fix(lib): validate choices for variadic args and flags by jdx · Pull Request #520 · jdx/usage

jdx · 2026-02-24T17:06:17Z

Summary

Variadic arguments and flags with choices were not being validated — any value was accepted
Added choice validation to both variadic code paths (positional args and flags) in parse.rs, matching the existing non-variadic behavior
Added 4 test cases covering valid and invalid choices for both variadic args and flags

Test plan

cargo test -p usage-lib --test parse — all 32 tests pass
cargo clippy -p usage-lib --all-features -- -D warnings — clean

🤖 Generated with Claude Code

Note

Low Risk
Narrow change to CLI parsing validation: variadic args/flags with choices now error where they previously accepted any value, which may affect callers relying on permissive behavior.

Overview
Fixes a parsing gap where variadic positional args and variadic flag values (var=true) were not being validated against declared choices.

parse.rs now enforces choices for both variadic arg capture and variadic flag value capture, mirroring the existing non-variadic behavior (including --help/-h handling). Adds tests ensuring valid values pass and invalid values produce the expected error messages for both variadic args and flags.

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gemini-code-assist · 2026-02-24T17:07:27Z

Summary of Changes

Hello @jdx, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a missing validation step for variadic arguments and flags. It ensures that when choices are defined, only those values are accepted, mirroring the behavior of non-variadic arguments. The changes include modifications to parse.rs and the addition of new test cases to verify the fix.

Highlights

Choice Validation: Implemented choice validation for variadic arguments and flags, ensuring that only allowed values are accepted.
Code Modification: Modified parse.rs to include choice validation in the variadic code paths for both positional arguments and flags.
Test Cases: Added four new test cases to cover valid and invalid choices for variadic arguments and flags.

Changelog

lib/src/parse.rs
- Added choice validation for variadic flags.
- Added choice validation for variadic arguments.
lib/tests/parse.rs
- Added test case for valid variadic argument choices.
- Added test case for invalid variadic argument choices.
- Added test case for valid variadic flag choices.
- Added test case for invalid variadic flag choices.

Activity

The author, jdx, has addressed issue #8334 by adding validation for choices in variadic arguments and flags.
The pull request includes updates to parse.rs and the addition of new test cases.
The test plan includes running cargo test -p usage-lib --test parse and cargo clippy -p usage-lib --all-features -- -D warnings.

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gemini-code-assist

Code Review

This pull request introduces crucial choice validation for variadic arguments and flags, enhancing the robustness and correctness of the parsing logic. The addition of comprehensive test cases for both valid and invalid scenarios is commendable and ensures the new functionality works as expected. There is a minor inconsistency in error handling for variadic flags when a help argument is encountered, which should be addressed to maintain consistent user experience.

gemini-code-assist · 2026-02-24T17:08:45Z

+                    if let Some(choices) = &arg.choices {
+                        if !choices.choices.contains(&w) {
+                            bail!(
+                                "Invalid choice for option {}: {w}, expected one of {}",
+                                flag.name,
+                                choices.choices.join(", ")
+                            );
+                        }
+                    }


The choice validation for variadic flags is missing the is_help_arg check that is present in the non-variadic flag validation path (lines 495-500). This inconsistency could lead to a user receiving an "Invalid choice" error when attempting to request help for a variadic flag, instead of the expected help message. It's important to handle help arguments gracefully in all validation paths.

Suggested change

if let Some(choices) = &arg.choices {

if !choices.choices.contains(&w) {

bail!(

"Invalid choice for option {}: {w}, expected one of {}",

flag.name,

choices.choices.join(", ")

);

}

}

if let Some(choices) = &arg.choices {

if !choices.choices.contains(&w) {

if is_help_arg(spec, &w) {

out.errors

.push(render_help_err(spec, &out.cmd, w.len() > 2));

return Ok(out);

}

bail!(

"Invalid choice for option {}: {w}, expected one of {}",

flag.name,

choices.choices.join(", ")

);

}

}

Copilot

Pull request overview

This PR fixes a bug where variadic arguments and flags with choices constraints were not being validated, allowing any value to be accepted. The fix adds choice validation to both variadic code paths in the parser, matching the behavior of non-variadic arguments and flags.

Changes:

Added choice validation for variadic flags (parse.rs lines 476-484)
Added choice validation for variadic arguments (parse.rs lines 516-529)
Added 4 test cases covering valid and invalid choices for both variadic args and flags

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
lib/src/parse.rs	Added choice validation logic for variadic flags and arguments
lib/tests/parse.rs	Added test cases for variadic argument and flag choice validation

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Copilot · 2026-02-24T17:09:32Z

+                    if let Some(choices) = &arg.choices {
+                        if !choices.choices.contains(&w) {
+                            bail!(
+                                "Invalid choice for option {}: {w}, expected one of {}",
+                                flag.name,
+                                choices.choices.join(", ")
+                            );
+                        }


The variadic flag choice validation is missing help argument handling that exists in the non-variadic flag path (lines 495-498). When a user provides an invalid choice for a variadic flag, they should still be able to request help with -h or --help. Add the same help check here before the bail! call to match the pattern used in non-variadic flags and variadic args.

