Parse error when missing commas is inconsistent

[cfbolz]

BPO	45727
Nosy	@cfbolz, @pablogsal, @AlexWaygood
PRs	bpo-45727: Make the syntax error for missing comma more consistent #29427 [3.10] bpo-45727: Make the syntax error for missing comma more consistent (GH-29427) #29647 bpo-45727: Only trigger the 'did you forgot a comma' error suggestion if inside parentheses #29757 [3.10] bpo-45727: Only trigger the 'did you forgot a comma' error suggestion if inside parentheses. #29767

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2021-11-20.18:08:07.592>
created_at = <Date 2021-11-05.12:44:08.998>
labels = ['3.11']
title = 'Parse error when missing commas is inconsistent'
updated_at = <Date 2021-11-25.01:01:50.150>
user = 'https://github.com/cfbolz'

bugs.python.org fields:

activity = <Date 2021-11-25.01:01:50.150>
actor = 'pablogsal'
assignee = 'none'
closed = True
closed_date = <Date 2021-11-20.18:08:07.592>
closer = 'pablogsal'
components = []
creation = <Date 2021-11-05.12:44:08.998>
creator = 'Carl.Friedrich.Bolz'
dependencies = []
files = []
hgrepos = []
issue_num = 45727
keywords = ['patch']
message_count = 6.0
messages = ['405792', '405794', '406625', '406676', '406968', '406972']
nosy_count = 3.0
nosy_names = ['Carl.Friedrich.Bolz', 'pablogsal', 'AlexWaygood']
pr_nums = ['29427', '29647', '29757', '29767']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue45727'
versions = ['Python 3.11']

[cfbolz]

I found following inconsistency in the error message when there's a missing comma (it behaves that way both on main and 3.10).

Here's what happens with numbers, as expected:

Python 3.11.0a1+ (heads/main:32f55d1a5d, Nov  5 2021, 13:18:52) [GCC 11.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 1 2 3 4
  File "<stdin>", line 1
    1 2 3 4
    ^^^
SyntaxError: invalid syntax. Perhaps you forgot a comma?

But with names the error is further right in the lines:

>>> a b c d
  File "<stdin>", line 1
    a b c d
      ^^^
SyntaxError: invalid syntax. Perhaps you forgot a comma?
>>> a b c d e f g
  File "<stdin>", line 1
    a b c d e f g
              ^^^
SyntaxError: invalid syntax. Perhaps you forgot a comma?

That looks potentially quite confusing to me?

(I don't know if these nit-picky parsing issues are too annoying, if they are please tell me to stop filing them).

[pablogsal]

(I don't know if these nit-picky parsing issues are too annoying, if they are please tell me to stop filing them).

Don't worry, I think is great to discuss these cases. If there are too many, then maybe it will take a while to correct, but please, don't stop :)

That looks potentially quite confusing to me?

I agree is unfortunate that is inconsistent, but unfortunately, this is going to be a bit of a pain because the way the expression rule is reached. I will try to see if we can easily fix this without having to restructure a bunch of the grammar

[pablogsal]

New changeset 546cefc by Pablo Galindo Salgado in branch 'main':
bpo-45727: Make the syntax error for missing comma more consistent (GH-29427)
546cefc

[pablogsal]

New changeset 511ee1c by Pablo Galindo Salgado in branch '3.10':
[3.10] bpo-45727: Make the syntax error for missing comma more consistent (GH-29427) (GH-29647)
511ee1c

[pablogsal]

New changeset 24c10d2 by Pablo Galindo Salgado in branch 'main':
bpo-45727: Only trigger the 'did you forgot a comma' error suggestion if inside parentheses (GH-29757)
24c10d2

[pablogsal]

New changeset c72311d by Pablo Galindo Salgado in branch '3.10':
[3.10] bpo-45727: Only trigger the 'did you forgot a comma' error suggestion if inside parentheses. (GH-29767)
c72311d