Add temp-file and Cargo-unit cleaners, reclaiming without external tools

[UnbreakableMJ]

Vacuum could not cover the workflow it was built to replace. Reclaiming disk space still meant dropping to a shell for sudo rm -r /tmp/*, a system-wide nix-collect-garbage, a time-based journalctl --vacuum, and cargo-sweep.

Two new cleaners, both executing nothing

temp-files (new category) is the safe counterpart to sudo rm -r /tmp/*, which destroys other users' files and the live state of running processes. An entry under /tmp, /var/tmp, or $TMPDIR is offered only when it is not a symlink, is owned by the invoking user, has gone untouched for seven days, and is not session state (.X11-unix, systemd-private-*, .Trash-*, …). Root-owned leftovers stay out of scope and go to a printed sudo systemd-tmpfiles --clean.

cargo-prune removes dead build units from inside a Cargo target/, so a project still in use keeps its warm cache. It replaces a cargo-sweep shell-out that could never have worked here:

• cargo-sweep is unmaintained (its README says so).
• It needs cargo metadata, rustup toolchain list, and rustc -vV, none of which run on a Nix- or Guix-managed toolchain — cargo-sweep sweep --dry-run --installed errors out on the maintainer's own machine.
• Its --time mode reads atime, its oldest open bug: under relatime Cargo does not bump atime on artifacts it reuses, so it deletes warm caches.

Instead: target dirs are found by CACHEDIR.TAG; units are grouped by the "rustc" hash Cargo writes into each fingerprint, and the group with the most recent activity is the toolchain in use; freshness comes from invoked.timestamp. The incremental cache — ~30% of a target dir's bytes and something cargo-sweep never reclaims — is offered separately. A profile whose .cargo-lock is held by a running build is skipped.

Package-manager GC also gains system-wide nix-collect-garbage -d --verbose, journalctl --vacuum-time=7d, and systemd-tmpfiles --clean, all as printed sudo lines.

Core contract changes, required rather than incidental

• Cleaner::extra_roots — /tmp is outside $HOME, so every temp candidate would have been refused with OUTSIDE_ROOTS. The widened set applies only when that cleaner is selected; denylist and symlink guards untouched.
• Candidate::trash_ok — a path under /tmp trashes into /tmp/.Trash-$uid on the same filesystem and frees nothing. These purge instead, with the reason reported, never silently. --apply still required.
• Target::Batch — one logical reclaim spanning many paths. The safety gate runs over every path before any is removed, so a batch is refused whole rather than half-applied.

Sizes now count a hardlinked inode once; Cargo hardlinks its artifacts, so naive summing over-reported this workspace by ~12% and would have claimed the same bytes twice.

Frontends group by category rather than by cleaner (a latent bug: a second cleaner in a category produced duplicate JSON groups and duplicate headings). --cleaner selects one where candidates deliberately overlap; --stale-days and a stale_days config key set the window.

Verification

The toolchain-hash correspondence was proven before anything depended on it: hashing the -vV text Cargo stores in .rustc_info.json reproduces the fingerprint value exactly — 9571511559510505644 for rustc 1.95.0 and 125055456796404090 for 1.97.1, matching every fingerprint in the respective target dirs.

End to end, a crate was built with 1.95.0 then 1.97.1 to create two real toolchain groups in one target dir. Pruning the stale group left the live group and the unhashed binary intact, and the rebuild reported Fresh itoa / Fresh e2e — zero recompilation.

Gate: cargo fmt --check, clippy --workspace --all-targets -D warnings, 82 tests, reuse lint, makeinfo with no warnings.

🤖 Generated with Claude Code

https://claude.ai/code/session_01FCJbPm4FWS99y9utbUe13z

[chatgpt-codex-connector]

You have reached your Codex usage limits for code reviews. You can see your limits in the Codex usage dashboard.
To continue using code reviews, you can upgrade your account or add credits to your account and enable them for code reviews in your settings.