[rustdoc] Correctly handle output options with --show-coverage by GuillaumeGomez · Pull Request #159411 · rust-lang/rust

GuillaumeGomez · 2026-07-16T21:36:36Z

The -o option was ignored with --show-coverage. This PR takes it into account and makes it closer to how these options are handled in the rest of rustdoc.

Considering calculate_doc_coverage was never really a pass and that I needed RenderOptions (for the -o option), I moved it out of passes.

r? @camelid

rustbot · 2026-07-16T21:36:41Z

camelid is currently at their maximum review capacity.
They may take a while to respond.

GuillaumeGomez · 2026-07-16T21:36:59Z

Ah, maybe @Urgau then?

r? @Urgau

Urgau · 2026-07-16T21:49:30Z

I haven't looked at the implementation, but it seems a bit weird to me to have an flag called --show-coverage that doesn't show anything when used with -o. Are we worried about confusing users?

#158929 suggests updating the documentation instead.
cc @aDotInTheVoid (in case you have an opinion)

GuillaumeGomez · 2026-07-17T08:39:07Z

I haven't looked at the implementation, but it seems a bit weird to me to have an flag called --show-coverage that doesn't show anything when used with -o. Are we worried about confusing users?

#158929 suggests updating the documentation instead. cc @aDotInTheVoid (in case you have an opinion)

If you want to generate the output in a file, that seems kinda logical to not have output on stdout.

Urgau · 2026-07-17T20:41:12Z

If you want to generate the output in a file, that seems kinda logical to not have output on stdout.

100% agree, but the CLI option is called --show-..., that implies (at least to me) -o - (i.e. the current behavior). Maybe we should have --coverage?

Is there a way to know if some users are currently relying on the current behavior? (since this is a breaking change)

GuillaumeGomez · 2026-07-17T23:10:51Z

docs.rs. We could rename the option, I don't mind. But something like --doc-coverage seems better than just coverage, no?

Urgau · 2026-07-20T16:51:42Z

Yeah, --doc-coverage seems fine. I'm mostly worried about the breaking change to --show-coverage, so if -o is respected only for this new option, that seems fine to me.

GuillaumeGomez · 2026-07-21T12:49:42Z

It's a nightly only option, so breaking changes are fine. Although in this case, as long as you don't use -o, there is no change.

Urgau · 2026-07-21T16:59:10Z

Oh! I thought --show-coverage was stable, never-mind about the breaking change then.

Though I still think renaming it to --doc-coverage would be better.

GuillaumeGomez · 2026-07-21T20:44:35Z

A follow-up and an issue about doing it would be good since we'll need an FCP. ;)

Urgau · 2026-07-21T21:12:32Z

Created #159691 for the rename.

Urgau · 2026-07-21T21:12:37Z

@bors r+

rust-bors · 2026-07-21T21:12:40Z

📌 Commit 1010137 has been approved by Urgau

It is now in the queue for this repository.

@camelid

[rustdoc] Correctly handle output options with --show-coverage Fixes rust-lang#158929. The `-o` option was ignored with `--show-coverage`. This PR takes it into account and makes it closer to how these options are handled in the rest of rustdoc. Considering `calculate_doc_coverage` was never really a pass and that I needed `RenderOptions` (for the `-o` option), I moved it out of passes. r? @camelid

@camelid

[rustdoc] Correctly handle output options with --show-coverage Fixes rust-lang#158929. The `-o` option was ignored with `--show-coverage`. This PR takes it into account and makes it closer to how these options are handled in the rest of rustdoc. Considering `calculate_doc_coverage` was never really a pass and that I needed `RenderOptions` (for the `-o` option), I moved it out of passes. r? @camelid

Rollup of 12 pull requests Successful merges: - #159582 (Sync from portable simd 2026 07 20) - #158890 (Fix splat v0 mangling) - #159411 ([rustdoc] Correctly handle output options with --show-coverage) - #159647 (Remove `early_exit` closures) - #159656 (define a `Simd` type in `minicore`) - #156474 (Add paths for linked associated items) - #159211 (Fix debuginfo argument when invoking LLBC linker) - #159527 (Bring runtime symbols statics on par with foreign functions) - #159625 (Refactor is_opsem_inhabited) - #159652 (Remove `cfg(not(no_global_oom_handling))` from the `Drop` impl of `UniqueArcUninit`) - #159657 (Remove the blanket `#![cfg_attr(test, allow(unused))]` from bootstrap ) - #159663 (Add layout cycle hang regression test)

jhpratt · 2026-07-22T00:20:24Z

@bors r- #159693 (comment)

error[E0463]: can't find crate for `std`
  |
  = note: the `thumbv6m-none-eabi` target may not support the standard library
  = note: `std` is required by `<unknown>` because it does not declare `#![no_std]`
  = help: consider building the standard library from source with `cargo build -Zbuild-std`

error: cannot resolve a prelude import

rust-bors · 2026-07-22T00:20:31Z

This pull request was unapproved.

