rustdoc json output on stdout ?

[gl-yziquel]

Hi.

As of today, it seems that there is no out of the box way to get rustdoc json output on stdout. I see no way to augment the rustdoc src/lib.rs -Zunstable-options --output-format json invocation to handle output on stdout.

This is a shame as I'd like to perform rustdoc -> some jq or better for preprocessing -> tera templating -> makeinfo for texinfo generation, all of that through pipes.

As of today, the only piece of code that doesn't support piping in the above is rustdoc.

Being kind of a dinosaur, I like to get things done the old unixish way, with one tool doing something and only that, and having pipe support would allow to generate my texinfo manual from rustdoc json output without having to go jumping through hoops using temporary files.

[veera-sivarajan]

@rustbot label -needs-triage +T-rustdoc +A-rustdoc-json +C-enhancement

[chenyukang]

I also want this feature in our project.

Seems we already have the json render backend:

rust/src/librustdoc/lib.rs

Line 828 in 6292b2a

run_renderer::<json::JsonRenderer<'_>>(krate, render_opts, cache, tcx)

but currently does not enable it in command line options:

rust/src/librustdoc/lib.rs

Line 224 in 6292b2a

stable("w", |o| o.optopt("w", "output-format", "the output type to write", "[html]")),

@jyn514 do you know the the reason?

link rust-lang/rfcs#2963

[jyn514]

an rfc being accepted does not automatically stabilize the feature. the tracking issue is #76578, as linked in the rfc.

i am not sure how that's related to this issue, which is asking for json on stdout. html is stable and does not support stdout; they are independent issues.

finally, i have a "busy" indicator for a reason; i no longer work on rust. please do not ping me in random rust issues.

[aDotInTheVoid]

@chenyukang, due to Historical Reasons (TM) (#32773), rustdoc support rustdoc --output-format=html on stable, but rustdoc --output-format=json requires nightly.

See here and here for how this is implemented. You can totally use rustdoc-json on nightly today, either with cargo, or rustdoc directly.

However, both of these only support writing the output json to disk. What this issue is asking for is for is supporting outputting to stdout, instead of the filesystem.

[gl-yziquel]

@aDotInTheVoid @chenyukang Yes. This is about stdout json output. To be able to chain stuff the old unixish way using pipes and all.

[GuillaumeGomez]

I think it's a good idea. Adding it.