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rustdoc: Fixes with --test-run-directory and relative paths. #112751

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merged 1 commit into from
Aug 17, 2023

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@ehuss ehuss commented Jun 18, 2023

Fixes #112191
Fixes #112210

This fixes some issues with --test-run-directory and its interaction with --runtool and --persist-doctests. Relative directories don't work with Command::current_dir very well because it has platform-specific behavior with relative paths. This fixes it by avoiding the use of relative paths.

This is needed because cargo is switching to use --test-run-directory, and it uses relative paths when interacting with rustdoc/rustc.

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r? @jsha

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@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-rustdoc Relevant to the rustdoc team, which will review and decide on the PR/issue. labels Jun 18, 2023
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jsha commented Aug 17, 2023

@bors r+ rollup

Looks good, thanks! And thanks for the thorough descriptions on the linked issues. They really helped to understand what is going on.

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bors commented Aug 17, 2023

📌 Commit 31e3f56 has been approved by jsha

It is now in the queue for this repository.

@bors bors 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-review Status: Awaiting review from the assignee but also interested parties. labels Aug 17, 2023
bors added a commit to rust-lang-ci/rust that referenced this pull request Aug 17, 2023
…iaskrgr

Rollup of 5 pull requests

Successful merges:

 - rust-lang#112751 (rustdoc: Fixes with --test-run-directory and relative paths.)
 - rust-lang#114749 (Update `mpsc::Sender` doc to reflect that it implements `Sync`)
 - rust-lang#114876 (Don't ICE in `is_trivially_sized` when encountering late-bound self ty)
 - rust-lang#114881 (clarify CStr lack of layout guarnatees)
 - rust-lang#114921 (Remove Folyd from librustdoc static files)

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit da54108 into rust-lang:master Aug 17, 2023
@rustbot rustbot added this to the 1.73.0 milestone Aug 17, 2023
github-merge-queue bot pushed a commit to rust-lang/cargo that referenced this pull request May 14, 2025
This stabilizes the doctest-xcompile feature by unconditionally enabling
it.

Closes #7040
Closes #12118

## What is being stabilized?

This changes it so that cargo will run doctests when using the
`--target` flag for a target that is not the host. Previously, cargo
would ignore doctests (and show a note if passing `--verbose`).

A wrapper for running the doctest can be specified with the
[`target.*.runner`](https://doc.rust-lang.org/cargo/reference/config.html#targettriplerunner)
configuration option (which is powered by the `--test-runtool` rustdoc
flag). This would typically be something like qemu to run under
emulation. It is my understanding that this should work just like
running other kinds of tests.

Additionally, the
[`target.*.linker`](https://doc.rust-lang.org/cargo/reference/config.html#targettriplelinker)
config option is honored for using a custom linker.

Already stabilized in rustdoc is the ability to [ignore tests
per-target](https://doc.rust-lang.org/nightly/rustdoc/write-documentation/documentation-tests.html#ignoring-targets).

## Motivation

The lack of doctest cross-compile support has always been simply due to
the lack of functionality in rustdoc to support this. Rustdoc gained the
ability to cross-compile doctests some time ago, but there were
additional flags like the test runner that were not stabilized until
just recently.

This is intended to ensure that projects have full test coverage even
when doing cross-compilation. It can be
[surprising](#12118) to some
that this was not happening, particularly since cargo is silent about
it.

## Risks

The cargo team had several conversations about how to roll out this
feature. Ultimately we decided to enable it unconditionally with the
understanding that most projects will probably want to have their
doctests covered, and that any breakage will be a local concern that can
be resolved by either fixing the test or ignoring the target.

Tests in rust-lang/rust run into this issue, [particularly on
android](rust-lang/rust#119147 (comment)),
and those will need to be fixed before this reaches beta. This is
something I am looking into.

Some cross-compiling scenarios may need codegen flags that are not
supported. It's not clear how common this will be, or if ignoring will
be a solution, or how difficult it would be to update rustdoc and cargo
to support these. Additionally, the split between RUSTFLAGS and
RUSTDOCFLAGS can be cumbersome.

