fix(info): resolve underscore vs hyphen mismatch in schema lookup by dhruv-38 · Pull Request #16455 · rust-lang/cargo

dhruv-38 · 2026-01-01T13:16:37Z

What does this PR try to resolve?

This PR makes cargo info handle crate names with underscores (_) the same way as cargo add, by translating underscores to hyphens (-) and emitting a warning and also the other way around.

Currently, cargo info my_package and cargo info my-crate fails even when the actual crate name is my-package and my_crate respectively, which is surprising and inconsistent with other Cargo commands. This change aligns cargo info with
existing behavior and improves usability.

Fixes #16442

How to test and review this PR?

Run the added tests:
cargo test --test testsuite -- cargo_info::crate_name_normalization_from_hyphen_to_underscore
cargo test --test testsuite -- cargo_info::crate_name_normalization_from_underscore_to_hyphen

Manually verify behavior:
cargo info esp_println
cargo info big-s

This should succeed, show a warning about translating _ to - and also - to _, and display the crate info.

The change includes a test that captures the previous failing behavior and verifies the new expected output.

rustbot · 2026-01-01T13:16:42Z

r? @ehuss

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dhruv-38 · 2026-01-01T13:19:44Z

i will add one more commit for the functionality change, before that please check this code if it is good or not?

ranger-ross

I think the test looks good and does what we want. Though rustfmt is failing so you'll need to fix that.
otherwise I think you should be good to start implementing the change :)

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tests/testsuite/cargo_info/mod.rs

rustbot · 2026-01-03T06:53:23Z

This PR was rebased onto a different master 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.

ranger-ross · 2026-01-04T04:00:30Z

From discussion in #general > writing test for cargo @ 💬

One question about the selection behavior (MSRV) is: If there are 2 crates foo-bar (MSRV 1.91) and foo_bar (MSRV 1.70) and I execute cargo info foo-bar from a workspace that has an MSRV lower than 1.91 which crate should be selected. For me I feel cargo info should not change the crate name if there is an exact match, even if that exact match does not satisfy the MSRV of the current workspace.

Currently Cargo will prioritize crates that match the current workspace's MSRV (ref) when selecting the package.
This is less noticable when we have an Exact query as it only affects versions.
With normalized queries its possible for Cargo have an exact match that does not satisfy the MSRV, so we could potentially select a different crate even though the exact match exists. (which feels like the wrong behavior for cargo info to me)

Not sure how others feel about this behavior but I wanted to call this out during review.

Edit: Apparently crates.io does not allow publishing crates with the same name as an existing crate with hyphens instead of underscores and vise versa. So my concern here might not be a problem in practice. Though unsure if we need to worry about 3rd party registries. I don't see this behavior specified in the Cargo registry API docs.

src/cargo/ops/registry/info/mod.rs

ranger-ross

These changes look good to me.

Given that @0xPoe is the one that added this command originally, I'll assign them for a Cargo team member review :)

r? @0xPoe

View changes since this review

src/cargo/core/package_id_spec.rs

tests/testsuite/cargo_info/crate_name_normalization/mod.rs

src/cargo/core/package_id_spec.rs

0xPoe · 2026-01-07T21:57:44Z

I just renamed the PR title, as we usually only include one type in the Conventional Message.

src/cargo/ops/registry/info/mod.rs

tests/testsuite/cargo_info/crate_name_normalization_from_hyphen_to_underscore/mod.rs

…ith a warning

epage

Thanks @dhruv-38 for implementing this and @ranger-ross for reviewing it!

View changes since this review

Update cargo submodule 5 commits in 8c133afcd5e0d69932fe11f5907683723f8d361d..6d1bd93c47f059ec1344cb31e68a2fb284cbc6b1 2026-01-09 03:50:15 +0000 to 2026-01-10 12:53:59 +0000 - fix: preserve `dep_name` for build script metadata (rust-lang/cargo#16494) - refactor(toml): clarify `to_dependency` for config patch (rust-lang/cargo#16492) - Add `--id` flag to `cargo report timings` and `cargo report rebuilds` (rust-lang/cargo#16490) - Display lockfile path in very verbose mode when blocking (rust-lang/cargo#16491) - fix(info): resolve underscore vs hyphen mismatch in schema lookup (rust-lang/cargo#16455) --- An extra submodule update right after <#150739> due to a relatively impactful nightly regression <rust-lang/cargo#16493>

