[bazel] Swap to rules_rs for Rust build rules by dzbarsky · Pull Request #17398 · SeleniumHQ/selenium

dzbarsky · 2026-04-27T01:03:54Z

💥 What does this PR do?

This PR migrates to using rules_rs instead of rules_rust for our Cargo lockfile integration and toolchains. rules_rs is a redesign ruleset that can operate directly on Cargo.toml/Cargo.lock without the need for additional bazel lockfiles or a bazel-specific repin operation. The toolchains are also optimized to minimize downloads of duplicative bytes compared to the default rules_rust ones.

🔧 Implementation Notes

This was straightforward.

🤖 AI assistance

Codex 0-shot :) It followed the instructions in rules_rs README perfectly.

💡 Additional Considerations

N/a

🔄 Types of changes

Cleanup / build ergonomics improvement

CLAassistant · 2026-04-27T01:04:04Z

All committers have signed the CLA.

qodo-code-review · 2026-04-27T01:04:07Z

Review Summary by Qodo

Migrate Rust build rules from rules_rust to rules_rs

✨ Enhancement

Walkthroughs

Description

• Migrate Rust build system from rules_rust to rules_rs
• Simplify Cargo dependency management without bazel lockfiles
• Remove manual cargo repinning task and workflow
• Add platform-specific constraints for Linux and Windows
• Update Bazel module dependencies and toolchain configuration

File Changes

1. MODULE.bazel ⚙️ Configuration changes +44/-10

Update Bazel dependencies and Rust toolchain configuration

MODULE.bazel

2. BUILD.bazel ⚙️ Configuration changes +16/-0

Add platform definitions for Linux and Windows

BUILD.bazel

3. .bazelrc ⚙️ Configuration changes +3/-1

Update build configuration for platform-specific settings

.bazelrc

View more (6)

4. rust/private/rustfmt_wrapper.bzl Dependencies +4/-8

Update Rust rule imports to use rules_rs

rust/private/rustfmt_wrapper.bzl

5. rust/BUILD.bazel ✨ Enhancement +4/-1

Add aliases support for Rust binary and library targets

rust/BUILD.bazel

6. rust/tests/BUILD.bazel ✨ Enhancement +2/-1

Add aliases support for Rust test suite

rust/tests/BUILD.bazel

7. rake_tasks/rust.rake Cleanup +0/-16

Remove manual cargo repinning task

rake_tasks/rust.rake

8. README.md 📝 Documentation +1/-5

Simplify Rust dependency documentation

README.md

9. rust/AGENTS.md 📝 Documentation +0/-1

Remove cargo repinning command from documentation

rust/AGENTS.md

qodo-code-review · 2026-04-27T01:04:09Z

Code Review by Qodo

🐞 Bugs (1) 📘 Rule violations (1)

1. Missing rust:update task 🐞 Bug ≡ Correctness

Description

The PR deletes the rust:update rake task, but Rakefile still invokes it in release_updates,
which will fail at runtime with an unknown task error. This breaks the release preparation workflow
when running rake release_updates.

Code

rake_tasks/rust.rake[L15-30]

-desc 'Update the rust lock files'
-task :update do
-  # The first repin after a version bump can fail due to a stale checksum in
-  # Cargo.Bazel.lock; a second run lets Bazel reconcile and succeeds.
-  puts 'pinning cargo versions'
-  begin
-    Bazel.execute('fetch', ['--repo_env=CARGO_BAZEL_REPIN=true'], '@crates//:all')
-  rescue RuntimeError
-    puts 'repin failed, retrying...'
-    Bazel.execute('fetch', ['--repo_env=CARGO_BAZEL_REPIN=true'], '@crates//:all')
-  end
-end
-
-desc 'Pin Rust dependencies'
-task pin: :update
-

Evidence

Rakefile still calls Rake::Task['rust:update'].invoke as part of release_updates, but
rake_tasks/rust.rake no longer defines any task :update (only
build/format/lint/changelogs/version remain). Therefore, rake release_updates will raise “Don't
know how to build task 'rust:update'”.

Rakefile[104-126]
rake_tasks/rust.rake[9-51]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

### Issue description
`rake release_updates` invokes `rust:update`, but this PR removed the `rust:update` task definition from `rake_tasks/rust.rake`, so the release workflow will now fail with an unknown-task error.

