fix(filesystem): handle Windows EPERM when renaming over locked files#3296
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MattBenesch wants to merge 1 commit intomodelcontextprotocol:mainfrom
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fix(filesystem): handle Windows EPERM when renaming over locked files#3296MattBenesch wants to merge 1 commit intomodelcontextprotocol:mainfrom
MattBenesch wants to merge 1 commit intomodelcontextprotocol:mainfrom
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On Windows, fs.rename() fails with EPERM when the target file is locked by another process (e.g., open in an editor). This adds a fallback that uses fs.cp() + fs.unlink() when EPERM is encountered, allowing edits to succeed even when the file is open. Fixes modelcontextprotocol#3199
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On Windows, fs.rename() fails with EPERM when the target file is locked by another process (e.g., open in an editor). This adds a fallback that uses fs.cp() + fs.unlink() when EPERM is encountered, allowing edits to succeed even when the file is open.
Fixes #3199
Description
Adds atomicReplaceFile() helper that falls back to fs.cp() when fs.rename() fails with EPERM.
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Server Details
Motivation and Context
On Windows, files open in editors (VS Code, Notepad, etc.) are locked. The current fs.rename() approach fails with EPERM when trying to atomically replace these locked files. This prevents users from editing files they have open.
How Has This Been Tested?
Unit tests added for EPERM fallback behavior. All 46 lib.test.ts tests pass.
Breaking Changes
None - existing behavior unchanged on Linux/macOS. Windows users will now have edits succeed where they previously failed.
Types of changes
Checklist
Additional context