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Why do I see a 0.0 byte file when uploading Hermes bundles?

Updated over a month ago

Issue

I'm using sentry-cli to upload source maps for a React Native project that uses the Hermes engine, and I noticed that one of the uploaded artifacts appears as a 0.0 byte file in Sentry. I'm unsure whether this is a mistake or if something went wrong during the upload process.

Applies To

  • customers uploading source maps to a React Native project using Hermes

Resolution

This is expected behavior when using sentry-cli with React Native projects that use the Hermes engine. Since Hermes bundles are not valid JavaScript and can’t be symbolicated directly, the CLI skips uploading them and instead creates a 0.0 byte placeholder file. This empty file is intentionally flagged as a minified source and linked to the correct source map, allowing Sentry to resolve stack traces properly. For more context, you can check this comment on GitHub.

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