fix: preserve legal comments in bundler to match esbuild behavior #21870
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Bun.build now preserves legal comments like esbuild does: - Comments starting with /*! or //! (already supported) - Comments containing @license, @preserve, or @copyright (new) This fixes GitHub issue #9795 by making Bun's bundler behavior consistent with esbuild's legal comment preservation. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <[email protected]>
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Adds the --legal-comments CLI option with values: - none: Disable legal comment preservation - inline: Keep legal comments inline in code (default for non-bundling) - eof: Move legal comments to end of file (default for bundling) - linked: Extract to separate .LEGAL.txt file with link - external: Extract to separate .LEGAL.txt file without link This provides full esbuild CLI compatibility for legal comment handling. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <[email protected]>
Adds full JavaScript API support for the legalComments option:
- Bun.build({ legalComments: "none" | "inline" | "eof" | "linked" | "external" })
- Proper enum validation with helpful error messages for invalid values
- Integration with bundler configuration pipeline
- Comprehensive test coverage in bun-build-api.test.ts
Example usage:
```javascript
await Bun.build({
entrypoints: ["src/index.js"],
legalComments: "eof", // Move legal comments to end of file
outdir: "dist"
});
```
This completes the esbuild compatibility for legal comment handling
in both CLI and JavaScript API.
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <[email protected]>
pfgithub
suggested changes
Aug 14, 2025
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expected_version needs to be updated in RuntimeTranspilerCache.zig
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Summary
@license,@preserve, or@copyright(in addition to existing/*!and//!support)--legal-commentsCLI option for full esbuild compatibilitylegalCommentsoption toBun.build()JavaScript APIFeatures
Legal Comment Preservation
Before this change:
After this change:
Legal comment patterns now preserved:
/*!style comments (already supported)//!style comments (already supported)@license(new)@preserve(new)@copyright(new)CLI Option Support
NEW:
--legal-commentsoption with esbuild-compatible values:--legal-comments=none- Disable legal comment preservation--legal-comments=inline- Keep legal comments inline in code--legal-comments=eof- Move legal comments to end of file (default)--legal-comments=linked- Extract to separate.LEGAL.txtfile with link--legal-comments=external- Extract to separate.LEGAL.txtfile without linkExample CLI usage:
JavaScript API Support
NEW:
legalCommentsoption inBun.build():Features:
Test plan
bun-build-api.test.tsComplete esbuild compatibility: Both CLI and JavaScript API now fully match esbuild's legal comment handling behavior.
Closes #9795
🤖 Generated with Claude Code