feat(install.sh): uninstall + rc-file hygiene (#741)

[LukasWodka]

Closes #741.

Stacks on #61 (branched off fix/install-path-persist). The diff below includes #61's commit (fix(install.sh): persist PATH to the shell rc) until #61 merges — that's expected for a stacked PR. Rebase onto develop after #61 lands and the diff collapses to just this change. Review the second commit (feat(install.sh): add --uninstall + harden rc-file mutation) for the #741 work.

Summary

#61 made the installer mutate the user's shell rc — it appends a marked PATH block (# Added by the tracebloc CLI installer + an export PATH=… / fish_add_path line) on the unprivileged ~/.local/bin fallback. That was the right fix, but mutating dotfiles creates obligations the installer didn't yet meet. This PR closes them: an uninstall path, and safety around managed/symlinked/read-only rc files.

What changed (scripts/install.sh)

• --uninstall flag — removes the tracebloc binary from the prefix (and the ~/.local/bin fallback, so it cleans up regardless of which path install took) and strips only our marked block from the rc, restoring it byte-identical. Takes no network.
  • Portable editing — temp file + mv + awk (the repo's existing sync-schema.sh convention). No sed -i, whose -i semantics differ between GNU and BSD/macOS.
  • Removes the leading blank-line separator too. fix(install.sh): persist PATH to the shell rc (parity with install.ps1) #61's append writes \n + marker + path line, so the block is effectively three lines. Stripping only the two visible lines orphans a blank line — the round-trip bats test caught this. The awk uses one-line lookbehind to drop a single preceding blank separator (only if it is blank — real content is kept).
  • Multi-rc scan — uninstall checks every candidate rc (.zshrc, .bashrc, .bash_profile, fish config, .profile), so it finds the block even if the user installed under a different shell or has since switched shells.
  • Idempotent — running it on an already-clean system is a no-op that still exits 0.
• Hardened the append path (the part fix(install.sh): persist PATH to the shell rc (parity with install.ps1) #61 added):
  • Symlinked / read-only / managed rc (chezmoi, dotfiles repo, Nix home-manager) is detected — the installer advises the user with the exact line to add instead of writing through the link or failing silently. Non-fatal.
  • $SHELL unset / exotic (csh, tcsh, nu) now falls back to advice rather than guessing ~/.profile (which a fresh non-login bash never reads).
• Refactor — rc routing (rc_for_shell), the PATH line (path_line_for_shell), the managed-rc probe (rc_is_managed), append (append_path_to_rc), and strip (strip_rc_block) are now shared, named functions, and the marker string is a single RC_MARKER constant. Install and uninstall cannot drift on the marker or the target file. Existing install idempotency (fix(install.sh): persist PATH to the shell rc (parity with install.ps1) #61's "skip if rc already references the dir") is preserved.

Why

Per #741: mutating dotfiles without an uninstall leaves the line orphaned; and an append that writes through a symlink or a read-only/managed rc can fail silently or pollute version control. Both are addressed. The original report behind #61 came from a field deployment on Ubuntu 24.04.

Test plan

New scripts/tests/install.bats (bats-core) — 17 tests, all green:

• append → --uninstall round-trips the rc byte-identical (with trailing newline, with a trailing blank line, and for an empty file). The one documented non-identical case — an rc whose last line lacks a trailing newline gains one (POSIX-correct, harmless) — is asserted explicitly.
• read-only rc → advises, file untouched.
• symlinked rc → advises on both append and strip, link target untouched, symlink not clobbered.
• unset / exotic $SHELL → generic advice, no wrong-file write; rc_for_shell returns non-zero; known shells route correctly.
• idempotency — append x3 → one block; strip x2 → clean, exit 0; strip on a never-touched rc leaves it identical.
• end-to-end --uninstall via the real script — removes binary + block, clean no-op on a clean system, finds the block in a non-routed rc.

The suite sources install.sh behind a TRACEBLOC_INSTALL_SH_SOURCE_ONLY gate so the pure rc functions run without any download; the end-to-end tests execute the real script (uninstall takes no network).

