The POSIX sibling of windows-desktop-gui-e2e.ps1, sharing its staging
trick: bare-clone the checkout to serve.git, park main at OLD, point
every git process at it with url.<file://serve.git>.insteadOf in a
driver-owned GIT_CONFIG_GLOBAL. The installer and updater run
byte-for-byte against their real URLs; no bwrap, no MITM proxy, no
TLS interception - a disposable CI runner IS the sandbox, so the
same driver can run on macos-latest unchanged.
install.sh is not curl'd: the install leg runs the copy shipped AT
the OLD ref (what a user who installed then actually executed), the
installer-script update leg runs HEAD's copy (what the website
serves at update time). Flags are probed per-ref (--skip-browser is
newer than sampled tags); HOME is isolated because old installers
hardcode ~/.hermes; .skip_upstream_prompt suppresses the updater's
fork prompt on the file:// origin; the dirty-tree guard checks
tracked files only (-uno) since untracked files cannot leak into a
bare clone.
Verified locally end-to-end: v0.20.2 installed via its own
install.sh (uv, managed Python, Node, venv; hermes --version OK),
served main advanced, hermes update landed the checkout on HEAD
with a working hermes. bash -n + shellcheck clean.
ethernet