## Implementation history

- rust-lang/rust#60387 -- Support added to
rustdoc to support the `--target` flag and runtool and
per-target-ignores.
- #6892 -- Initial support in
cargo.
- #7391 -- Added unstable
documentation.
- #8094 -- Fix target for doc
test cross compilation
- #8358 -- Fixed regression with
`--target=HOST` not working on stable.
- #10132 -- Added note about
doctests not running (under `--verbose`).
- rust-lang/rust#112751 -- Fixed
`--test-run-directory` interaction with `--test-runtool`.
- rust-lang/rust#137096 -- Stabilization (and
rename) of the rustdoc `--test-runtool` and `--test-runtool-arg` CLI
args, and drops `--enable-per-target-ignores` unconditionally enabling
it.

## Test coverage

Cargo tests:
-
[artifact_dep::cross_doctests_works_with_artifacts](https://github.com/ehuss/cargo/blob/56c08f84e28d3653ae0c842f331a226738108188/tests/testsuite/artifact_dep.rs#L1248-L1326)
-- Checks that doctest has access to the artifact dependencies.
-
[build_script::duplicate_script_with_extra_env](https://github.com/ehuss/cargo/blob/56c08f84e28d3653ae0c842f331a226738108188/tests/testsuite/build_script.rs#L5514-L5614)
-- Checks that build-script env and cfg values are correctly handled on
host versus target when cross running doctests.
-
[cross_compile::cross_tests](https://github.com/ehuss/cargo/blob/56c08f84e28d3653ae0c842f331a226738108188/tests/testsuite/cross_compile.rs#L416-L502)
-- Basic test that cross-compiled tests work.
-
[cross_compile::doctest_xcompile_linker](https://github.com/ehuss/cargo/blob/56c08f84e28d3653ae0c842f331a226738108188/tests/testsuite/cross_compile.rs#L1139-L1182)
-- Checks that the linker config argument works.
-
[custom_target::custom_target_minimal](https://github.com/ehuss/cargo/blob/56c08f84e28d3653ae0c842f331a226738108188/tests/testsuite/custom_target.rs#L39-L71)
-- Checks that `.json` targets work with rustdoc cross tests.
-
[test::cargo_test_doctest_xcompile_ignores](https://github.com/ehuss/cargo/blob/56c08f84e28d3653ae0c842f331a226738108188/tests/testsuite/test.rs#L4743-L4777)
-- Checks the `ignore-*` syntax works.
-
[test::cargo_test_doctest_xcompile_runner](https://github.com/ehuss/cargo/blob/2603268cda3e32565ac27ee642f2b755fa590bac/tests/testsuite/test.rs#L4783-L4863)
-- Checks runner with cross doctests.
-
[test::cargo_test_doctest_xcompile_no_runner](https://github.com/ehuss/cargo/blob/2603268cda3e32565ac27ee642f2b755fa590bac/tests/testsuite/test.rs#L4869-L4907)
-- Checks cross doctests without a runner.

Rustdoc tests:
-
[run-make/doctest-runtool](https://github.com/rust-lang/rust/tree/25cdf1f67463c9365d8d83778c933ec7480e940b/tests/run-make/doctests-runtool)
-- Tests behavior of `--test-run-directory` with relative paths of the
runner.
-
[rustdoc/doctest/doctest-runtool](https://github.com/rust-lang/rust/blob/25cdf1f67463c9365d8d83778c933ec7480e940b/tests/rustdoc/doctest/doctest-runtool.rs)
-- Tests for `--test-runtool` and `--test-runtool-arg`.

## Future concerns

There have been some discussions
(rust-lang/testing-devex-team#5) about
changing how doctests are driven. My understanding is that stabilizing
this should not affect those plans, since if cargo becomes the driver,
it will simply need to build things with `--target` and use the
appropriate runner.

## Change notes

This PR changed tests a little:
- artifact_dep::no_cross_doctests_works_with_artifacts was changed now
that doctests actually work.
- cross_compile::cross_tests was changed to properly check doctests.
- cross_compile::no_cross_doctests dropped since it is no longer
relevant.
- standard_lib::doctest didn't need `-Zdoctest-xcompile` since
`-Zbuild-std` no longer uses a target.
- test::cargo_test_doctest_xcompile was removed since it is a duplicate
of cross_compile::cross_tests

I think this should probably wait until the next release cutoff, moving
this to 1.89 (will update the PR accordingly if that happens).
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