,17 @@ def test_remux_mpeglayer3_wav(self):
         assert mp3_path.exists()
         assert not dest.exists()
 
+    def test_remux_mpeglayer3_wav_mp3_extension(self):
+        """A MPEGLAYER3 WAV named `.mp3` must not be deleted (#6748)."""
+        src = _common.RSRC / "mpeglayer3.wav"
+        dest = self.temp_path / "mpeglayer3.mp3"
+        shutil.copy(syspath(src), syspath(dest))
+
+        mp3_path = remux_mpeglayer3_wav(dest)
+
+        assert mp3_path == dest
+        assert dest.exists()
+
     def test_remux_mpeglayer3_wav_disabled(self):
         """When remux_mp3_in_wav is disabled, WAV file should not be remuxed."""
         self.config["import"]["remux_mp3_in_wav"] = False