# Sentry: minified stack traces, source maps not applying
## The symptom
Issues show minified frames (`a.b.c`) with no source context, even though you upload source maps.
## How linking works now
Sentry injects Debug IDs into your build output and matches uploaded artifacts by those IDs. The old filename-matching heuristics are the fallback, not the mechanism. If the deployed bundle has no Debug IDs, uploads cannot attach to anything.
## The doc's own troubleshooting strings
- **"Sentry not part of build pipeline"**: your deployed code is missing Debug IDs. Run `npx @sentry/wizard@latest -i sourcemaps` and make sure you are shipping a production build. Dev builds typically do not generate maps for upload.
- **"Source maps not applying"**: verify artifacts are uploaded before errors occur. Uploads that land after the error are useless for that error.
## The ordering rule
Upload must happen in the build, before deploy, and the release/dist of the upload must match the release/dist of the running code. Common breaks:
1. Upload runs in CI but the deploy ships a different build (rebuilt Docker layer, different commit).
2. `SENTRY_ALLOW_FAILURE` was set so a failed upload did not block CI, and nobody noticed uploads failing for weeks.
3. Auth token fixed but the upload step still points at the wrong org/project.
## Confirmation and fix
Open an issue, check a frame, and look for the debug ID. Then check Project Settings > Source Maps (or Debug Files) for an artifact with that ID. Missing ID on the event means the build did not inject; missing artifact means the upload did not land. Fix the build step, redeploy, and confirm the next error resolves to real source lines.