Verified locally / Needs CI

Verified locally:

• bash -n scripts/install.sh — OK
• sh -n scripts/install.sh — OK (POSIX /bin/sh, no bashisms, matching the script's contract)
• shellcheck -s sh scripts/install.sh — clean (shellcheck 0.11.0)
• bats scripts/tests/install.bats — 17/17

Needs CI: build.yml only exercises the Go code — there is no shell-lint or bats step today, so neither #61's append nor this change is covered by CI. A small job (shellcheck + bats scripts/tests/) would guard the installer going forward. Not added here to avoid bundling CI infra into a behavior PR — happy to follow up if wanted.

Notes

• POSIX /bin/sh throughout (the script is piped via curl … | sh on distros that may lack bash).
• install.ps1 (Windows) already persists PATH and is out of scope; only install.sh mutates a Unix rc, so only it needs the uninstall/hygiene work.
• bats is required to run the suite (brew install bats-core / apt install bats).

[LukasWodka]

👋 Heads-up — Code review queue is at 17 / 8

Above the WIP limit. The team convention is to review existing PRs before opening new work.

Open PRs currently in Code review (oldest first):

• averaging-service#102 — chore(kanban): declare staging as prod-truth branch via .kanban.yml · author: @LukasWodka · no reviewer assigned
• averaging-service#103 — fix(averaging): correctness foundations — DP, shape guard, sklearn weighting, bounded ensembles (dataset push: tabular pre-flight silently collapses duplicate header columns and accepts zero-data-row CSVs #73) · author: @LukasWodka · reviewer: @shujaatTracebloc
• averaging-service#98 — ci: add fr-gate caller workflow · author: @LukasWodka · no reviewer assigned
• backend#732 — feat(experiments): add per-experiment aggregation_strategy field (#730) · author: @LukasWodka · reviewer: @saqlainsyed007, @shujaatTracebloc
• backend#735 — fix(flops): atomic flops_used + fire stop once on threshold crossing (#733) · author: @saadqbal · no reviewer assigned
• cli#61 — fix(install.sh): persist PATH to the shell rc (parity with install.ps1) · author: @LukasWodka · reviewer: @saadqbal
• client#207 — test(charts): add helm-unittest suite for ingestion-authz-configmap · author: @saadqbal · no reviewer assigned
• client#211 — fix(installer): bound the apt dpkg-lock wait so a held lock can't hang the install (#210) · author: @saadqbal · no reviewer assigned
• data-ingestors#146 — test(schema): lock category enum to the engine's TaskCategory (anti-drift) · author: @LukasWodka · reviewer: @saadqbal
• data-ingestors#148 — Develop to prod · author: @divyasinghds · reviewer: @saadqbal

Pull from review before opening new work. (This is a nudge from the kanban WIP check, not a block.)

[LukasWodka]

Rebased against current develop (2026-06-08).

What changed during rebase:

• Dropped the first commit (5ff1fa6 — PATH persist) — it's already in prod via fix(install.sh): persist PATH to the shell rc (parity with install.ps1) #61 + fix(install.sh): tighten PATH idempotency + persist user-local PREFIX (Bugbot on #61) #65 (Bugbot follow-up).
• Resolved scripts/install.sh conflict by taking the shipped inline PATH-handling version. The append_path_to_rc() function refactor this PR originally introduced has been superseded by an inline implementation in develop.
• Kept the unique value: --uninstall flag handling, RC_MARKER env var, the matching --uninstall usage docs, and the 601-line scripts/tests/install.bats test suite.

Ready for review.

[LukasWodka]

Closing as stale/superseded (Lukas's call, board hygiene 2026-07-07): stacked on #61 which merged a month ago, predates the tb alias (cli#142) its rc-cleanup would now need to handle, and the accepted §15 amendment (#139, A4) moves offboarding ownership to client delete — the binary-uninstall + rc-hygiene sliver should be re-cut small against that world (tracked via #139's follow-ups). The portable rc-editing approach in here (temp file + mv + awk, marked-block strip) is worth lifting when it's rebuilt.