Handle jar signer errors.

src/main/kotlin/com/beust/kobalt/misc/RunCommand.kt

@@ -23,6 +23,7 @@ open class RunCommand(val command: String) {
      * This field is used to specify how errors are caught.
      */
     var useErrorStreamAsErrorIndicator = true
+    var useInputStreamAsErrorIndicator = false
 
     fun useErrorStreamAsErrorIndicator(f: Boolean) : RunCommand {
         useErrorStreamAsErrorIndicator = f
@@ -52,6 +53,9 @@ open class RunCommand(val command: String) {
         if (useErrorStreamAsErrorIndicator && ! hasErrors) {
             hasErrors = hasErrors || hasErrorStream
         }
+        if (useInputStreamAsErrorIndicator && ! hasErrors) {
+            hasErrors = hasErrors || process.inputStream.available() > 0
+        }
 
         if (! hasErrors) {
             successCallback(fromStream(process.inputStream))

src/main/kotlin/com/beust/kobalt/plugin/android/AndroidPlugin.kt

@@ -308,17 +308,19 @@ public class AndroidPlugin @Inject constructor(val javaCompiler: JavaCompiler, v
             throw KobaltException("No signingConfig found for product type $buildType")
         }
 
-        val success = RunCommand("jarsigner").run(listOf(
+        val success = RunCommand("jarsigner").apply {
+//            useInputStreamAsErrorIndicator = true
+        }.run(listOf(
                 "-keystore", signingConfig.storeFile,
                 "-storepass", signingConfig.storePassword,
                 "-keypass", signingConfig.keyPassword,
                 "-signedjar", apk,
                 temporaryApk,
                 signingConfig.keyAlias
-        ))
-        log(1, "Created $apk")
+            ))
+            log(1, "Created $apk")
 
-        return TaskResult(success == 0)
+            return TaskResult(success == 0)
     }
 
     @Task(name = "install", description = "Install the apk file", runAfter = arrayOf(TASK_GENERATE_DEX, "assemble"))