NullPointerException in TransactionExceptionHandler

[cmaan]

Starting with google-cloud-datastore:1.2.1, a user exception thrown within a datastore transaction (runInTransaction) triggers a NullPointerException in com.google.cloud.datastore.TransactionExceptionHandler. The original exception is swallowed.

For reference, a minimal build.gradle which triggers the problem on gradle run is:

import com.google.cloud.datastore.DatastoreOptions;

buildscript {
	repositories {
 mavenCentral()
 maven {
 	url "https://jitpack.io"
 }
 }
	dependencies {
 //classpath "com.google.cloud:google-cloud-datastore:1.2.0" // works
 classpath "com.google.cloud:google-cloud-datastore:1.2.1" // breaks
 //classpath "com.google.cloud:google-cloud-datastore:1.2.2" // breaks
 //classpath "com.github.GoogleCloudPlatform.google-cloud-java:google-cloud-datastore:95f0dd7eb3b7b360ce51b1930c1f75cc2bb91140" // breaks
 }
}

task run() {
	def ds = DatastoreOptions.newBuilder()
 .build()
 .getService();
 ds.runInTransaction({ rw ->
 throw new RuntimeException("foobar");
 });
}

[neozwu]

fixed in #2256