Add syntax error when conversion flag does not immediately follow exclamation mark (#18706)

Closes #18671

Note that while this has, I believe, always been invalid syntax, it was
reported as a different syntax error until Python 3.12:

Python 3.11:

```pycon
>>> x = 1
>>> f"{x! s}"
  File "<stdin>", line 1
    f"{x! s}"
             ^
SyntaxError: f-string: invalid conversion character: expected 's', 'r', or 'a'
```

Python 3.12:

```pycon
>>> x = 1
>>> f"{x! s}"
  File "<stdin>", line 1
    f"{x! s}"
        ^^^
SyntaxError: f-string: conversion type must come right after the exclamanation mark
```
This commit is contained in:
Dylan 2025-06-16 11:44:42 -05:00 committed by GitHub
parent a842899862
commit c5b58187da
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8 changed files with 219 additions and 38 deletions

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@ -267,17 +267,13 @@ aaaaaaaaaaa = f"""asaaaaaaaaaaaaaaaa {
# Conversion flags
#
# This is not a valid Python code because of the additional whitespace between the `!`
# and conversion type. But, our parser isn't strict about this. This should probably be
# removed once we have a strict parser.
x = f"aaaaaaaaa { x ! r }"
# Even in the case of debug expressions, we only need to preserve the whitespace within
# the expression part of the replacement field.
x = f"aaaaaaaaa { x = ! r }"
x = f"aaaaaaaaa { x = !r }"
# Combine conversion flags with format specifiers
x = f"{x = ! s
x = f"{x = !s
:>0
}"

View file

@ -265,17 +265,13 @@ aaaaaaaaaaa = t"""asaaaaaaaaaaaaaaaa {
# Conversion flags
#
# This is not a valid Python code because of the additional whitespace between the `!`
# and conversion type. But, our parser isn't strict about this. This should probably be
# removed once we have a strict parser.
x = t"aaaaaaaaa { x ! r }"
# Even in the case of debug expressions, we only need to preserve the whitespace within
# the expression part of the replacement field.
x = t"aaaaaaaaa { x = ! r }"
x = t"aaaaaaaaa { x = !r }"
# Combine conversion flags with format specifiers
x = t"{x = ! s
x = t"{x = !s
:>0
}"