### Issue Context
With the switch to `rules_rs`, there is no longer a Bazel-specific Rust lockfile repin step, so the old `rust:update` task was deleted. The top-level release task still expects it to exist.

### Fix Focus Areas
- Rakefile[112-122]
- rake_tasks/rust.rake[9-25]

### Suggested fix
Remove `Rake::Task['rust:update'].invoke` from the `release_updates` task (or reintroduce a `rust:update` task as a backward-compatible no-op if you still want the task name to exist).

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

2. Removed rust:update rake task 📘 Rule violation ⚙ Maintainability

Description

The PR deletes the rust:update and rust:pin rake tasks without first providing a deprecation
shim/message pointing users to the new workflow. This can break existing contributor automation and
violates the requirement to deprecate public functionality before removal with clear alternatives.

Code

rake_tasks/rust.rake[L15-30]

-desc 'Update the rust lock files'
-task :update do
-  # The first repin after a version bump can fail due to a stale checksum in
-  # Cargo.Bazel.lock; a second run lets Bazel reconcile and succeeds.
-  puts 'pinning cargo versions'
-  begin
-    Bazel.execute('fetch', ['--repo_env=CARGO_BAZEL_REPIN=true'], '@crates//:all')
-  rescue RuntimeError
-    puts 'repin failed, retrying...'
-    Bazel.execute('fetch', ['--repo_env=CARGO_BAZEL_REPIN=true'], '@crates//:all')
-  end
-end
-
-desc 'Pin Rust dependencies'
-task pin: :update
-

Evidence

PR Compliance ID 7 requires public functionality to be deprecated (with a message pointing to
alternatives) before removal. The diff removes the desc 'Update the rust lock files' / `task
:update and desc 'Pin Rust dependencies' / task pin: :update` definitions entirely, with no
deprecation alias retained.

AGENTS.md
rake_tasks/rust.rake[15-30]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
The rake tasks `rust:update` and `rust:pin` were removed without a deprecation period or a message pointing users to the new rules_rs-based workflow.

## Issue Context
Some contributors/automation may still call these tasks. The compliance requirement expects a deprecation step that clearly communicates the replacement.

## Fix Focus Areas
- rake_tasks/rust.rake[15-30]

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

dzbarsky · 2026-04-27T01:04:16Z

  Bazel.execute('build', args, '//rust:selenium-manager')
 end

-desc 'Update the rust lock files'


i'm not familiar with rake, is there anything additional that needs to be done here?

This should be fine, I think.

dzbarsky · 2026-04-27T01:05:18Z

+    ],
+    use_experimental_platforms = True,
+)
+crate.annotation(


rules_rs has recommended annotations for these to swap to rules_cc based builds, but I kept things as they were for this change

qodo-code-review · 2026-04-27T01:07:20Z

  Bazel.execute('build', args, '//rust:selenium-manager')
 end

-desc 'Update the rust lock files'


1. Missing rust:update task 🐞 Bug ≡ Correctness

The PR deletes the rust:update rake task, but Rakefile still invokes it in release_updates, which will fail at runtime with an unknown task error. This breaks the release preparation workflow when running rake release_updates.

Agent Prompt

### Issue description `rake release_updates` invokes `rust:update`, but this PR removed the `rust:update` task definition from `rake_tasks/rust.rake`, so the release workflow will now fail with an unknown-task error. ### Issue Context With the switch to `rules_rs`, there is no longer a Bazel-specific Rust lockfile repin step, so the old `rust:update` task was deleted. The top-level release task still expects it to exist. ### Fix Focus Areas - Rakefile[112-122] - rake_tasks/rust.rake[9-25] ### Suggested fix Remove `Rake::Task['rust:update'].invoke` from the `release_updates` task (or reintroduce a `rust:update` task as a backward-compatible no-op if you still want the task name to exist).

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

Removing the rust:update call, do we need to keep rust:update as a no-op to avoid breaking workflows or is it fine to remove?

rust:update is still called in release.yml and pre-release.yml workflows. It would be better to update those instead of keeping it as a no-op.

