fix(update): preserve --depth 1 on shallow installs during update

[JonthanaHanh]

Summary

The --check path correctly detects shallow repos and appends --depth 1 to fetch commands (lines 2238-2247), but the actual update path did a bare git fetch origin branch without depth args. On shallow installs (the default from the installer), this unshallows the repo and drags in the entire git history.

Problem

hermes update on a shallow git install triggers a full unshallow fetch (missing --depth 1 in the update path) and shows no progress output while doing it. The terminal sits at "Fetching updates..." for 20+ minutes because it's downloading 179,583+ objects.

Observed on a mainland-China network: 42 MB in ~9 minutes and nowhere near done, because the full repo history was being fetched when only the shallow boundary was needed.

Root cause

hermes_cli/update_cmd.py line 3749 (before this fix):

git_cmd + ["fetch", "origin", branch],   # no --depth 1

The --check path at line 2238-2247 correctly does:

is_shallow = (subprocess.run(git_cmd + ["rev-parse", "--is-shallow-repository"], ...).stdout.strip() == "true")
deppth_args = ["--depth", "1"] if is_shallow else []

But the actual update fetch did not reuse this logic.

Fix

Added the same shallow detection before the update fetch, and append depth_args to the fetch command. When the repo is shallow, --depth 1 is passed to preserve the boundary. When not shallow, no args are added (full fetch is fine).

Changes

• hermes_cli/update_cmd.py: Add is_shallow detection and depth_args before the update fetch

Fixes #80049

[teknium1]

Thanks @JonthanaHanh — the "Found 9980 new commit(s)" symptom on issue #80049 is fixed on main by PR #86318, which makes the apply path treat the shallow-boundary count as unknown and recover the real number via the GitHub compare API (hermes_cli/update_cmd.py, tests/hermes_cli/test_update_apply_shallow_count.py), rather than adding --depth 1 to the apply fetch. Closing as implemented-on-main — thanks for pinpointing the check-vs-apply asymmetry, which is exactly what the landed fix addresses.