Fix Linux build and packaging for Node.js v22

README.md

@@ -5,3 +5,48 @@ A Commodore 64 PETSCII graphics editor written in React/Redux/Electron.
 Documentation & downloads: [https://nurpax.github.io/petmate/](https://nurpax.github.io/petmate/)
 
 The rest of this document is intended for Petmate developers.
+
+## Building and running on Linux
+
+These instructions assume Node.js v18+ and npm. `yarn` is not required.
+
+### System dependencies
+
+Building a `.deb` package requires `fakeroot` and `dpkg-dev`:
+
+```bash
+sudo apt install fakeroot dpkg-dev
+```
+
+### Install Node dependencies
+
+```bash
+npm install
+```
+
+### Run in development mode
+
+```bash
+npm start
+```
+
+This starts the React dev server and launches Electron pointing at it.
+
+> **Note:** The `start` script sets `NODE_OPTIONS=--openssl-legacy-provider` scoped to the React dev server only (required for webpack compatibility with Node.js v17+), and passes `--no-sandbox` to Electron (required on Linux systems where the Chrome sandbox setuid binary is not configured).
+
+### Package as a .deb
+
+First build the production React bundle, then run electron-builder:
+
+```bash
+npm run build
+npm run dist-linux
+```
+
+This produces a `.deb` package at `dist/petmate_<version>_amd64.deb`.
+
+To install it:
+
+```bash
+sudo apt install ./dist/petmate_*_amd64.deb
+```

build-scripts/afterInstall.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+# Post-install script: replace the /usr/bin/petmate symlink with a wrapper
+# that passes --no-sandbox to Electron (required on systems where the Chrome
+# sandbox setuid binary is not configured).
+
+set -euo pipefail
+
+WRAPPER=/usr/bin/petmate
+BINARY=/opt/Petmate/petmate
+
+# Remove the symlink (or existing file) created by the deb package
+rm -f "$WRAPPER"
+
+# Write a small wrapper script in its place
+cat > "$WRAPPER" <<'EOF'
+#!/bin/sh
+exec /opt/Petmate/petmate --no-sandbox "$@"
+EOF
+
+chmod 755 "$WRAPPER"