Complete just completions: Justfile recipe generator

[warp-agent-staging]

Summary

just <TAB> offered filesystem paths instead of Justfile recipes. json/just.json already described just's flags, but its recipe arguments carried Fig's JavaScript generators.script / postProcess — which Warp ignores — and there was no Rust generator behind them, so the completer fell through to the path templates.

This adds the missing Rust generators and points the spec at them:

• src/generators/just.rs — a recipes generator and a variables generator, registered in generators/mod.rs.
  • recipes prefers just --unstable --dump --dump-format json (carries doc comments and the private flag), falling back to just --list and then just --summary for older just releases. Private recipes (leading _ or [private]) are omitted, matching just's own listing behavior, and a recipe's doc comment becomes its description (Just recipe when it has none).
  • Recipes get Priority::Global(Importance::More(Order(80))), the same rank make targets use, so they sort above the path suggestions for the same position.
  • Every tier of the command is only reached when the previous one exits non-zero, so no Justfile, an unreadable Justfile, or just not being installed all end with empty stdout and an empty suggestion list — never a panic.
• json/just.json — the variadic recipe argument and --show now use "generatorName": "recipes"; --set's variable argument uses "generatorName": "variables". The Fig JS generator blobs are removed. Flags and options are untouched, so they stay completable.

Verification

script/presubmit (prettier, cargo fmt --check, cargo clippy -D warnings, cargo test) passes — 115 tests, 9 new.

Regression test: test_just_spec_wires_recipe_arguments_to_the_recipes_generator asserts the spec's recipe arguments resolve to the recipes generator. It fails on main (assertion failed: recipe_argument.argument_types.contains(&recipes)) and passes with this change.

The remaining tests cover the post-processing against output captured from a real just 1.58.0 run over a Justfile with documented, undocumented, parameterized, grouped, _-private and [private]-attribute recipes:

• test_dump_json_lists_public_recipes_with_docs — public recipes with their docs, both private recipes dropped.
• test_dump_json_recipes_outrank_path_suggestions — recipes carry a global priority.
• test_list_output_lists_recipes_and_skips_group_headings — --list parsing, [group] headings skipped.
• test_list_output_with_only_private_recipes_is_empty, test_list_output_keeps_a_hash_inside_a_parameter_default, test_summary_output_lists_recipes.
• test_unusable_output_yields_no_suggestions — empty, whitespace-only, and malformed output all yield zero suggestions.
• test_variables_are_listed.

The generator's shell command was also run end to end against just 1.58.0: it returns the JSON dump in a Justfile directory, and exits non-zero with empty stdout both with no Justfile present and with just off $PATH.

No computer-use proof is attached: this repo is a headless library with no rendered surface of its own, and the change cannot be seen in the client until the warp pin below moves.

Follow-up required to ship

warpdotdev/warp pins warp-command-signatures by git rev in its root Cargo.toml. That rev must be bumped after this PR merges for the completions to reach the client; that bump is deliberately not part of this PR.

Originating thread: https://warpdev.slack.com/archives/C0BDQDW8V5E/p1785982310270809
Source issue: warpdotdev/warp#1906

Conversation: https://staging.warp.dev/conversation/e450180d-3523-4c00-8d34-59a96e0edf7f
Run: https://oz.staging.warp.dev/runs/019fd4e0-3937-72e5-9624-4be092502e6f

This PR was generated with Oz.

[oz-for-oss]

@warp-agent-staging[bot]

I'm starting a first review of this pull request.

You can view the conversation on Warp.

I completed the review and no human review was requested for this pull request.

Comment /oz-review on this pull request to retrigger a review (up to 3 times on the same pull request).

Powered by Oz

[oz-for-oss]

Overview

This PR adds Rust-backed dynamic generators for Justfile recipes and variables, then wires the just signature to use them for recipe and variable arguments.

Concerns

• The variadic recipe argument is now backed by an unconditional recipe-name generator, which drops the previous arity/trigger behavior for parameterized recipes.

Verdict

Found: 0 critical, 1 important, 0 suggestions

Request changes

Comment /oz-review on this pull request to retrigger a review (up to 3 times on the same pull request).

Powered by Oz

[oz-for-oss]

⚠️ [IMPORTANT] This variadic argument now invokes the recipe generator for every token, but the removed Fig generator used arity/trigger logic to avoid suggesting another recipe while the previous recipe still needed parameters. For a Justfile like deploy env:, just deploy <TAB> will suggest recipe names instead of allowing the env value; port the arity check before wiring this unconditional generator here.