[@vercel/blob] Make ifMatch imply allowOverwrite, throw on contradiction#1022
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[@vercel/blob] Make ifMatch imply allowOverwrite, throw on contradiction#1022
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When ifMatch is set without allowOverwrite, the SDK now implicitly sends x-allow-overwrite: 1. When ifMatch is set with allowOverwrite: false, the SDK throws a clear error explaining the contradiction. This prevents the api-blob server from sending conflicting If-Match and If-None-Match: * headers to S3, which caused 501 NotImplemented errors surfaced as 500s to customers (INC-5751). Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
🦋 Changeset detectedLatest commit: 96e0a4d The changes in this PR will be included in the next version bump. This PR includes changesets to release 2 packages
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lucleray
approved these changes
Mar 26, 2026
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Summary
Fixes the SDK-side of INC-5751. When a customer calls
put()withifMatchbut withoutallowOverwrite: true, the server defaultsallowOverwritetofalseand sends bothIf-MatchandIf-None-Match: *to S3. S3 rejects this with 501 NotImplemented, surfaced as 500 to the customer.ifMatchis set withoutallowOverwrite, the SDK now implicitly sendsx-allow-overwrite: 1— becauseifMatch(conditional update by ETag) inherently requires overwritingifMatchis set withallowOverwrite: false, the SDK throws a clearBlobErrorexplaining the contradictionServer-side fix: vercel/api#65723
Validation
put()withifMatchand noallowOverwritesendsx-allow-overwrite: 1put()withifMatchandallowOverwrite: falsethrows descriptive errorput()withifMatchandallowOverwrite: trueworks normally🤖 Generated with Claude Code