"pub serve" should provide the ability to look up mappings between source and output lines

[nex3]

It should be possible (via the "pub serve" websocket API) to provide the server with a source file and line number and get the corresponding output URL and line number, and vice versa.

This particular bug is intended to track the bare minimum feature set necessary to provide parity with the editor's current server. Specifically, it only needs to support Dart inputs and outputs with no transformers in between. Issue #12339 is tracking the broader use of this with all transformers.

[nex3]

Marked this as blocking #15830.

[munificent]

Removed Priority-Unassigned label.
Added Priority-Medium label.

[munificent]

Set owner to @munificent.
Removed Type-Defect label.
Added Type-Enhancement, Started labels.

[munificent]

Hey, Keerti and/or Devon!

Can you sketch out what kind of Web Socket API you'd like to see for this?

Do you want a mapping from source file to served URL, or vice versa? Both? Do you need column information or just lines?

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cc @keertip.
cc @devoncarew.

[munificent]

Added NeedsInfo label.

[munificent]

Talked about it with Keerti this morning. My understanding is that the Editor needs mapping in both directions:

1. Given a package name, a relative path to a source file on disc within that package, and a line number, return the URL to the corresponding output for that file as is served by pub serve along with the matching line number in the output file.
2. Given a URL for an output asset and a line number, return the package name, relative path and line number for the source file that corresponds to that asset.

Ex. package "foo", path: "some/path.dart" <-> "/packages/foo/some/path.dart"

We're OK with only supporting .dart files that are not transformed (or at least not transformed in a way that affects line numbering) for a first-pass implementation of this.

Keerti, does that sound right? Do you need column information too, or just lines?

[munificent]

Added Started label.

[munificent]

Added Fixed label.

[DartBot]

This issue has been moved to dart-lang/pub#813.