fix(linter): prevent useConsistentCurlyBraces from suggesting invalid JSX text conversion #8439

tt-a1i · 2025-12-13T14:47:09Z

Summary

This PR fixes #8011 where useConsistentCurlyBraces would suggest removing curly braces from JSX expression children containing characters that would cause parsing issues or semantic changes when converted to plain JSX text.

Changes

Added forbidden characters check to FORBIDDEN_CHARS in use_consistent_curly_braces.rs with detailed doc comments explaining the rationale.

Characters that cause issues when converted from JSX expression to plain JSX text:

{ } - would be parsed as expression delimiters
< > - would be parsed as tag delimiters
& - would be parsed as HTML entity start
" ' - included for consistency

Scope: This guard applies only to JSX children (not attributes), because attribute strings have different parsing rules where these characters are safe.

Before this fix:

// Input
<Foo>{"start {{"}</Foo>
<Foo>{"<script>"}</Foo>
<Foo>{"Tom & Jerry"}</Foo>

// After unsafe fix (invalid/different JSX!)
<Foo>start {{</Foo>      // syntax error - { starts expression
<Foo><script></Foo>      // becomes an actual script tag!
<Foo>Tom & Jerry</Foo>   // & might be interpreted as entity start

After this fix, the rule correctly leaves these strings alone.

Test Plan

Added test cases for {, <, & in valid.jsx
Ran cargo test -p biome_js_analyze use_consistent_curly_braces - all tests pass

AI Assistance Disclosure

This PR was written with assistance from Claude Code.

changeset-bot · 2025-12-13T14:47:14Z

🦋 Changeset detected

Latest commit: e943457

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 13 packages

Name	Type
@biomejs/biome	Patch
@biomejs/cli-win32-x64	Patch
@biomejs/cli-win32-arm64	Patch
@biomejs/cli-darwin-x64	Patch
@biomejs/cli-darwin-arm64	Patch
@biomejs/cli-linux-x64	Patch
@biomejs/cli-linux-arm64	Patch
@biomejs/cli-linux-x64-musl	Patch
@biomejs/cli-linux-arm64-musl	Patch
@biomejs/wasm-web	Patch
@biomejs/wasm-bundler	Patch
@biomejs/wasm-nodejs	Patch
@biomejs/backend-jsonrpc	Patch

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coderabbitai · 2025-12-13T14:50:05Z

Walkthrough

The PR updates the useConsistentCurlyBraces lint to avoid suggesting removal of JSX curly braces when the contained string literal includes characters that cannot appear unescaped in JSX text (forbidden characters: {, }, <, >, &, " and '). It adds a changeset entry for a patch release and new tests covering edge cases that previously produced invalid or semantically altered JSX, addressing issue #8011.

Possibly related PRs

fix(lint/useConsistentCurlyBraces): adjust condition to allow removing the braces #7497: Modifies the same use_consistent_curly_braces logic and related tests (forbidden-character and whitespace checks) that affect removal of JSX curly braces.

Suggested reviewers

ematipico
siketyan

Pre-merge checks and finishing touches

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description check	✅ Passed	Description clearly explains the issue, the fix (forbidden characters check), examples of problematic transformations, and test coverage.
Linked Issues check	✅ Passed	PR fully addresses issue #8011 by expanding FORBIDDEN_CHARS and updating the rule logic to prevent unsafe JSX transformations for strings containing {, }, <, >, &, ", and '.
Out of Scope Changes check	✅ Passed	All changes are directly related to fixing issue #8011: the changeset entry, the rule implementation, and test cases for the forbidden character fix.
Title check	✅ Passed	The title accurately describes the main fix: preventing useConsistentCurlyBraces from suggesting invalid JSX text conversions when encountering forbidden characters.

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Actionable comments posted: 0

🧹 Nitpick comments (1)

.changeset/fix-curly-braces-opening-brace.md (1)
1-5: Add a code example to the changeset.

As per coding guidelines, changesets for rule changes should include code examples. Consider adding a brief before/after snippet, e.g.:
Before: `<Foo>{'start {{'}</Foo>` → invalid `<Foo>start {{</Foo>`  
After: braces are preserved when strings contain `{`
Based on coding guidelines, changesets should include code examples for rules.

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📥 Commits

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⛔ Files ignored due to path filters (1)

crates/biome_js_analyze/tests/specs/style/useConsistentCurlyBraces/valid.jsx.snap is excluded by !**/*.snap and included by **

📒 Files selected for processing (3)

.changeset/fix-curly-braces-opening-brace.md (1 hunks)
crates/biome_js_analyze/src/lint/style/use_consistent_curly_braces.rs (1 hunks)
crates/biome_js_analyze/tests/specs/style/useConsistentCurlyBraces/valid.jsx (1 hunks)

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📓 Path-based instructions (2)

.changeset/*.md

📄 CodeRabbit inference engine (CONTRIBUTING.md)

Write changesets that are concise (1-3 sentences), user-focused, use past tense for actions taken and present tense for Biome behavior, include code examples for rules, and end sentences with periods

Files:

.changeset/fix-curly-braces-opening-brace.md

crates/**/*.rs

📄 CodeRabbit inference engine (CONTRIBUTING.md)

Update inline rustdoc documentation for rules, assists, and their options when adding new features or changing existing features in Rust crates

Files:

crates/biome_js_analyze/src/lint/style/use_consistent_curly_braces.rs

🧠 Learnings (14)

📓 Common learnings

Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-27T23:04:02.022Z
Learning: Applies to crates/biome_analyze/**/*analyze/src/lint/**/*.rs : Use language tags in documentation code blocks (js, ts, tsx, json, css) and order properties consistently as: language, then `expect_diagnostic`, then options modifiers, then `ignore`, then `file=path`

Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-27T23:04:02.022Z
Learning: Applies to crates/biome_analyze/**/*analyze/src/lint/**/*.rs : Use the `noUnsafe` prefix for rules that report code leading to runtime failures (e.g., `noUnsafeOptionalChaining`)

Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-27T23:04:02.022Z
Learning: Applies to crates/biome_analyze/**/*analyze/src/lint/**/*.rs : Code actions must specify a `fix_kind` field in the `declare_lint_rule!` macro as either `FixKind::Safe` or `FixKind::Unsafe` to indicate whether fixes always preserve program behavior

Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-27T23:04:02.022Z
Learning: Applies to crates/biome_analyze/**/*analyze/src/lint/**/*.rs : Use the `noInvalid` prefix for rules that report runtime errors from mistyping (e.g., `noInvalidConstructorSuper`)