This PR was contained in a rollup (#159693), which was unapproved.

View changes since this unapproval

aDotInTheVoid · 2026-07-23T11:02:49Z

-+-------------------------------------+------------+------------+------------+------------+
-| Total                               |          5 |      71.4% |          0 |       0.0% |
-+-------------------------------------+------------+------------+------------+------------+
+Generated output into "$TEST_BUILD_DIR/allow_missing_docs.txt"


This makes all the coverage tests not actually check that the output numbers are correct.

View changes since the review

I completely missed it. Gonna add -o - for these tests to ensure they keep the stdout check.

Ok fixed, thanks again!

aDotInTheVoid

This should update the docs to explain what the file name will be. And that stdout is the default. Right now rustdoc foo.rs --show-coverage -o foocov.txt will make foocov.txt/foo.txt, which isn't clear for the docs. (Eventually something like #149365 could help alot here).

Also, this should add a test for --emit=dep-info, for both explicit stdout and implict stdout and explicit file cases.

View changes since this review

aDotInTheVoid · 2026-07-23T11:04:20Z

            if show_coverage {
                // if we ran coverage, bail early, we don't need to also generate docs at this point
                // (also we didn't load in any of the useful passes)
                return;
            }

+            cache.crate_version = crate_version;


Why this change?

It's likely a remain when I was testing things around. Although considering we only need to set this information after the return in the if show_coverage block just above, I guess it's fine.

rustbot · 2026-07-24T09:59:21Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

…ds-target-std`

GuillaumeGomez · 2026-07-24T10:17:02Z

This should update the docs to explain what the file name will be. And that stdout is the default. Right now rustdoc foo.rs --show-coverage -o foocov.txt will make foocov.txt/foo.txt, which isn't clear for the docs. (Eventually something like #149365 could help alot here).

True, in the meantime, added the information in the book. Also to be noted, in case -o is used with --show-coverage, it displays where the file was generated.

Also, this should add a test for --emit=dep-info, for both explicit stdout and implict stdout and explicit file cases.

That seems unrelated to this PR, no?

aDotInTheVoid · 2026-07-24T17:55:19Z

That seems unrelated to this PR, no?

Previously, the coverage always went to stdout, so there was no meaningful deps-file to generate. Now that there’s a coverage output, it should depend on all the sources rustdoc read.

If that’s not solved in this PR, there should at least be an issue opened to track it.

rustbot assigned camelid Jul 16, 2026

rustbot assigned Urgau and unassigned camelid Jul 16, 2026

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GuillaumeGomez force-pushed the show-coverage branch from e124008 to f9abe70 Compare July 17, 2026 08:38

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Urgau added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jul 17, 2026

GuillaumeGomez force-pushed the show-coverage branch from f9abe70 to 1010137 Compare July 19, 2026 20:44

Urgau mentioned this pull request Jul 21, 2026

rustdoc --show-coverage is miss named #159691

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rust-bors Bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jul 21, 2026

GuillaumeGomez mentioned this pull request Jul 21, 2026

Rollup of 11 pull requests #159692

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GuillaumeGomez mentioned this pull request Jul 21, 2026

Rollup of 12 pull requests #159693

Closed

rust-bors Bot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Jul 22, 2026

aDotInTheVoid reviewed Jul 23, 2026

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GuillaumeGomez added 2 commits July 24, 2026 11:48

[rustdoc] Correctly handle output options with --show-coverage

8aafa5e

Add regression test for --show-coverage output

f545db6

GuillaumeGomez force-pushed the show-coverage branch from 7cdcfc9 to 06541f4 Compare July 24, 2026 09:59

GuillaumeGomez force-pushed the show-coverage branch from 06541f4 to 870e2b4 Compare July 24, 2026 10:00

GuillaumeGomez added 2 commits July 24, 2026 12:03

Add small message to say where the output was generated

65b6e98

Fix tests/run-make/rustdoc-show-coverage/rmake.rs by requiring `nee…

854bbe7

…ds-target-std`

GuillaumeGomez force-pushed the show-coverage branch from 870e2b4 to 854bbe7 Compare July 24, 2026 10:03

Move rustdoc-ui --show-coverage tests into the coverage folder

098056a

GuillaumeGomez force-pushed the show-coverage branch from dd6c877 to 50ce562 Compare July 24, 2026 10:16

Mention how the -o option behaves with the --show-coverage option

c680b50

GuillaumeGomez force-pushed the show-coverage branch from 50ce562 to c680b50 Compare July 24, 2026 11:56

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