Artificially set a VERSION environment variable during build steps (#…

…19518)

Fixes #19485

The variable should be set when it needs to by CI, but in every other environment it's not important. Simply setting it to *something* makes EnvironmentPlugin happy. We print a warning just in case people expect it to be set, and use a clear value in case the environment variable doesn't get properly set.

webpack.config.js

@@ -15,6 +15,11 @@ dotenv.config();
 let ogImageUrl = process.env.RIOT_OG_IMAGE_URL;
 if (!ogImageUrl) ogImageUrl = 'https://app.element.io/themes/element/img/logos/opengraph.png';
 
+if (!process.env.VERSION) {
+    console.warn("Unset VERSION variable - this may affect build output");
+    process.env.VERSION = "!!UNSET!!";
+}
+
 const cssThemes = {
     // CSS themes
     "theme-legacy-light": "./node_modules/matrix-react-sdk/res/themes/legacy-light/css/legacy-light.scss",