Handle raw strings with r and R in action helper (python#200)

Author: isidentical

Lib/test/test_fstring.py

@@ -884,6 +884,20 @@ def test_fstring_backslash_before_double_bracket(self):
         self.assertEqual(fr'\}}{1+1}', '\\}2')
         self.assertEqual(fr'{1+1}\}}', '2\\}')
 
+    def test_fstring_backslash_prefix_raw(self):
+        self.assertEqual(f'\\', '\\')
+        self.assertEqual(f'\\\\', '\\\\')
+        self.assertEqual(fr'\\', r'\\')
+        self.assertEqual(fr'\\\\', r'\\\\')
+        self.assertEqual(rf'\\', r'\\')
+        self.assertEqual(rf'\\\\', r'\\\\')
+        self.assertEqual(Rf'\\', R'\\')
+        self.assertEqual(Rf'\\\\', R'\\\\')
+        self.assertEqual(fR'\\', R'\\')
+        self.assertEqual(fR'\\\\', R'\\\\')
+        self.assertEqual(FR'\\', R'\\')
+        self.assertEqual(FR'\\\\', R'\\\\')
+
     def test_fstring_format_spec_greedy_matching(self):
         self.assertEqual(f"{1:}}}", "1}")
         self.assertEqual(f"{1:>3{5}}}}", "                                  1}")

Parser/action_helpers.c

@@ -1405,7 +1405,7 @@ deal_with_gstring2(Parser *p, Token* a, asdl_expr_seq* raw_expressions, Token*b)
         return NULL;
     }
 
-    int is_raw = strchr(quote_str, 'r') != NULL;
+    int is_raw = strpbrk(quote_str, "rR") != NULL;
     const char* _str = PyBytes_AsString(b->bytes);
     if (_str == NULL) {
         return NULL;