chore(paths): route fbuild-deploy tool paths through fbuild-paths

[zackees]

First ratchet batch for #1349. Allowlist 48 → 43; all five fbuild-deploy
entries are gone.

The drift the ratchet was for

Five tool resolvers — lpc21isp, probe-rs, wchisp, wlink, and the LPC-Link2
debugger assets — each hand-rolled ~/.fbuild/{dev|prod}/tools. All five
disagreed with fbuild-paths about what dev mode is:

	test	with FBUILD_DEV_MODE=0
the five copies	var_os("FBUILD_DEV_MODE").is_some()	dev
fbuild_paths::is_dev_mode()	var(..) == "1"	prod

So an explicit opt-out sent every managed tool to the dev tree while every
other fbuild path stayed in prod. A tool installed exactly where fbuild's own
hint said to install it would then go on being not-found — and the hint
hardcoded prod, so under FBUILD_DEV_MODE=1 it named a directory the
resolver was not searching either.

The new test in lpc.rs fails on the old code with precisely that split:

assertion `left == right` failed: FBUILD_DEV_MODE="0" must resolve the same tools dir as fbuild-paths
  left: Some("C:\Users\niteris\.fbuild\dev\tools")
 right: Some("C:\Users\niteris\.fbuild\prod\tools")

This is the failure mode #1349 predicted, found by removing the duplication
rather than by hitting it in the field. It is a behavior change: with
FBUILD_DEV_MODE set to anything other than 1, managed tools now resolve
under prod, consistent with the rest of fbuild.

New in fbuild-paths

The call sites re-derived the path because the accessor they needed did not
exist — get_fbuild_root() panics when the home directory cannot be
determined, and these resolvers return Option/Result on purpose so a
home-less environment stays diagnosable rather than becoming a crash.

• try_get_fbuild_root / try_get_tools_dir — the Option-returning forms
• get_tools_dir / TOOLS_DIR_NAME — the managed-tools location itself
• tools_dir_label — the ~/.fbuild/{dev|prod}/tools spelling for
  diagnostics, so an install hint names the tree fbuild will actually search

Verification

The lint is live on these files, not merely silent: with the allowlist entries
removed, a canary ".fbuild/build" literal reintroduced into wlink.rs fails
the build —

error: raw '.fbuild' path literal: use fbuild_paths (FBUILD_DIR_NAME, …)
error: could not compile `fbuild-deploy` (lib) due to 1 previous error

— and passes with the canary removed. soldr cargo test -p fbuild-deploy: 286
passed, 0 failed. Lint crate version bumped so the cached .so is rebuilt
against the shrunk allowlist.

Also hoists the module's existing env-var mutex over the two tests that now
read a FBUILD_DEV_MODE-derived path, with a drop-guard restore, so a failing
assertion cannot leave a flipped value behind for a sibling test.

[coderabbitai]

Warning

Review limit reached

@zackees, you've reached your PR review limit, so we couldn't start this review.

Next review available in: 30 minutes

Limit details: You’ve used the included review currently available.

You've used all free OSS reviews for now. Wait for the free limit to reset to keep reviewing this public repository.

How can I continue?

Wait for the limit to reset, then comment @coderabbitai review or push new commits to the PR.

An organization admin can change what happens after included review limits in Billing.

How do review limits work?

CodeRabbit enforces per-developer PR review limits within each organization.

For paid Pro and Pro+ reviews, CodeRabbit uses a developer's included PR review attempts over the past 7 days to set the current hourly allowance. At typical activity levels, the full plan allowance applies. Higher sustained activity can lower the allowance until earlier attempts leave the 7-day window.

Please refer docs for additional details.

Review details

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: cb1dac00-3744-4526-a021-1ff14e7fe70c

📥 Commits

Reviewing files that changed from the base of the PR and between b6f7eb9 and 7ab8c11.

📒 Files selected for processing (8)

• crates/fbuild-deploy/src/lpc.rs
• crates/fbuild-deploy/src/lpc_debugger_reflash.rs
• crates/fbuild-deploy/src/probe_rs.rs
• crates/fbuild-deploy/src/wchisp.rs
• crates/fbuild-deploy/src/wlink.rs
• crates/fbuild-paths/src/lib.rs
• dylints/ban_raw_fbuild_path/Cargo.toml
• dylints/ban_raw_fbuild_path/src/allowlist.txt

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}