https://github.com/python/cpython/commit/60cfc6d1ae01c89f9b390ea5eb6a582c8a5... commit: 60cfc6d1ae01c89f9b390ea5eb6a582c8a53f971 branch: main author: Pablo Galindo Salgado <Pablogsal@gmail.com> committer: pablogsal <Pablogsal@gmail.com> date: 2023-05-31T22:01:29+01:00 summary: Clarify that error messages are better with PEP 701 (#105150) Co-authored-by: Marta Gómez Macías <mgmacias@google.com> files: M Doc/whatsnew/3.12.rst diff --git a/Doc/whatsnew/3.12.rst b/Doc/whatsnew/3.12.rst index 2423672f75b3..6f725906f1e1 100644 --- a/Doc/whatsnew/3.12.rst +++ b/Doc/whatsnew/3.12.rst @@ -203,6 +203,31 @@ same quote as the containing f-string. Let's cover these in detail: See :pep:`701` for more details. +As a positive side-effect of how this feature has been implemented (by parsing f-strings +with the PEG parser (see :pep:`617`), now error messages for f-strings are more precise +and include the exact location of the error. For example, in Python 3.11, the following +f-string raises a :exc:`SyntaxError`: + +.. code-block:: python + + >>> my_string = f"{x z y}" + f"{1 + 1}" + File "<stdin>", line 1 + (x z y) + ^^^ + SyntaxError: f-string: invalid syntax. Perhaps you forgot a comma? + +but the error message doesn't include the exact location of the error withing the line and +also has the expression artificially surrounded by parentheses. In Python 3.12, as f-strings +are parsed with the PEG parser, error messages can be more precise and show the entire line: + +.. code-block:: python + + >>> my_string = f"{x z y}" + f"{1 + 1}" + File "<stdin>", line 1 + my_string = f"{x z y}" + f"{1 + 1}" + ^^^ + SyntaxError: invalid syntax. Perhaps you forgot a comma? + (Contributed by Pablo Galindo, Batuhan Taskaya, Lysandros Nikolaou, Cristián Maureira-Fredes and Marta Gómez in :gh:`102856`. PEP written by Pablo Galindo, Batuhan Taskaya, Lysandros Nikolaou and Marta Gómez).