Handle None values when doing conversions and catch indexing errors

comictaggerlib/filerenamer.py

@@ -73,6 +73,8 @@ class MetadataFormatter(string.Formatter):
         return cast(str, super().format_field(value, format_spec))
 
     def convert_field(self, value: Any, conversion: str | None) -> str:
+        if value is None:
+            return ""
         if isinstance(value, Iterable) and not isinstance(value, (str, tuple)):
             if conversion == "C":
                 if isinstance(value, Sized):
@@ -182,8 +184,11 @@ class MetadataFormatter(string.Formatter):
 
                 # given the field_name, find the object it references
                 #  and the argument it came from
-                obj, arg_used = self.get_field(field_name, args, kwargs)
-                used_args.add(arg_used)
+                try:
+                    obj, arg_used = self.get_field(field_name, args, kwargs)
+                    used_args.add(arg_used)
+                except Exception:
+                    obj = None
 
                 obj = self.none_replacement(obj, replacement, r)
                 # do any conversion on the resulting object

testing/filenames.py

@@ -1114,6 +1114,22 @@ for p in names:
         )
 
 file_renames = [
+    (
+        "{series} #{issue} - {title} ({year}) ({price!c})",  # conversion on None
+        False,
+        False,
+        "universal",
+        "Cory Doctorow's Futuristic Tales of the Here and Now #001 - Anda's Game (2007).cbz",
+        does_not_raise(),
+    ),
+    (
+        "{country[0]} {price} {year}",  # Indexing a None value
+        False,
+        False,
+        "universal",
+        "2007.cbz",
+        does_not_raise(),
+    ),
     (
         "{series!c} {price} {year}",  # Capitalize
         False,