Fix #3659: Normalize [C] and [c] to (c) in copyright detection

- Normalize [C] and [c] before bracket removal in prepare_text_line()
- Add tests for both [C] and [c] variants

Author: levi42x

src/cluecode/copyrights.py

@@ -4502,6 +4502,11 @@ def prepare_text_line(line):
 
         # normalize copyright signs, quotes and spacing around them
         .replace('"Copyright', '" Copyright')
+        
+        # normalize [C] and [c] to (c) before bracket removal
+        .replace('[C]', '(c)')
+        .replace('[c]', '(c)')
+        
         .replace('( C)', ' (c) ')
         .replace('(C)', ' (c) ')
         .replace('(c)', ' (c) ')

tests/cluecode/test_copyrights_basic.py

@@ -68,6 +68,16 @@ def test_prepare_text_line_does_not_damage_urls(self):
         result = prepare_text_line(cp)
         assert result == 'copyright (c) 2000 World Wide Web Consortium, http://www.w3.org'
 
+    def test_prepare_text_line_normalizes_bracket_C_uppercase(self):
+        cp = '[C] The Regents of the University of Michigan and Merit Network, Inc. 1992, 1993, 1994, 1995 All Rights Reserved'
+        result = prepare_text_line(cp)
+        assert result == '(c) The Regents of the University of Michigan and Merit Network, Inc. 1992, 1993, 1994, 1995 All Rights Reserved'
+
+    def test_prepare_text_line_normalizes_bracket_c_lowercase(self):
+        cp = 'Copyright [c] 2023 Example Company'
+        result = prepare_text_line(cp)
+        assert result == 'Copyright (c) 2023 Example Company'
+
     def test_prepare_text_line_does_replace_copyright_signs(self):
         cp = 'Copyright \\A9 1991, 1999 Free Software Foundation, Inc.'
         result = prepare_text_line(cp)