NSIS should fail installation on Windows < 7

ts/scripts/gen-nsis-script.ts

@@ -0,0 +1,92 @@
+// Copyright 2023 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { createIntl } from '@formatjs/intl';
+import path from 'path';
+import fs from 'fs';
+
+// Note: if this warning appears and build fails:
+//
+// "warning 6040: LangString "MUI_TEXT_INSTALLING_TITLE" is not set in language..."
+//
+// Make sure to sync up the values in `util/nsis` with upstream
+// `app-builder-lib`.
+import { REQUIRED_LANGUAGES, LCID } from '../util/nsis';
+
+console.log('Generating updates NSIS script');
+console.log();
+
+const USED = new Set<number>();
+
+const ROOT_DIR = path.join(__dirname, '..', '..');
+const LOCALES_DIR = path.join(ROOT_DIR, '_locales');
+
+const nsisStrings = new Array<string>();
+for (const lang of REQUIRED_LANGUAGES) {
+  const id = LCID[lang] ?? LCID.en_US;
+  if (USED.has(id)) {
+    continue;
+  }
+  USED.add(id);
+
+  // We use "-" in folder names
+  const folder = lang.replace(/_/g, '-');
+  const fallbacks = [folder, folder.replace(/-.*/g, ''), 'en'];
+  let json: Buffer | undefined;
+  for (const f of fallbacks) {
+    try {
+      json = fs.readFileSync(path.join(LOCALES_DIR, f, 'messages.json'));
+      if (f !== folder) {
+        console.error(`Fallback from ${folder} to ${f}`);
+      }
+      break;
+    } catch {
+      // no-op
+    }
+  }
+  if (!json) {
+    throw new Error(`No messages for ${folder}`);
+  }
+  const { 'icu:UnsupportedOSErrorToast': message } = JSON.parse(
+    json.toString()
+  );
+
+  const intl = createIntl({
+    locale: folder,
+    messages: {
+      message: message.messageformat,
+    },
+  });
+
+  const text = intl.formatMessage({ id: 'message' }, { OS: 'Windows' });
+  nsisStrings.push(`# ${lang}`);
+  nsisStrings.push(
+    `LangString signalMinWinVersionErr ${id} ${JSON.stringify(text)}`
+  );
+}
+
+// See: https://www.electron.build/configuration/nsis.html#custom-nsis-script
+//   for description of what `build/installer.nsh` does.
+fs.writeFileSync(
+  path.join(ROOT_DIR, 'build', 'installer.nsh'),
+  [
+    '# DO NOT EDIT. This is a generated file.',
+    '',
+    '!include WinVer.nsh',
+    '',
+    ...nsisStrings,
+    '',
+    '!macro preInit',
+    // TODO: DESKTOP-5092
+    // See: https://github.com/NSIS-Dev/Documentation/tree/42d8b48c4706b295b68879f7d83bd174c52ac8d7/docs/Includes/WinVer
+    // eslint-disable-next-line no-template-curly-in-string
+    '  ${IfNot} ${AtLeastWin7}',
+    '    MessageBox MB_OK|MB_ICONEXCLAMATION "$(signalMinWinVersionErr)"',
+    '    DetailPrint `Windows version check failed`',
+    '    Abort',
+    // eslint-disable-next-line no-template-curly-in-string
+    '  ${EndIf}',
+    '!macroend',
+    '',
+  ].join('\n')
+);