fetchart: handle FilesystemError when setting album art

When set_art encounters a permissions error or cross-device move failure
(e.g. file locked by foobar2000 on Windows), the unhandled
FilesystemError crashes the import or the fetchart CLI command.

Wrap both _set_art call sites in try/except FilesystemError, matching
the pattern already used in the cleanup method (line ~520). On failure,
log a warning and continue instead of aborting.

Fixes #6193.

Author: lawrence3699

beetsplug/fetchart.py

@@ -1525,7 +1525,11 @@ def assign_art(self, session: ImportSession, task: ImportTask):
             candidate = self.art_candidates.pop(task)
             removal_enabled = self._is_source_file_removal_enabled()
 
-            self._set_art(task.album, candidate, not removal_enabled)
+            try:
+                self._set_art(task.album, candidate, not removal_enabled)
+            except util.FilesystemError as exc:
+                self._log.warning("error setting art: {}", exc)
+                return  # No art was set, so skip the prune step below.
 
             if removal_enabled and not self._is_candidate_fallback(candidate):
                 task.prune(candidate.path)
@@ -1629,8 +1633,13 @@ def batch_fetch_art(
 
                 candidate = self.art_for_album(album, local_paths)
                 if candidate:
-                    self._set_art(album, candidate)
-                    message = colorize("text_success", "found album art")
+                    try:
+                        self._set_art(album, candidate)
+                    except util.FilesystemError as exc:
+                        self._log.warning("error setting art: {}", exc)
+                        message = colorize("text_error", "error setting art")
+                    else:
+                        message = colorize("text_success", "found album art")
                 else:
                     message = colorize("text_error", "no art found")
                 ui.print_(f"{album}: {message}")

test/plugins/test_fetchart.py

@@ -16,6 +16,7 @@
 import ctypes
 import os
 import sys
+from unittest.mock import patch
 
 from beets import util
 from beets.test.helper import IOMixin, PluginTestCase
@@ -119,6 +120,43 @@ def test_colorization(self):
         out = self.run_with_output("fetchart")
         assert " - the älbum: \x1b[1;31mno art found\x1b[39;49;00m\n" == out
 
+    def test_batch_fetch_filesystem_error(self):
+        """When _set_art raises FilesystemError (e.g. permissions), the
+        fetchart command should log a warning instead of crashing."""
+        self.touch(b"c\xc3\xb6ver.jpg", dir=self.album.path, content="IMAGE")
+
+        exc = util.FilesystemError(
+            reason=PermissionError("mocked permission error"),
+            verb="move",
+            paths=[b"/src", b"/dst"],
+        )
+        with patch(
+            "beetsplug.fetchart.FetchArtPlugin._set_art",
+            side_effect=exc,
+        ):
+            out = self.run_with_output("fetchart")
+
+        assert "error setting art" in out
+
+    def test_assign_art_filesystem_error(self):
+        """When _set_art raises FilesystemError during import, the import
+        should continue instead of crashing."""
+        exc = util.FilesystemError(
+            reason=PermissionError("mocked permission error"),
+            verb="move",
+            paths=[b"/src", b"/dst"],
+        )
+        fa = FetchArtPlugin()
+        # Simulate an import task with a queued candidate
+        task = type("FakeTask", (), {"album": self.album})()
+        fa.art_candidates[task] = type(
+            "FakeCandidate", (), {"path": b"/tmp/art.jpg", "source_name": "test"}
+        )()
+
+        with patch.object(fa, "_set_art", side_effect=exc):
+            # Should not raise
+            fa.assign_art(session=None, task=task)
+
     def test_sources_is_a_string(self):
         self.config["fetchart"].set({"sources": "filesystem"})
         fa = FetchArtPlugin()