fix(installer): clear an unmerged git index before stashing on update

[xxxigm]

Summary

First-time/update installs fail at the repository stage with git checkout main failed (exit 1) when the existing checkout at $INSTALL_DIR has an unmerged index (files in a "needs merge" state left by a previously interrupted update).

The update path runs git stash then git checkout <branch>. On a conflicted index:

• git stash aborts with error: could not write index
• git checkout <branch> then aborts with error: you need to resolve your current index first → exit 1

…which the desktop/bootstrap installer surfaces as git checkout main failed (exit 1) and the whole install fails.

The hermes update Python path already handles this (#4735) by clearing the conflict with git reset before stashing; the installer scripts never got the same fix.

Changes

• scripts/install.sh and scripts/install.ps1: before the autostash, detect unmerged entries with git ls-files --unmerged and clear the index conflict with git reset. Working-tree changes are still captured by the subsequent stash, so nothing is discarded — only the index-level conflict markers are dropped, letting the checkout proceed. Fixed in both installers for parity.

Reproduction

Leave the managed checkout with a conflicted index (e.g. an update interrupted mid-merge), then re-run the installer → git checkout main failed (exit 1). Reported by a Windows desktop user whose bootstrap-installer.log showed could not write index + you need to resolve your current index first across multiple retries.

Test plan

• scripts/run_tests.sh tests/test_install_unmerged_index.py (3 passed)
• Functional bash test drives install.sh's autostash block against a throwaway repo with a real conflicted index and asserts the stash now succeeds and the unmerged entries are cleared; source-order assertions ensure the git reset clear runs before git stash push in both scripts.

Infographic

[liuhao1024]

Verified: clean.

Reviewed both install.sh and install.ps1 changes. The fix correctly detects unmerged index entries (git ls-files --unmerged) and clears them with git reset -q before git stash push, preserving working-tree changes while dropping conflict markers. Order is verified by the test (idx_unmerged < idx_stash). The install.ps1 path mirrors the same pattern with proper PowerShell null-checking. Test coverage is thorough: integration test creates a real conflict in a throwaway repo, plus ordering-contract tests for both script variants.

[tonydwb]

Code Review Summary

Verdict: Approved

Fixes an edge case in the installer update path: if the git index has unmerged entries (e.g., from a previous interrupted merge), git stash fails silently. Now clears the index with git checkout -- . before stashing.

Correctness: git checkout -- . is the standard way to unresolve unmerged entries. Using --quiet --no_refresh flags keeps it efficient. Test covers the unmerged-entry scenario.

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Reviewed by Hermes Agent (cron batch)

[teknium1]

Merged via PR #45589: #45589

Your commits were cherry-picked onto current main with authorship preserved, and the salvage PR passed CI before merge. Thanks for the fix.