fix(install): stop update_shell_rc from duplicating its PATH block forever

[yibocai-airbnb]

Summary

update_shell_rc()'s dedup check is a real, deterministic bug that affects every user who runs install.sh more than once (reinstall, --local, update, etc.).

The check compares the shell-expanded real home directory:

grep -qF "$HOME/.local/bin" "$rc"   # double-quoted -> bash expands $HOME first

against the line the function itself appends, which comes from a single-quoted variable:

local path_line='export PATH="$HOME/.local/bin:$PATH"'

That line lands in the rc file as the literal, unexpanded text $HOME/.local/bin — a literal dollar sign, never the real path. The dedup check can therefore never match the installer's own prior write, and every re-run appends another duplicate RC_MARKER + PATH block, unbounded, forever.

Concretely reproduced this against a real .zshrc accumulating 8 duplicate blocks from repeated installs over the course of normal use.

Fix

Check for RC_MARKER (the literal marker line we actually write, guaranteed present on any rc we've already patched) plus the other real spellings ~/.local/bin can take in a pre-existing rc file: literal $HOME/.local/bin, ~/.local/bin, and the fully-expanded real path. This fixes the never-matching re-run case while preserving the original intent — a genuinely pre-existing PATH entry (in any of these forms) is still recognized and skipped.

Tests

New tests/test_install_sh_rc_dedup.py — extracts update_shell_rc() verbatim out of install.sh via sed (so it always exercises the real current source, not a hand-copied approximation) and exercises it against a fake $HOME:

• single run patches exactly once
• re-running does not duplicate (the core regression guard — fails against the pre-fix code: verified locally by reverting just the fix and confirming 3/5 tests fail with the exact duplication behavior described above)
• 5 consecutive runs in one process still leave exactly one copy
• a pre-existing ~/.local/bin (tilde form) is recognized and not re-patched
• a pre-existing fully-expanded real-path form is recognized and not re-patched

No install.sh tests existed in the repo before this.

Test plan

• python3 -m pytest tests/test_install_sh_rc_dedup.py -v — 5/5 pass against the fix
• Reverted only the fix (kept the test) and confirmed 3/5 tests fail with the exact duplication bug described above
• bash -n install.sh — syntax OK

🤖 Generated with Claude Code

[github-actions]

Test Results

     5 files   1 018 suites   28m 1s ⏱️
15 867 tests 15 835 ✅ 22 💤 10 ❌
31 773 runs  31 697 ✅ 66 💤 10 ❌

For more details on these failures, see this check.

Results for commit d312a25.

[agentforce314]

LGTM. Thank you!