[rustdoc] Integration test documentation build failure

[bwidawsk]

Problem

When trying to build documentation for integration tests, the primary crate is not included and therefore cannot be found. This is useful for documenting common APIs in integration tests as documented

> cargo rustdoc --lib --test doctest
 Documenting rustdoc-test-repro v0.1.0 (/home/bwidawsk/dev/rustdoc-test-repro)
error[E0432]: unresolved import `rustdoc_test_repro`
 --> tests/main.rs:2:5
  |
2 | use rustdoc_test_repro;
  |     ^^^^^^^^^^^^^^^^^^ no external crate `rustdoc_test_repro`

For more information about this error, try `rustc --explain E0432`.
error: could not document `rustdoc-test-repro`

Caused by:
  process didn't exit successfully: `/home/bwidawsk/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustdoc --edition=2021 --crate-type bin --crate-name doctest tests/main.rs -o /home/bwidawsk/dev/rustdoc-test-repro/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=167 -C metadata=82b36fa1636c8440 -L dependency=/home/bwidawsk/dev/rustdoc-test-repro/target/debug/deps --crate-version 0.1.0` (exit status: 1)

Steps

1. Add documentation to an integration test
2. build documentation something like: cargo rustdoc --lib --test doctest

A simple reproducer is here. Simple run failure.sh

Possible Solution(s)

No response

Notes

No response

Version

cargo 1.75.0 (1d8b05cdd 2023-11-20)
release: 1.75.0
commit-hash: 1d8b05cdd1287c64467306cf3ca2c8ac60c11eb0
commit-date: 2023-11-20
host: x86_64-unknown-linux-gnu
libgit2: 1.7.1 (sys:0.18.1 vendored)
libcurl: 8.4.0-DEV (sys:0.4.68+curl-8.4.0 vendored ssl:OpenSSL/1.1.1u)
ssl: OpenSSL 1.1.1u  30 May 2023
os: Arch Linux Rolling Release [64-bit]

[epage]

cargo rustdoc --lib --test doctest

I'm curious, why are you documenting tests?

[bwidawsk]

cargo rustdoc --lib --test doctest

I'm curious, why are you documenting tests?

I want to document the common API for tests so other people can write their own tests.
I'm using libtest-mimic (and maybe nexttest) to facilitate writing and running a conformance test suite.

[weihanglo]

Although the original issue on Zulip seems to be resolved, this looks like a feature that cargo rustdoc never supports. I wonder if those flags should be hidden or removed, making the command have the more or less the same as cargo doc.

[ehuss]

The Cargo team briefly discussed this, and felt like it would be best to remove the flags that aren't working (to make it in sync with cargo doc) for now, and then possibly revisit supporting the flags in the future.