fix: support asar in package.json's main property even when not kaging to asar during the build

src/platformPackager.ts

@@ -365,12 +365,27 @@ export abstract class PlatformPackager<DC extends PlatformSpecificBuildOptions>
       await checkFileInArchive(path.join(resourcesDir, "app.asar"), relativeFile, messagePrefix)
     }
     else {
-      const outStat = await statOrNull(path.join(resourcesDir, "app", relativeFile))
-      if (outStat == null) {
-        throw new Error(`${messagePrefix} "${relativeFile}" does not exist. Seems like a wrong configuration.`)
-      }
-      else if (!outStat.isFile()) {
-        throw new Error(`${messagePrefix} "${relativeFile}" is not a file. Seems like a wrong configuration.`)
+      const pathParsed = path.parse(file)
+      // Even when packaging to asar is disabled, it does not imply that the main file can not be inside an .asar archive.
+      // This may occur when the packaging is done manually before processing with electron-builder.
+      if (pathParsed.dir.includes(".asar")) {
+        // The path needs to be split to the part with an asar archive which acts like a directory and the part with
+        // the path to main file itself. (e.g. path/arch.asar/dir/index.js -> path/arch.asar, dir/index.js)
+        const pathSplit: Array<string> = pathParsed.dir.split(path.sep)
+        let partWithAsarIndex = 0
+        pathSplit.some((pathPart: string, index: number) => (partWithAsarIndex = index, pathPart.endsWith(".asar")))
+        const asarPath = path.join.apply(path, pathSplit.slice(0, partWithAsarIndex + 1))
+        let mainPath = (pathSplit.length > partWithAsarIndex + 1) ? path.join.apply(pathSplit.slice(partWithAsarIndex + 1)) : ""
+        mainPath += path.join(mainPath, pathParsed.base)
+        await checkFileInArchive(path.join(resourcesDir, "app", asarPath), mainPath, messagePrefix)
+      } else {
+        const outStat = await statOrNull(path.join(resourcesDir, "app", relativeFile))
+        if (outStat == null) {
+          throw new Error(`${messagePrefix} "${relativeFile}" does not exist. Seems like a wrong configuration.`)
+        }
+        else if (!outStat.isFile()) {
+          throw new Error(`${messagePrefix} "${relativeFile}" is not a file. Seems like a wrong configuration.`)
+        }
       }
     }
   }

test/src/BuildTest.ts

@@ -126,6 +126,19 @@ test("invalid main in the app package.json (no asar)", t => t.throws(assertPack(
   }
 }), `Application entry file "main.js" does not exist. Seems like a wrong configuration.`))
 
+test("invalid main in the app package.json (custom asar)", t => t.throws(assertPack("test-app", allPlatforms(false), {
+  projectDirCreated: projectDir => {
+    return BluebirdPromise.all([
+      modifyPackageJson(projectDir, data => {
+        data.main = "path/app.asar/main.js"
+      }, true),
+      modifyPackageJson(projectDir, data => {
+        data.build.asar = false
+      })
+    ])
+  }
+}), /Application entry file "main.js" in the ("[^"]*") does not exist\. Seems like a wrong configuration\./))
+
 test("main in the app package.json (no asar)", () => assertPack("test-app", allPlatforms(false), {
   projectDirCreated: projectDir => {
     return BluebirdPromise.all([
@@ -140,6 +153,19 @@ test("main in the app package.json (no asar)", () => assertPack("test-app", allP
   }
 }))
 
+test("main in the app package.json (custom asar)", () => assertPack("test-app", allPlatforms(false), {
+  projectDirCreated: projectDir => {
+    return BluebirdPromise.all([
+      modifyPackageJson(projectDir, data => {
+        data.main = "path/app.asar/index.js"
+      }, true),
+      modifyPackageJson(projectDir, data => {
+        data.build.asar = false
+      })
+    ])
+  }
+}))
+
 test("relative index", () => assertPack("test-app", allPlatforms(false), {
   projectDirCreated: projectDir => modifyPackageJson(projectDir, data => {
     data.main = "./index.js"