Fix the TypeError when import.set_fields is provided non-string values (#5495)

Fixes #4840 by converting input values to strings before they are used.
Modifies the test cases for ``set_fields`` to appropriately test this
behavior.

Author: snejus

beets/importer.py

@@ -605,7 +605,7 @@ def set_fields(self, lib):
         """
         items = self.imported_items()
         for field, view in config["import"]["set_fields"].items():
-            value = view.get()
+            value = str(view.get())
             log.debug(
                 "Set field {1}={2} for {0}",
                 displayable_path(self.paths),
@@ -1062,7 +1062,7 @@ def set_fields(self, lib):
         values, for the singleton item.
         """
         for field, view in config["import"]["set_fields"].items():
-            value = view.get()
+            value = str(view.get())
             log.debug(
                 "Set field {1}={2} for {0}",
                 displayable_path(self.paths),

docs/changelog.rst

@@ -51,6 +51,7 @@ Bug fixes:
   that it no longer treats "and" and "or" queries the same. To maintain
   previous behaviour add commas between your query keywords. For help see
   :ref:`combiningqueries`.
+* Fix the ``TypeError`` when :ref:`set_fields` is provided non-string values. :bug:`4840`
 
 For packagers:
 

test/test_importer.py

@@ -395,11 +395,13 @@ def test_import_single_files(self):
     def test_set_fields(self):
         genre = "\U0001f3b7 Jazz"
         collection = "To Listen"
+        disc = 0
 
         config["import"]["set_fields"] = {
             "collection": collection,
             "genre": genre,
             "title": "$title - formatted",
+            "disc": disc,
         }
 
         # As-is item import.
@@ -412,6 +414,7 @@ def test_set_fields(self):
             assert item.genre == genre
             assert item.collection == collection
             assert item.title == "Tag Track 1 - formatted"
+            assert item.disc == disc
             # Remove item from library to test again with APPLY choice.
             item.remove()
 
@@ -426,6 +429,7 @@ def test_set_fields(self):
             assert item.genre == genre
             assert item.collection == collection
             assert item.title == "Applied Track 1 - formatted"
+            assert item.disc == disc
 
 
 class ImportTest(ImportTestCase):
@@ -583,12 +587,14 @@ def test_set_fields(self):
         genre = "\U0001f3b7 Jazz"
         collection = "To Listen"
         comments = "managed by beets"
+        disc = 0
 
         config["import"]["set_fields"] = {
             "genre": genre,
             "collection": collection,
             "comments": comments,
             "album": "$album - formatted",
+            "disc": disc,
         }
 
         # As-is album import.
@@ -608,6 +614,7 @@ def test_set_fields(self):
                     item.get("album", with_album=False)
                     == "Tag Album - formatted"
                 )
+                assert item.disc == disc
             # Remove album from library to test again with APPLY choice.
             album.remove()
 
@@ -629,6 +636,7 @@ def test_set_fields(self):
                     item.get("album", with_album=False)
                     == "Applied Album - formatted"
                 )
+                assert item.disc == disc
 
 
 class ImportTracksTest(ImportTestCase):