AutomatedTester · 2026-04-27T08:55:28Z

@dzbarsky could you sign the CLA before we can look to merge it?

dzbarsky · 2026-04-27T20:40:31Z

@dzbarsky could you sign the CLA before we can look to merge it?

yep, all good!

shs96c

I like the idea. Just a question.... Also, was this tested on macOS?

shs96c · 2026-04-27T21:57:21Z

  Bazel.execute('build', args, '//rust:selenium-manager')
 end

-desc 'Update the rust lock files'


This should be fine, I think.

shs96c · 2026-04-27T21:59:02Z

 # For build stamping
-build --enable_platform_specific_config
+common --enable_platform_specific_config
+common:linux --host_platform=//:local_linux_gnu


Why do we need these changes? The local cc_toolchain setup should already have set these to the right values. I also notice that macos is skipped.

it's because rules_rs, unlike rules_rust, supports multiple target triples per OS (*-linux-gnu and *-linux-musl, *-windows-gnullvm, *-windows-gnu, *-windows-msvc). It was not possible to target musl and non-msvc windows in rules_rust. However, this means there's an extra constraint needed to distinguish these targets, and since we need to also build targeting the host platform (for proc macros and cfg=exec targets like build scripts), we need to specify the constraint on the host as well.

Macos doesn't have these variants, hence it doesn't need the extra configuration! (and yes this was tested on macos)

OK. Thanks for clarifying.

cgoldberg · 2026-04-28T00:13:55Z

  Bazel.execute('build', args, '//rust:selenium-manager')
 end

-desc 'Update the rust lock files'


rust:update is still called in release.yml and pre-release.yml workflows. It would be better to update those instead of keeping it as a no-op.

dzbarsky · 2026-04-28T00:38:59Z

@cgoldberg thanks for pointing out the rust:update bit, I think I updated the callers but I'm not sure if I fully understand the templating that was going out there, mind sanity checking? I pushed those bits as a separate commit in this branch to make it easy!

cgoldberg · 2026-04-28T00:51:19Z

@dzbarsky yea, I think your workflow changes look correct. thanks.

dzbarsky · 2026-04-29T12:36:19Z

@cgoldberg I had a CI failure with the remote build using a platform without the constraint and thus failing toolchain resolution. Updated and repushed, could you help trigger CI? Would love a bit of help getting this in!

cgoldberg · 2026-04-29T13:00:02Z

could you help trigger CI?

It's running now

dzbarsky · 2026-04-29T13:04:50Z

could you help trigger CI?

It's running now

hmm i'm not sure how target selection is implemented but Rust job was skipped, that seems dangerous :)

cgoldberg · 2026-04-29T13:26:22Z

Rust job was skipped

I'm not sure how the target selection works either, and I can't figure out how to trigger the Rust job manually on your branch :/

cgoldberg · 2026-04-29T14:22:58Z

CI is failing all over the place because GitHub Actions is having issues right now. I'll try to figure it out once they get things stabilized.

selenium-ci added B-build Includes scripting, bazel and CI integrations C-rust Rust code is mostly Selenium Manager B-manager Selenium Manager labels Apr 27, 2026

dzbarsky commented Apr 27, 2026

View reviewed changes

qodo-code-review Bot reviewed Apr 27, 2026

View reviewed changes

AutomatedTester assigned shs96c Apr 27, 2026

[bazel] Swap to rules_rs for Rust build rules

6a0166d

dzbarsky force-pushed the zbarsky/rules_rs branch from 19bc642 to 6a0166d Compare April 27, 2026 14:04

shs96c reviewed Apr 27, 2026

View reviewed changes

cgoldberg requested changes Apr 28, 2026

View reviewed changes

Fix CI rust:update calls

a6bbadf

cgoldberg and others added 2 commits April 28, 2026 08:30

Merge branch 'trunk' into zbarsky/rules_rs

0c591fb

rbe platforms?

28535b4

Merge branch 'trunk' into zbarsky/rules_rs

30276f2

Merge branch 'trunk' into zbarsky/rules_rs

5eaf628

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dzbarsky commented Apr 27, 2026

💥 What does this PR do?

🔧 Implementation Notes

🤖 AI assistance

💡 Additional Considerations

🔄 Types of changes

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qodo-code-review Bot commented Apr 27, 2026

Review Summary by Qodo

Walkthroughs

File Changes

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dzbarsky commented Apr 28, 2026

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