Source Map: Original file name not returned; bundle name returned.

[stahlbauer]

When querying the source map via span_to_filename (from within my plugins` code), the bundle name is returned instead of the original file name. Is this a known issue? What might I do wrong?

[kwonoj]

Mind elaborate what bundle name exactly mean? Plugin's span_to_filename is proxy to the host's same call, so it depends to what filename host gets when it is transformed.

[stahlbauer]

Certainly: I am using SWC to process files that have been produced by bundlers like Webpack, RollUp, and so on. That is, these input files have already been produced from other files (for example, from TypeScript code) and have a source map included. I would like to be able to map back to the very original files the code was stemming from based on the source map information and use that information to control how my SWC plugin behaves.

[kwonoj]

Afaik it's expected behavior currently. It sounds like similar to the #1388, which doesn't consume the sourcemap for the source of the transform - swc's cli have explicit extend to inherit input sourcemap, but unsure if it's applied to the swc/core.

[stahlbauer]

Good reminder ;) Thanks. Some time passed by since touching that.