[Bug]: Source maps with version 2.X and transpiler = `swc` is not working

[supercairos]

What happened?

Using ts_project doesn't produce source_maps if transpiler is defined to swc on rules 2.0

ts_project(
    name = "lib",
    srcs = glob([
        "src/**/*.ts",
    ]),
    source_map = True,
    declaration = True,
    transpiler = partial.make(
        swc,
        swcrc = ":.swcrc",
    ),
    validate = True,
    visibility = ["//visibility:public"],
    deps = [
        ":node_modules",
    ],
)

doesn't work.

Version

Development (host) and target OS/architectures:

Output of bazel --version: 6.4.0

Version of the Aspect rules, or other relevant rules from your WORKSPACE or MODULE.bazel file: rules: 2.1.0

Language(s) and/or frameworks involved: Pure TS;

How to reproduce

No response

Any other information?

No response

[supercairos]

Adding source_maps in the transpiler options fixe the issue;

   partial.make(
        swc,
        swcrc = "//hydra-api:.swcrc",
        source_maps = True,
    ),

[jbedard]

This is expected when configuring a transpiler, or even when just configuring a custom tsconfig file.

The ts_project rule needs to know what files tsc (or other transpiler such as swc) will output. When using tsconfig = {} the ts_project macro can infer some of those options, but when things like sourcemaps are configured within a tsconfig.json file or as options with in the transpiler like (like you case) the ts_project rule needs things like source_map set manually to know what files to expect as outputs.

I'll close this for now but feel free to continue the discussion here, or correct me if I'm misunderstanding something.

[supercairos]

I see your point, but I believe it's redundant. Maybe we can find a way to propagate arguments from one to an other.

Today you end-up having to set both of the source_maps:

ts_project(
    name = "lib",
    srcs = glob([
        "src/**/*.ts",
    ]),
    declaration = True,
    declaration_map = True,
    source_map = True,
    transpiler = partial.make(
        swc,
        source_maps = True,
        swcrc = ":.swcrc",
    ),
    tsconfig = "tsconfig",
    validate = True,
    deps = [
        ":node_modules",
    ],
)

and they also both have different different spellings source_map & source_maps

And we should also have an exemple with SWC in either then SWC repo or this repo to showcase this beavior

[jbedard]

It does unfortunately feel redundant, but they are separate inputs to separate tools, serving different purposes.

We do propagate ts_project(tsconfig = {"compilerOptions": {"sourceMap"}}) where the information is actually available, but when simply given tsconfig = ":target-x" or transpiler = x there is no way to determine if that tsconfig or tool has source maps enabled without this extra information that unfortunately feels redundant.

and they also both have different different spellings source_map & source_maps

The rule options are named after the options in the tools. For typescript it is the tsconfig sourceMap or cli --sourceMap while with swc it is plural. This is another case where when mixing the two (typescript and swc) it seems odd but I think this is still the best.

And we should also have an exemple with SWC in either then SWC repo or this repo to showcase this beavior

Maybe a note in the transpiler docs would be sufficient? Seems worth mentioning but I'm not sure about a full example that would run in CI etc. is necessary.

[supercairos]

Ok!

But should we make the ts_project a bit more 'agnostic' ? I feel that the API was only written for tsc and using swc seams like a workaround. For swc, It shouldn't require a tsconfig or anything more than maybe the declare = True flag ?

[jbedard]

While the transpiler can be swapped out rules_ts is still specifically for typescript so I don't think it should be agnostic. If you only want swc then you should only need rules_swc.

Note that even when the ts_project transpiler is replaced with something such as swc (or babel, or esbuild etc) tsc still does type-checking and dts generation which still requires the tsconfig.