hermes-agent/apps/desktop/installer
emozilla c8c8c53a0c feat(desktop): NSIS prereq detection page + auto-install via winget
The packaged Windows installer now detects Python 3.11+ and Git for Windows
at install time and offers to install missing prereqs via winget. Mirrors
the prereq logic scripts/install.ps1 already runs for CLI installs, so
desktop installer users get the same out-of-the-box experience as
install.ps1 users.

Why
- Hermes' terminal tool calls bash.exe directly (tools/environments/
  local.py); on Windows that's Git Bash from Git for Windows. Without it,
  the agent fails on the first terminal() call.
- Hermes' Python runtime needs 3.11+. Without it, the desktop bootstrapper
  errors out at venv creation.
- Both gaps surfaced on a fresh Windows 11 VM smoke test: VM had Python
  pre-installed but no Git, so the agent's first terminal call failed
  with "Git Bash isn't installed."
- install.ps1 has had Install-Git + Install-Uv functions for ages. The
  desktop installer was the asymmetric outlier.

How — NSIS prereq page
- New file: apps/desktop/installer/prereq-check.nsh (plugged into
  electron-builder via build.nsis.include)
- Real Wizard page using nsDialogs, inserted via customPageAfterChangeDir
  hook (between the Directory page and InstFiles).
  - Group boxes for Python and Git, each showing detection status.
  - Pre-checked install checkboxes when winget is available.
  - Auto-skips silently if both prereqs are already installed.
  - Falls back to manual download URLs when winget itself is missing.
- Detection:
  - Python: probes `py -3.11`/`-3.12`/`-3.13`/`-3.14` via the Python
    launcher. Microsoft Store "Python stub" (no py.exe) is correctly
    classified as not-installed.
  - Git: `where git`.
  - winget: `where winget` (Win10 1809+ / Win11 with App Installer).
- Install execution (in customInstall macro):
  - Python: nsExec::ExecToLog with `--scope user --silent`. Per-user
    install, no UAC prompt, output streams to install log.
  - Git: ExecShellWait via Windows ShellExecute. Critical because Git
    always installs per-machine and triggers UAC; ShellExecute preserves
    the foreground focus chain across non-elevated → elevated process
    spawns, so UAC actually comes to the foreground. nsExec::ExecToLog
    breaks the chain because winget runs hidden.
  - Both pass `--disable-interactivity --accept-package-agreements
    --accept-source-agreements` to suppress winget's own dialogs.
- Verification: probes Git's standard install locations via FileExists
  rather than `where git`. NSIS's process inherits PATH at startup, so
  a freshly-installed Git won't be visible to `where` until restart.
- Silent installs (/S) skip the prompts; managed deploys handle prereqs
  out-of-band via Group Policy / Intune.

How — Electron-side safety net
- New findGitBash() in main.cjs, parallel to findSystemPython(). Probes
  the same locations as tools/environments/local.py:_find_bash() so a
  positive result here means the agent's terminal tool will work.
- ensureRuntime now throws a clear, actionable error on Windows when Git
  Bash isn't found, matching the existing "Python 3.11+ is required"
  error path.
- Catches users the NSIS page doesn't: .msi installer users (NSIS prereq
  page doesn't run for MSI), `npm run dev` users, manual installers,
  anyone who unchecked the install boxes on the NSIS prereq page.
- All gated on `IS_WINDOWS`; macOS / Linux unaffected.

NSIS build issue (resolved)
- electron-builder defaults to `-WX` (warnings as errors). NSIS optimizer
  emits "warning 6010: function not referenced" for our page functions
  because Page custom directives don't count as references in its
  static-analysis pass. The functions ARE called at runtime when NSIS
  invokes the page; the optimizer just can't see it statically.
- Set `build.nsis.warningsAsErrors=false` in package.json so this
  spurious warning doesn't fail the build. (Documented option from
  electron-builder's nsisOptions.)

Out of scope (filed for future work)
- MSI prereq detection: Windows Installer custom actions are a different
  mechanism. Enterprise deploys typically handle prereqs via GP/Intune.
- Bundle PortableGit + python-build-standalone in extraResources for
  zero-network installs. ~80MB increase.
- Mac / Linux GUI prereq flows (different installer formats; Xcode CLT
  covers most macOS prereqs already; Linux is per-distro hard).

Files
- apps/desktop/installer/prereq-check.nsh   (new, ~290 lines NSIS)
- apps/desktop/package.json                 (build.nsis.include +
                                              warningsAsErrors)
- apps/desktop/electron/main.cjs            (findGitBash + preflight)
- apps/desktop/README.md                    (Runtime prerequisites
                                              section)

Cross-platform impact
- macOS / Linux builds (dist:mac, dist:mac:dmg, dist:mac:zip): nsis
  config is ignored entirely; .nsh is dormant.
- npm run dev: .nsh dormant; main.cjs preflight gated on IS_WINDOWS.
- scripts/install.ps1, scripts/install.sh: no reference to any new
  files; CLI install paths untouched.
- Hermes CLI / dashboard / gateway: no reference; runtime untouched.
- All checks: node --check on main.cjs and test-desktop.mjs pass;
  npm run test:desktop:platforms 4/4 passing; node --test green.

Tested
- npm run dist:win produces signed .exe and .msi without errors.
- Fresh Win11 VM (Python pre-installed, no Git): prereq page renders,
  Python check shows detected, Git checkbox pre-checked. Click Next →
  Git installs via winget with UAC prompt in foreground.
- After install completes, Hermes launches and the agent's terminal
  tool can run bash commands. Verified Git Bash is detected at
  `C:\Program Files\Git\bin\bash.exe` by ensureRuntime's preflight.
2026-05-11 11:13:49 -04:00
..
prereq-check.nsh feat(desktop): NSIS prereq detection page + auto-install via winget 2026-05-11 11:13:49 -04:00