Update cargo submodule 5 commits in 8c133afcd5e0d69932fe11f5907683723f8d361d..6d1bd93c47f059ec1344cb31e68a2fb284cbc6b1 2026-01-09 03:50:15 +0000 to 2026-01-10 12:53:59 +0000 - fix: preserve `dep_name` for build script metadata (rust-lang/cargo#16494) - refactor(toml): clarify `to_dependency` for config patch (rust-lang/cargo#16492) - Add `--id` flag to `cargo report timings` and `cargo report rebuilds` (rust-lang/cargo#16490) - Display lockfile path in very verbose mode when blocking (rust-lang/cargo#16491) - fix(info): resolve underscore vs hyphen mismatch in schema lookup (rust-lang/cargo#16455) --- An extra submodule update right after <rust-lang/rust#150739> due to a relatively impactful nightly regression <rust-lang/cargo#16493>

Update cargo submodule 15 commits in 8c133afcd5e0d69932fe11f5907683723f8d361d..85eff7c80277b57f78b11e28d14154ab12fcf643 2026-01-09 03:50:15 +0000 to 2026-01-15 16:18:08 +0000 - fix(lockfile): switch to `resolver.lockfile-path` config (rust-lang/cargo#16510) - Moved build-script bins to `deps` directory (rust-lang/cargo#16515) - Invalidate the whole build cache when `-Zno-embed-metadata` changes (rust-lang/cargo#16513) - Do not create examples dir in build dir with new layout (rust-lang/cargo#16514) - fix(git): avoid partial oid got zero padded (rust-lang/cargo#16511) - Optimize cargo locate-project --workspace (rust-lang/cargo#16423) - chore: Update typos (rust-lang/cargo#16507) - refactor(git): remove unnecessary serialization (rust-lang/cargo#16505) - fix(build-std): std link metadata propagate to user (rust-lang/cargo#16496) - Improve error message for missing dependencies (rust-lang/cargo#16500) - fix: preserve `dep_name` for build script metadata (rust-lang/cargo#16494) - refactor(toml): clarify `to_dependency` for config patch (rust-lang/cargo#16492) - Add `--id` flag to `cargo report timings` and `cargo report rebuilds` (rust-lang/cargo#16490) - Display lockfile path in very verbose mode when blocking (rust-lang/cargo#16491) - fix(info): resolve underscore vs hyphen mismatch in schema lookup (rust-lang/cargo#16455) r? ghost

rustbot added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jan 1, 2026

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dhruv-38 force-pushed the cargo-info-normalize-underscore branch from b577f22 to d371702 Compare January 2, 2026 16:13

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dhruv-38 force-pushed the cargo-info-normalize-underscore branch from d371702 to e590ced Compare January 3, 2026 06:53

rustbot added A-interacts-with-crates.io Area: interaction with registries Command-info labels Jan 4, 2026

dhruv-38 changed the title ~~test(cargo-info): reproduce underscore vs hyphen lookup failure~~ test&fix(cargo-info): reproduce and fix underscore vs hyphen lookup failure Jan 4, 2026

ranger-ross reviewed Jan 4, 2026

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dhruv-38 force-pushed the cargo-info-normalize-underscore branch 2 times, most recently from ee9afc3 to 3e8367f Compare January 7, 2026 10:31

ranger-ross approved these changes Jan 7, 2026

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epage reviewed Jan 7, 2026

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0xPoe changed the title ~~test&fix(cargo-info): reproduce and fix underscore vs hyphen lookup failure~~ fix(info): resolve underscore vs hyphen mismatch in schema lookup Jan 7, 2026

epage reviewed Jan 8, 2026

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dhruv-38 added 2 commits January 8, 2026 22:22

test(cargo-info): reproduce underscore vs hyphen lookup failure

264148b

fix(cargo-info): support underscore/hyphen crate name normalization w…

dea0635

…ith a warning

dhruv-38 force-pushed the cargo-info-normalize-underscore branch from 11b9042 to dea0635 Compare January 8, 2026 22:35

epage approved these changes Jan 9, 2026

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epage added this pull request to the merge queue Jan 9, 2026

Merged via the queue into rust-lang:master with commit fe13bb8 Jan 9, 2026
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rustbot removed the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jan 9, 2026

weihanglo mentioned this pull request Jan 10, 2026

Update cargo submodule rust-lang/rust#150932

Merged

rustbot added this to the 1.94.0 milestone Jan 11, 2026

weihanglo mentioned this pull request Jan 16, 2026

Update cargo submodule rust-lang/rust#151225

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