Expose source map path/dir to `rewriteSources` hook

[ktarmyshov]

Problem Statement

Dear Sentry Team,

I am integrating @sentry/sveltekit with a custom SvelteKit adapter for Azure Static Web Apps.

I was able to make the sourcemap flow work, but I ran into a limitation in the rewriteSources hook API.

Context:

• My adapter is not one of the built-in adapter targets, so I use:
  sentrySvelteKit({ adapter: 'other', ... })
• To keep sourcemaps correct in the final adapter output, I re-bundle / re-emit .svelte-kit/output/server and .svelte-kit/output/client into the adapter output directories instead of raw-copying them.
• My demo/test app lives in ./tests/demo, so source paths need additional rewriting in a monorepo-style layout.
• I currently solve this with:
  unstable_sentryVitePluginOptions.sourcemaps.rewriteSources

The problem:
today the hook only receives (source, map), but in my case I also need to know where the current source map file is located.

Something like this would be very helpful:

type RewriteSourcesHook = (source: string, map: any, mapPath: string) => string;

or at least:

type RewriteSourcesHook = (source: string, map: any, mapDir: string) => string;

Why this would help:
in order to rewrite relative source paths correctly, I need to resolve them relative to the source map location, not just relative to process.cwd().

Conceptually I need to do something like:

resolve(mapDir, source)

At the moment, because the hook does not provide the map location, I have to:

1. scan directories,
2. read .map files,
3. find which map contains the given source entry,
4. reconstruct the directory of that map,
5. only then rewrite the source path.

So most of my implementation is just working around the missing mapDir / mapPath context.

Providing either mapDir or mapPath to the hook would remove most of that complexity and make rewriteSources much easier to use for custom adapters and monorepo-like layouts.

My current implementation is here for reference:
https://github.com/kt-npm-modules/svelte-adapter-azure-swa/blob/main/src/utils.js

Would you consider exposing the source map directory or path to rewriteSources?

Thank you!
Konstantin

Solution Brainstorm

https://github.com/kt-npm-modules/svelte-adapter-azure-swa/blob/main/src/utils.js
https://github.com/kt-npm-modules/svelte-adapter-azure-swa/blob/2d0da5a00063f5d2758837a3b7648671bd11e33b/tests/demo/vite.config.ts#L28

Additional Context

No response

Priority

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[linear-code]

JS-2018