Use native Rust tests for Rust frontend by MikeMcQuaid · Pull Request #21805 · Homebrew/brew

MikeMcQuaid · 2026-03-22T19:26:56Z

add unit and CLI parity tests under rust/brew-rs
remove the Ruby cmd/brew_rs integration spec
call cargo directly in brew-rs.yml and gate benchmarks

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- add unit and CLI parity tests under rust/brew-rs - remove the Ruby cmd/brew_rs integration spec - call cargo directly in brew-rs.yml and gate benchmarks

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Pull request overview

Migrates Rust-frontend verification from a Ruby integration spec to native Rust unit + CLI parity tests, and updates CI to run those tests directly via Cargo while adding a benchmark regression gate.

Changes:

Remove the cmd/brew_rs Ruby integration spec and add Rust-native CLI parity tests under rust/brew-rs/tests.
Add/expand Rust unit tests for matcher, Homebrew helpers, and command logic (search/list).
Update brew-rs.yml to run cargo fmt/clippy/test directly and gate performance via rake benchmark:check (with artifact upload).

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
Library/Homebrew/test/cmd/brew_rs_spec.rb	Removes Ruby integration coverage for brew-rs dispatch/parity.
Library/Homebrew/rust/brew-rs/tests/cli.rs	Adds Rust CLI parity tests comparing Rust vs Ruby outputs.
Library/Homebrew/rust/brew-rs/src/matcher.rs	Adds unit tests for matcher parsing/matching behavior.
Library/Homebrew/rust/brew-rs/src/homebrew.rs	Adds unit tests for file/line utilities.
Library/Homebrew/rust/brew-rs/src/commands/search.rs	Adds unit tests for fuzzy vs plain match behavior.
Library/Homebrew/rust/brew-rs/src/commands/list.rs	Adjusts list output behavior + adds unit tests for keg/cask path resolution.
Library/Homebrew/rust/brew-rs/Rakefile	Enhances benchmarking to export JSON, summarize results, and fail CI on regression.
Library/Homebrew/rust/brew-rs/README.md	Updates build/check instructions away from `rake build/check` and away from `brew tests`.
Library/Homebrew/rust/brew-rs/AGENTS.md	Updates contributor instructions to use vendor-install + cargo commands and benchmark gate.
.github/workflows/brew-rs.yml	Switches workflow to cargo fmt/clippy/test, removes Ruby spec run, adds benchmark gating + artifacts.

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Copilot · 2026-03-22T19:31:54Z

Library/Homebrew/rust/brew-rs/src/commands/list.rs

    if args.len() == 1 {
-        let formulae = homebrew::installed_names(&cellar)?;
-        let casks = homebrew::installed_names(&caskroom)?;
-        homebrew::print_sections(&formulae, &casks);
+        let mut installed = homebrew::installed_names(&cellar)?;
+        installed.extend(homebrew::installed_names(&caskroom)?);
+        if !installed.is_empty() {
+            println!("{}", installed.join("\n"));
+        }


brew list in the Rust frontend now prints all installed formulae + casks as a single newline-joined list with no TTY headings/section separation. The Ruby implementation prints ohai "Formulae"/ohai "Casks" when $stdout.tty? (see Library/Homebrew/cmd/list.rb), so this is a user-visible parity regression when running interactively. Consider restoring TTY-aware section headers (and any spacing) while keeping the non-TTY output identical to Ruby for the CLI parity tests.

Copilot · 2026-03-22T19:31:55Z

Library/Homebrew/rust/brew-rs/README.md

 ## Build

 ```bash
-cd Library/Homebrew/rust/brew-rs
-rake build
+./bin/brew vendor-install brew-rs
 ```


The build instructions use ./bin/brew vendor-install brew-rs, but this README is located under Library/Homebrew/rust/brew-rs/ and the surrounding examples previously had you cd into that directory. As written, running this from Library/Homebrew/rust/brew-rs will fail because ./bin/brew won’t exist there. Please clarify the expected working directory (e.g., “from the repo root”) or adjust the path accordingly.

Copilot · 2026-03-22T19:31:55Z

Library/Homebrew/rust/brew-rs/AGENTS.md

+- Run `./bin/brew vendor-install brew-rs` to vendor the binary locally.
+- Run `cargo fmt --check`, `cargo clippy --all-targets --locked -- -D warnings`, and `cargo test --locked` from `Library/Homebrew/rust/brew-rs`.
 - Use `BREW_RS_STAGE_REPOSITORY=/path/to/Homebrew rake stage` to stage into another checkout.
 - Use `rake benchmark` for Ruby vs Rust benchmarks.
+- Use `rake benchmark:check` for the CI benchmark gate.


./bin/brew vendor-install brew-rs assumes the repository root as the working directory, but this guidance appears inside Library/Homebrew/rust/brew-rs/AGENTS.md where earlier instructions were explicitly run from within this directory. Please clarify “from the repo root” or update the command to a correct relative path from Library/Homebrew/rust/brew-rs.

carlocab · 2026-03-22T20:27:20Z

Library/Homebrew/rust/brew-rs/Rakefile

+      {
+        slug:         "list",
+        title:        "brew list",
+        ruby_command: shell_command(BREW, "list", env: common_env),
+        rust_command: shell_command(BREW, "list", env: rust_env),
+        runs:         5,
+        warmup:       2,
+      },


Note that an unqualified brew list will not call the Rust version, because we invoke the shell fast path here:

brew/Library/Homebrew/brew.sh

Lines 189 to 193 in 340e1e2

# falls back to cmd/list.rb on a non-zero return

list* | ls*)

source "${HOMEBREW_LIBRARY}/Homebrew/list.sh"

homebrew-list "$@" && exit 0

;;

To reach the Rust frontend, you need to do something like brew list <formula-name>.

Move brew-rs tests into Rust CI

6f9962a

- add unit and CLI parity tests under rust/brew-rs - remove the Ruby cmd/brew_rs integration spec - call cargo directly in brew-rs.yml and gate benchmarks

Copilot AI review requested due to automatic review settings March 22, 2026 19:26

Copilot started reviewing on behalf of MikeMcQuaid March 22, 2026 19:27 View session

Copilot AI reviewed Mar 22, 2026

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carlocab reviewed Mar 22, 2026

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Use native Rust tests for Rust frontend#21805

Use native Rust tests for Rust frontend#21805
MikeMcQuaid wants to merge 1 commit intomainfrom
rust-frontend-ci-tests

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	# falls back to cmd/list.rb on a non-zero return
	list* \| ls*)
	source "${HOMEBREW_LIBRARY}/Homebrew/list.sh"
	homebrew-list "$@" && exit 0
	;;

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