Allow specifying additional WiX compiler options

packages/app-builder-lib/scheme.json

@@ -3388,6 +3388,13 @@
           "default": true,
           "description": "If `warningsAsErrors` is `true` (default): treat warnings as errors. If `warningsAsErrors` is `false`: allow warnings.",
           "type": "boolean"
+        },
+        "additionalWixArgs": {
+          "description": "Any additional arguments to be passed to the WiX installer compiler, such as `[\"-ext\", \"WixUtilExtension\"]`",
+          "type": [
+            "null",
+            "array"
+          ]
         }
       },
       "type": "object"

packages/app-builder-lib/src/options/MsiOptions.ts

@@ -18,4 +18,9 @@ export interface MsiOptions extends CommonWindowsInstallerConfiguration, TargetS
    * @default true
    */
   readonly warningsAsErrors?: boolean
+
+  /**
+   * Any additional arguments to be passed to the WiX installer compiler, such as `["-ext", "WixUtilExtension"]`
+   */
+  readonly additionalWixArgs?: Array<string> | null
 }

packages/app-builder-lib/src/targets/MsiTarget.ts

@@ -138,6 +138,9 @@ export default class MsiTarget extends Target {
     if (this.options.warningsAsErrors !== false) {
       args.push("-wx")
     }
+    if (this.options.additionalWixArgs != null) {
+      args.push(...this.options.additionalWixArgs)
+    }
     return args
   }
 

test/src/windows/msiTest.ts

@@ -1,5 +1,6 @@
 import { app } from "../helpers/packTester"
 import { Platform } from "electron-builder"
+import fs from "fs"
 
 test.ifAll.ifDevOrWinCi(
   "msi",
@@ -62,6 +63,45 @@ test.ifAll.ifDevOrWinCi(
   )
 )
 
+const wixArgsProductName = "Test WiX Args";
+test.ifAll.ifDevOrWinCi(
+  "wix args",
+  app(
+    {
+      targets: Platform.WINDOWS.createTarget("msi"),
+      config: {
+        appId: "build.electron.test.msi.oneClick.wixArgs",
+        extraMetadata: {
+          // version: "1.0.0",
+        },
+        productName: wixArgsProductName,
+        // Inject a custom-action which requires the WixUtilExtension DLL
+        msiProjectCreated: async (path) => {
+          await fs.promises.writeFile(path, (await fs.promises.readFile(path, "utf8")).replace(
+            '</Product>',
+            `<util:CloseApplication xmlns:util="http://wixtoolset.org/schemas/v4/wxs/util"
+              PromptToContinue="no"
+              Target="${wixArgsProductName}.exe"
+              CloseMessage="yes"
+              Timeout="2"
+              TerminateProcess="1"
+              RebootPrompt="no"
+            />
+            </Product>`
+          ));
+        },
+        msi: {
+          // Apply the needed DLL
+          additionalWixArgs: ["-ext", "WixUtilExtension"],
+        },
+      },
+    },
+    {
+      // signed: true,
+    }
+  )
+)
+
 test.skip.ifAll(
   "assisted",
   app({