Specify illegal character(s) found and respective attribute(s)

nomenclature/codelist.py

@@ -339,28 +339,28 @@ def check_illegal_characters(self, config: NomenclatureConfig) -> dict[str, Code
         illegal = ["{", "}"] + config.illegal_characters
         errors = ErrorCollector()
 
-        def _check_string(value):
+        def _check_string(attr, value):
             if isinstance(value, str):
-                if any(char in value for char in illegal):
+                if found := set(illegal).intersection(value):
+                    found = "', '".join(sorted(found))
                     errors.append(
                         ValueError(
-                            f"Unexpected character in {self.name}: '{code.name}'."
+                            f"Unexpected character(s) '{found}' in {self.name}.{attr} of: '{code.name}'."
                             " Check for illegal characters and/or if tags were spelled correctly."
                         )
                     )
             elif isinstance(value, dict):
-                for k in value.keys():
-                    _check_string(k)
-                for v in value.values():
-                    _check_string(v)
+                for k, v in value.items():
+                    _check_string(k, k)
+                    _check_string(k, v)
             elif isinstance(value, list):
                 for item in value:
-                    _check_string(item)
+                    _check_string(attr, item)
 
         for code in self.mapping.values():
             if not code.repository:
-                for value in code.model_dump(exclude="file").values():
-                    _check_string(value)
+                for attr, value in code.model_dump(exclude="file").items():
+                    _check_string(attr, value)
         if errors:
             raise ValueError(errors)
 

tests/test_codelist.py

@@ -271,9 +271,18 @@ def test_to_csv():
 @pytest.mark.parametrize(
     "subfolder, match",
     [
-        ("tag_in_str", r"Unexpected character in variable: 'Primary Energy\|{Feul}'"),
-        ("tag_in_list", r"Unexpected character in variable: 'Share\|Coal'"),
-        ("tag_in_dict", r"Unexpected character in variable: 'Primary Energy'"),
+        (
+            "tag_in_str",
+            r"Unexpected character\(s\) '{', '}' in variable.name of: 'Primary Energy\|{Feul}'",
+        ),
+        (
+            "tag_in_list",
+            r"Unexpected character\(s\) '{' in variable.info of: 'Share\|Coal'",
+        ),
+        (
+            "tag_in_dict",
+            r"Unexpected character\(s\) '}' in variable.invalid of: 'Primary Energy'",
+        ),
     ],
 )
 def test_stray_tag_fails(subfolder, match):
@@ -287,7 +296,9 @@ def test_stray_tag_fails(subfolder, match):
 
 def test_illegal_char_fails():
     """Check that illegal character raises expected error."""
-    match = r"Unexpected character in variable: 'Primary Energy\|Coal'"
+    match = (
+        r"Unexpected character\(s\) '\"' in variable.info of: 'Primary Energy\|Coal'"
+    )
     with raises(ValueError, match=match):
         DataStructureDefinition(
             MODULE_TEST_DATA_DIR / "illegal_chars" / "char_in_str" / "definitions"