Force major version number to be present

packages/app-builder-lib/src/appInfo.ts

@@ -77,13 +77,17 @@ export class AppInfo {
 
   getVersionInWeirdWindowsForm(isSetBuildNumber = true): string {
     let [major, minor, patch] = this.version.split('.').map((versionPart) => parseInt(versionPart))
-    // Allow missing version parts. Version '1.2' gets a patch version of 0
-    major ??= 0
+    // The major component must be present. Here it can be either NaN or undefined, which
+    // both returns true from isNaN.
+    if (isNaN(major)) {
+      throw new Error(`Invalid major number in: ${this.version}`)
+    }
+    // Allow missing version parts. Minor and patch can be left out and default to zero
     minor ??= 0
     patch ??= 0
     // ... but reject non-integer version parts. '1.a' is not going to fly
-    if (isNaN(major) || isNaN(minor) || isNaN(patch)) {
-      throw new Error(`Invalid version: ${this.version}`)
+    if (isNaN(minor) || isNaN(patch)) {
+      throw new Error(`Invalid minor or patch number in: ${this.version}`)
     }
     // https://github.com/electron-userland/electron-builder/issues/2635#issuecomment-371792272
     let buildNumber = isSetBuildNumber ? this.buildNumber : null