pythongh-113703: Correctly identify incomplete f-strings in the codeop module (python#113709)

Author: pablogsal

Lib/test/test_codeop.py

@@ -223,6 +223,9 @@ def test_incomplete(self):
         ai("(x for x in")
         ai("(x for x in (")
 
+        ai('a = f"""')
+        ai('a = \\')
+
     def test_invalid(self):
         ai = self.assertInvalid
         ai("a b")

Misc/NEWS.d/next/Core and Builtins/2024-01-04-17-15-30.gh-issue-113703.Zsk0pY.rst

@@ -0,0 +1,2 @@
+Fix a regression in the :mod:`codeop` module that was causing it to incorrectly
+identify incomplete f-strings. Patch by Pablo Galindo

Parser/lexer/lexer.c

@@ -1355,9 +1355,13 @@ tok_get_fstring_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct
             tok->lineno = the_current_tok->f_string_line_start;
 
             if (current_tok->f_string_quote_size == 3) {
-                return MAKE_TOKEN(_PyTokenizer_syntaxerror(tok,
+                _PyTokenizer_syntaxerror(tok,
                                     "unterminated triple-quoted f-string literal"
-                                    " (detected at line %d)", start));
+                                    " (detected at line %d)", start);
+                if (c != '\n') {
+                    tok->done = E_EOFS;
+                }
+                return MAKE_TOKEN(ERRORTOKEN);
             }
             else {
                 return MAKE_TOKEN(_PyTokenizer_syntaxerror(tok,