Move f-string compilation of the expression earlier, before the conversion character and format_spec are checked. This allows for error messages that more closely match what a user would expect.

2025-07-24 11:44:31 +00:00 · 2015-09-23 07:49:00 -04:00 · 2015-09-23 07:49:00 -04:00 · 1d44c41b0c
commit 1d44c41b0c
parent 3a1a8d0424
2 changed files with 60 additions and 15 deletions
--- a/Lib/test/test_fstring.py
+++ b/Lib/test/test_fstring.py
@ -287,6 +287,15 @@ f'{a * x()}'"""
                             "f' { } '",
                             r"f'{\n}'",
                             r"f'{\n \n}'",
+
+                             # Catch the empty expression before the
+                             #  invalid conversion.
+                             "f'{!x}'",
+                             "f'{ !xr}'",
+                             "f'{!x:}'",
+                             "f'{!x:a}'",
+                             "f'{ !xr:}'",
+                             "f'{ !xr:a}'",
                             ])

    def test_parens_in_expressions(self):