Reset parser context in parenthesized expression #10994
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
CodSpeed Performance ReportMerging #10994 will not alter performanceComparing Summary
|
dhruvmanila
force-pushed
the
dhruv/parser
branch
from
38fb3d4
to
c30057a
Compare
dhruvmanila
force-pushed
the
dhruv/reset-ctx-in-parenthesized
branch
from
d52a6ce
to
a4fb8c0
Compare
MichaReiser
approved these changes
Apr 17, 2024
|
dhruvmanila
added a commit
that referenced
this pull request
Apr 18, 2024
## Summary This PR fixes the bug where the parser would fail to parse the following code: ```python for (x in y)[0] in z: ... ``` This is because when parsing the target of a `for` statement, the context flag for the parser is set to `FOR_TARGET` and this is used by binary expression parsing to stop the expression parsing when it sees the `in` keyword. But, in parenthesized context, this is allowed. The solution implemented in this PR is to reset the parser context when parsing a parenthesized expression and set it back to the original context later. An alternative solution would be to introduce [`ExpressionContext`](https://github.com/biomejs/biome/blob/838ccb442370e72197e625a7d0e4456e6e77e498/crates/biome_js_parser/src/syntax/expr.rs#L42-L43) but that would require a lot of updates as almost all of expression parsing function would need to be updated to take this context. A benefit of this would be that both `AllowStarredExpression` and `AllowNamedExpression` can be merged in the context and everything around `ParserCtxFlags` can be removed. It could possibly also simplify certain parsing functions. ## Test Plan Add test cases and verified the snapshots.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Summary
This PR fixes the bug where the parser would fail to parse the following code:
This is because when parsing the target of a
forstatement, the context flag for the parser is set toFOR_TARGETand this is used by binary expression parsing to stop the expression parsing when it sees theinkeyword. But, in parenthesized context, this is allowed.The solution implemented in this PR is to reset the parser context when parsing a parenthesized expression and set it back to the original context later.
An alternative solution would be to introduce
ExpressionContextbut that would require a lot of updates as almost all of expression parsing function would need to be updated to take this context. A benefit of this would be that bothAllowStarredExpressionandAllowNamedExpressioncan be merged in the context and everything aroundParserCtxFlagscan be removed. It could possibly also simplify certain parsing functions.Test Plan
Add test cases and verified the snapshots.