Issue 6976 - Ignore invalid headers instead of crashing

tests/test_parser.py

 # This file is part of Adblock Plus <https://adblockplus.org/>,
 # Copyright (C) 2006-present eyeo GmbH
 #
 # Adblock Plus is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 3 as
 # published by the Free Software Foundation.
 #
 # Adblock Plus is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
@@ skipping 146 matching lines @@
     with pytest.raises(ParseError):
         parse_line('%foo bar%')
 
 
 def test_parse_start():
     # Header-line lines are headers.
     assert parse_line('[Adblock Plus 1.1]', 'start').type == 'header'
     # Even if they have extra characters around.
     assert parse_line('foo[Adblock Plus 1.1] bar', 'start').type == 'header'
 
-    with pytest.raises(ParseError):
-        # But the inside of the header needs to be right.
-        parse_line('[Adblock Minus 1.1]', 'start').type
-
-    with pytest.raises(ParseError):
-        # Really right!
-        parse_line('[Adblock 1.1]', 'start')
+    # But the inside of the header needs to be right.
+    assert parse_line('[Adblock Minus 1.1]', 'start').type == 'filter'
+    # Really right!
+    assert parse_line('[Adblock 1.1]', 'start').type == 'filter'
+    # Otherwise it's just considered a filter.
 
     # Metadata-like lines are metadata.
     assert parse_line('! Foo: bar', 'metadata').type == 'metadata'
 
 
 def test_parse_metadata():
     # Header-like lines are just filters.
     assert parse_line('[Adblock 1.1]', 'metadata').type == 'filter'
     # Metadata-like lines are metadata.
     assert parse_line('! Foo: bar', 'metadata').type == 'metadata'
@@ skipping 36 matching lines @@
 def test_exception_timing():
     result = parse_filterlist(['! good line', '%bad line%'])
     assert next(result) == Comment('good line')
     with pytest.raises(ParseError):
         next(result)
 
 
 def test_parse_line_bytes():
     line = parse_line(b'! \xc3\xbc')
     assert line.text == '\xfc'