[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Pablo Galindo Salgado added the comment: New changeset a8c418d5ed1103106db547aa576b82c6031985a4 by Pablo Galindo in branch '3.10': [3.10] bpo-44368: Improve syntax errors with invalid as pattern targets (GH-26632) (GH-26792) https://github.com/python/cpython/commit/a8c418d5ed1103106db547aa57

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Change by Pablo Galindo Salgado : -- pull_requests: +25376 pull_request: https://github.com/python/cpython/pull/26792 ___ Python tracker ___ ___

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Pablo Galindo Salgado added the comment: New changeset 05073036dcecefc00b0c3e7397601809da41e2f1 by Pablo Galindo in branch 'main': bpo-44368: Improve syntax errors with invalid as pattern targets (GH-26632) https://github.com/python/cpython/commit/05073036dcecefc00b0c3e7397601809da41e2f1 --

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Pablo Galindo Salgado added the comment: Checkout PR 26632, and see if this works for you -- ___ Python tracker ___ ___ Python-bugs

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Change by Pablo Galindo Salgado : -- pull_requests: +25218 pull_request: https://github.com/python/cpython/pull/26632 ___ Python tracker ___ ___

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Pablo Galindo Salgado added the comment: > Could we just try parsing "as _" and raise if so? That wouldn't conflict with > any existing rules, and that way we could actually have a helpful error > message. No, the same happens with other targets such as: File "/home/pablogsal/github/python

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

miss-islington added the comment: New changeset f807a4fad4da8f629ea7fe1f00719e817c77b63c by Miss Islington (bot) in branch '3.10': bpo-44368: Ensure we don't raise incorrect custom syntax errors with soft keywords (GH-26630) https://github.com/python/cpython/commit/f807a4fad4da8f629ea7fe1f00

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Brandt Bucher added the comment: Like "SyntaxError: can't capture into a wildcard (consider removing)". -- ___ Python tracker ___ _

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Brandt Bucher added the comment: Could we just try parsing "as _" and raise if so? That wouldn't conflict with any existing rules, and that way we could actually have a helpful error message. -- ___ Python tracker

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Pablo Galindo Salgado added the comment: Oh, this one is actually correct: match ...: case 42 as _: pass File "", line 2 case 42 as _: ^ SyntaxError: expected ':' That is literally expecting a ":" and that's the error. It has identified "case 42" correctly a

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Pablo Galindo Salgado added the comment: New changeset 457ce60fc70f1c9290023f46fb82b6a490dff32e by Pablo Galindo in branch 'main': bpo-44368: Ensure we don't raise incorrect custom syntax errors with soft keywords (GH-26630) https://github.com/python/cpython/commit/457ce60fc70f1c9290023f46fb

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Change by miss-islington : -- nosy: +miss-islington nosy_count: 3.0 -> 4.0 pull_requests: +25217 pull_request: https://github.com/python/cpython/pull/26631 ___ Python tracker _

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Pablo Galindo Salgado added the comment: I will fix that one in another PR -- ___ Python tracker ___ ___ Python-bugs-list mailing l

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Pablo Galindo Salgado added the comment: > Is this covered by your fix? No, that is not a backtracking error (is not going all the way to the "match" expression). -- ___ Python tracker

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Brandt Bucher added the comment: I found a similar one, by the way (not related to mapping patterns): match ...: case 42 as _: pass File "", line 2 case 42 as _: ^ SyntaxError: expected ':' Is this covered by your fix? -- ___

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Brandt Bucher added the comment: Wow, that was quite a roller-coaster ride. Thanks Pablo. :) -- ___ Python tracker ___ ___ Python-b

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Change by Pablo Galindo Salgado : -- keywords: +patch pull_requests: +25216 stage: -> patch review pull_request: https://github.com/python/cpython/pull/26630 ___ Python tracker __

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Pablo Galindo Salgado added the comment: Oh, turns out I already added machinery to solved this but I was missing a piece! -- ___ Python tracker ___ _

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Pablo Galindo Salgado added the comment: I think it actually will be very useful to explain that these cases are invalid in the Syntax error, which will also solve this problem. This on the other hand shows a bigger problem: any generic syntax error that happens inside "match" will probably

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Pablo Galindo Salgado added the comment: Oh, wait, I think I misunderstood the problem. The problem is that the parser is backtracking and identifying match as a name. Indeed, the soft keyword is a pain :( -- ___ Python tracker

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Pablo Galindo Salgado added the comment: The backtracking with the soft keyword may make this very annoying, by the way. -- ___ Python tracker ___

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Pablo Galindo Salgado added the comment: Probably, otherwise is going to hurt because the syntax errors that you describe trigger when two names are place together, which in general is a missing comma. The error message also doesn't say: "you are missing a comma" it says that the most typic

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

Brandt Bucher added the comment: Perhaps we need something like invalid_mapping_pattern or invalid_mapping_pattern_double_star rules? -- ___ Python tracker ___ __

[issue44368] Invalid mapping patterns give confusing SyntaxErrors

New submission from Brandt Bucher : Here are a few that I found. Not sure when they were introduced: match ...: case {**rest, "key": value}: pass match ...: case {"first": first, **rest, "last": last}: pass match ...: case {**_}: pass These all give the fo