Handle list fields in rewrite

Author: snejus

beetsplug/advancedrewrite.py

@@ -26,6 +26,8 @@
 from beets.plugins import BeetsPlugin
 from beets.ui import UserError
 
+from .rewrite import apply_rewrite_rules
+
 
 def rewriter(field, simple_rules, advanced_rules):
     """Template field function factory.
@@ -38,10 +40,10 @@ def rewriter(field, simple_rules, advanced_rules):
 
     def fieldfunc(item):
         value = item._values_fixed[field]
-        for pattern, replacement in simple_rules:
-            if pattern.match(value.lower()):
-                # Rewrite activated.
-                return replacement
+        if (new_value := apply_rewrite_rules(value, simple_rules)) != value:
+            # Rewrite activated.
+            return new_value
+
         for query, replacement in advanced_rules:
             if query.match(item):
                 # Rewrite activated.

beetsplug/rewrite.py

@@ -18,10 +18,44 @@
 
 import re
 from collections import defaultdict
+from functools import singledispatch
+from typing import Any, TypeVar
 
 from beets import library, ui
 from beets.plugins import BeetsPlugin
 
+T = TypeVar("T")
+
+
+@singledispatch
+def rewrite_value(value: Any, pat: re.Pattern[str], repl: str) -> Any:
+    """Rewrite a value if it matches the given pattern."""
+    return value
+
+
+@rewrite_value.register
+def _(value: str, pat: re.Pattern[str], repl: str) -> str:
+    if pat.match(value.lower()):
+        return repl
+    return value
+
+
+@rewrite_value.register(list)
+def _(value: list[str], pat: re.Pattern[str], repl: str) -> list[str]:
+    return [rewrite_value(v, pat, repl) for v in value]
+
+
+def apply_rewrite_rules(
+    value: T, rules: list[tuple[re.Pattern[str], str]]
+) -> T:
+    """Apply the first matching rewrite rule to the given value."""
+    for pattern, replacement in rules:
+        if (new_value := rewrite_value(value, pattern, replacement)) != value:
+            # Rewrite activated.
+            return new_value
+    # Not activated; return original value.
+    return value
+
 
 def rewriter(field, rules):
     """Create a template field function that rewrites the given field
@@ -30,13 +64,7 @@ def rewriter(field, rules):
     """
 
     def fieldfunc(item):
-        value = item._values_fixed[field]
-        for pattern, replacement in rules:
-            if pattern.match(value.lower()):
-                # Rewrite activated.
-                return replacement
-        # Not activated; return original value.
-        return value
+        return apply_rewrite_rules(item._values_fixed[field], rules)
 
     return fieldfunc
 

test/plugins/test_advancedrewrite.py

@@ -37,9 +37,6 @@ def test_simple_rewrite_example(self):
 
             assert item.artist == "이달의 소녀 오드아이써클"
 
-    @pytest.mark.xfail(
-        reason="advancedrewrite currently assumes scalar field values",
-    )
     def test_list_field(self):
         with self.configure_plugin([{"genres rock": "techno"}]):
             item = self.add_item(genres=["rock", "pop"])

test/plugins/test_rewrite.py

@@ -52,9 +52,6 @@ def test_rewrite_is_case_insensitive_and_leaves_non_matches_unchanged(
             assert matching_item.artist == "LOONA / ODD EYE CIRCLE"
             assert other_item.artist == "ARTMS"
 
-    @pytest.mark.xfail(
-        reason="rewrite currently assumes scalar field values",
-    )
     def test_genres_rewrite_applies_to_matching_list_values(self):
         with self.configure_plugin({"genres rock": "Classic Rock"}):
             item = self.add_item(genres=["rock", "pop"])