parsing this code results in a syntax error with an incorrect line number - it's always 1

    f'''
        { 1_a }'''

resulting in:

  File "<stdin>", line 1
    ( 1_a )
       ^
SyntaxError: invalid decimal literal

an analogue error occurs when parsing a file instead of stdin.

This bug looks like it's another instance of https://bugs.python.org/issue42209 - I commented there but there was no response for two weeks - I hope it's OK to post a new bug.

> python -VV
Python 3.10.1 (tags/v3.10.1:2cd268a, Dec  6 2021, 19:10:37) [MSC v.1929 64 bit (AMD64)]

Since #42209 was closed, a new issue seems OK.

As a result of the incorrect line number, IDLE highlights one of the opening quotes on line 1.

This also affects 3.9 I imagine, no?

> This also affects 3.9 I imagine, no?

Yes. And, from what I can tell, the same incorrect line is indicated at least all the way back to Python 3.6   (where it was "invalid token" instead of "invalid decimal literal).

Please Andre and Terry, test this fix as much as you want. I am quite sure is correct, but it is far-reaching so I want to make sure every situation that we can think of is correct (and remains correct).

I did some testing on my own using a code generator and a bunch of weird cases and I am confident this works. I am going to include this in the next alpha but will wait for your validation for some days before merging the backports.

New changeset 6fa8b2ceee38187b0ae96aee12fe4f0a5c8a2ce7 by Pablo Galindo Salgado in branch 'main':
bpo-46237: Fix the line number of tokenizer errors inside f-strings (GH-30463)
https://github.com/python/cpython/commit/6fa8b2ceee38187b0ae96aee12fe4f0a5c8a2ce7

New changeset 19a85501cee24a6e426a431243d0adcb5664c6fe by Miss Islington (bot) in branch '3.10':
bpo-46237: Fix the line number of tokenizer errors inside f-strings (GH-30463)
https://github.com/python/cpython/commit/19a85501cee24a6e426a431243d0adcb5664c6fe

Backporting this to 3.9 is a bit more challenging and more changes are required, so I am not backporting for 3.9 to avoid unintended side effects.

I understand.  I think that for IDLE, I should check that the error .text is in the line indicated, and if not, recover somehow rather than blindly marking the the indicated column.  For a shell statement entry, try to find the right line.  Not sure for an editor syntax error.  This is a rare situation in any case.