Feature or enhancement

Proposal:

Up until Python 3.11, the output of the following ast.parse/unparse run

import ast
from sys import version_info as vi

print(f"{vi.major}.{vi.minor}.{vi.micro}")
print(ast.unparse(ast.parse("f\"{'.' * 5}\"")))

was

3.11.11
f"{'.' * 5}"

In Python 3.12, new f-string features were introduced, allowing for more general quote combinations. The output of the above script in Python 3.12 and 3.13 is

3.12.7
f'{'.' * 5}'

While this is legal Python 3.12/3.13, this representation needlessly restricts the usability of the generated code: It will not work on Python 3.11 and earlier.

I would thus like to suggest for ast.unparse to return, if possible, the more compatible code; in this case

f"{'.' * 5}"

which works across all currently supported Python versions.

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-127975: Avoid reusing quote types in ast.unparse if not needed #127980
• [3.13] gh-127975: Avoid reusing quote types in ast.unparse if not needed (GH-127980) #129600
• [3.12] gh-127975: Avoid reusing quote types in ast.unparse if not needed (GH-127980) #129601