Variadic arguments and flags with `choices` were not being validated, allowing any value to pass. Added choice validation to both variadic code paths matching the existing non-variadic behavior. Closes jdx/mise#8334 Co-Authored-By: Claude Opus 4.6 <[email protected]>

codecov · 2026-02-24T23:01:02Z

Codecov Report

❌ Patch coverage is 7.40741% with 25 lines in your changes missing coverage. Please review.
✅ Project coverage is 75.83%. Comparing base (5fb3420) to head (88fbc18).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/src/parse.rs	7.40%	10 Missing and 15 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #520      +/-   ##
==========================================
- Coverage   77.88%   75.83%   -2.05%     
==========================================
  Files          48       48              
  Lines        6660     6721      +61     
  Branches     6660     6721      +61     
==========================================
- Hits         5187     5097      -90     
- Misses       1109     1153      +44     
- Partials      364      471     +107

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@jdx

### 🐛 Bug Fixes - **(lib)** validate choices for variadic args and flags by [@jdx](https://github.com/jdx) in [#520](#520) ### 🛡️ Security - require AI disclosure on GitHub comments by [@jdx](https://github.com/jdx) in [#519](#519) ### 📦️ Dependency Updates - update autofix-ci/action action to v1.3.3 by [@renovate[bot]](https://github.com/renovate[bot]) in [#515](#515) - update rust crate clap to v4.5.60 by [@renovate[bot]](https://github.com/renovate[bot]) in [#516](#516) - lock file maintenance by [@renovate[bot]](https://github.com/renovate[bot]) in [#518](#518)

This MR contains the following updates: | Package | Update | Change | |---|---|---| | [usage](https://github.com/jdx/usage) | patch | `2.18.0` → `2.18.1` | MR created with the help of [el-capitano/tools/renovate-bot](https://gitlab.com/el-capitano/tools/renovate-bot). **Proposed changes to behavior should be submitted there as MRs.** --- ### Release Notes <details> <summary>jdx/usage (usage)</summary> ### [`v2.18.1`](https://github.com/jdx/usage/blob/HEAD/CHANGELOG.md#2181---2026-02-24) [Compare Source](jdx/usage@v2.18.0...v2.18.1) ##### 🐛 Bug Fixes - **(lib)** validate choices for variadic args and flags by [@jdx](https://github.com/jdx) in [#520](jdx/usage#520) ##### 🛡️ Security - require AI disclosure on GitHub comments by [@jdx](https://github.com/jdx) in [#519](jdx/usage#519) ##### 📦️ Dependency Updates - update autofix-ci/action action to v1.3.3 by [@renovate\[bot\]](https://github.com/renovate\[bot]) in [#515](jdx/usage#515) - update rust crate clap to v4.5.60 by [@renovate\[bot\]](https://github.com/renovate\[bot]) in [#516](jdx/usage#516) - lock file maintenance by [@renovate\[bot\]](https://github.com/renovate\[bot]) in [#518](jdx/usage#518) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Enabled. ♻ **Rebasing**: Whenever MR is behind base branch, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this MR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this MR, check this box --- This MR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).

Copilot AI review requested due to automatic review settings February 24, 2026 17:06

Copilot started reviewing on behalf of jdx February 24, 2026 17:06 View session

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Comment thread lib/src/parse.rs

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jdx force-pushed the fix/variadic-choice-validation branch from 82947f9 to 02510ea Compare February 24, 2026 17:09

jdx force-pushed the fix/variadic-choice-validation branch from 02510ea to 88fbc18 Compare February 24, 2026 22:22

jdx merged commit 2a9a12e into main Feb 24, 2026
7 checks passed

jdx deleted the fix/variadic-choice-validation branch February 24, 2026 22:26

mise-en-dev mentioned this pull request Feb 24, 2026

chore: release v2.18.1 #517

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BrewTestBot mentioned this pull request Feb 25, 2026

usage 2.18.1 Homebrew/homebrew-core#269282

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fix(lib): validate choices for variadic args and flags#520

fix(lib): validate choices for variadic args and flags#520
jdx merged 1 commit intomainfrom
fix/variadic-choice-validation

jdx commented Feb 24, 2026 •

edited by cursor Bot

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