Watcher: Ensure awesome painless exceptions are propagated to the user (elastic/elasticsearch#3707)

When adding a watch which has a painless component, the scriptexception
was wrapped into a deprecated exception which means, that the awesome
painless descriptions were lost. This wrapping has been removed.

Closes elastic/elasticsearch#3161

Original commit: elastic/x-pack-elasticsearch@1703fe4eb6

elasticsearch/src/main/java/org/elasticsearch/xpack/watcher/condition/script/ExecutableScriptCondition.java

@@ -31,13 +31,9 @@ public class ExecutableScriptCondition extends ExecutableCondition<ScriptConditi
     public ExecutableScriptCondition(ScriptCondition condition, Logger logger, ScriptService scriptService) {
         super(condition, logger);
         this.scriptService = scriptService;
-        try {
         Script script = new Script(condition.script.getScript(), condition.script.getType(),
                                    condition.script.getLang(), condition.script.getParams());
         compiledScript = scriptService.compile(script, Watcher.SCRIPT_CONTEXT, Collections.emptyMap());
-        } catch (Exception e) {
-            throw invalidScript("failed to compile script [{}]", e, condition.script, e);
-        }
     }
 
     @Override

elasticsearch/src/test/java/org/elasticsearch/xpack/watcher/condition/script/ScriptConditionTests.java

@@ -171,7 +171,7 @@ public class ScriptConditionTests extends ESTestCase {
         XContentParser parser = XContentFactory.xContent(builder.bytes()).createParser(builder.bytes());
         parser.nextToken();
         ScriptCondition scriptCondition = conditionParser.parseCondition("_watch", parser, false);
-        expectThrows(GeneralScriptException.class,
+        expectThrows(IllegalArgumentException.class,
                 () -> conditionParser.createExecutable(scriptCondition));
     }
 
@@ -182,9 +182,9 @@ public class ScriptConditionTests extends ESTestCase {
         XContentParser parser = XContentFactory.xContent(builder.bytes()).createParser(builder.bytes());
         parser.nextToken();
         ScriptCondition scriptCondition = conditionParser.parseCondition("_watch", parser, false);
-        GeneralScriptException exception = expectThrows(GeneralScriptException.class,
+        IllegalArgumentException exception = expectThrows(IllegalArgumentException.class,
                 () -> conditionParser.createExecutable(scriptCondition));
-        assertThat(exception.getMessage(), containsString("script_lang not supported [not_a_valid_lang]]"));
+        assertThat(exception.getMessage(), containsString("script_lang not supported [not_a_valid_lang]"));
     }
 
     public void testScriptConditionThrowException() throws Exception {

elasticsearch/src/test/java/org/elasticsearch/xpack/watcher/test/integration/HttpSecretsIntegrationTests.java

@@ -8,16 +8,15 @@ package org.elasticsearch.xpack.watcher.test.integration;
 import com.squareup.okhttp.mockwebserver.MockResponse;
 import com.squareup.okhttp.mockwebserver.MockWebServer;
 import com.squareup.okhttp.mockwebserver.RecordedRequest;
-import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.action.get.GetResponse;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.support.XContentMapValues;
-import org.elasticsearch.xpack.security.crypto.CryptoService;
-import org.elasticsearch.xpack.watcher.client.WatcherClient;
-import org.elasticsearch.xpack.watcher.execution.ActionExecutionMode;
 import org.elasticsearch.xpack.common.http.HttpRequestTemplate;
 import org.elasticsearch.xpack.common.http.auth.basic.ApplicableBasicAuth;
 import org.elasticsearch.xpack.common.http.auth.basic.BasicAuth;
+import org.elasticsearch.xpack.security.crypto.CryptoService;
+import org.elasticsearch.xpack.watcher.client.WatcherClient;
+import org.elasticsearch.xpack.watcher.execution.ActionExecutionMode;
 import org.elasticsearch.xpack.watcher.support.xcontent.XContentSource;
 import org.elasticsearch.xpack.watcher.test.AbstractWatcherIntegrationTestCase;
 import org.elasticsearch.xpack.watcher.transport.actions.execute.ExecuteWatchResponse;
@@ -29,7 +28,6 @@ import org.joda.time.DateTime;
 import org.junit.After;
 import org.junit.Before;
 
-import java.net.BindException;
 import java.util.Map;
 
 import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
@@ -62,16 +60,8 @@ public class HttpSecretsIntegrationTests extends AbstractWatcherIntegrationTestC
 
     @Before
     public void init() throws Exception {
-        for (int webPort = 9200; webPort < 9300; webPort++) {
-            try {
         webServer = new MockWebServer();
-                webServer.start(webPort);
-                return;
-            } catch (BindException be) {
-                logger.warn("port [{}] was already in use trying next port", webPort);
-            }
-        }
-        throw new ElasticsearchException("unable to find open port between 9200 and 9300");
+        webServer.start();
     }
 
     @After

qa/smoke-test-watcher-with-painless/src/test/resources/rest-api-spec/test/watcher_painless/40_exception.yaml

@@ -0,0 +1,36 @@
+---
+"Test awesome painless exceptions are returned including the script_stack field":
+  - do:
+      cluster.health:
+          wait_for_status: green
+
+  - do:
+      catch: request
+      xpack.watcher.put_watch:
+        id: "my_exe_watch"
+        body:  >
+          {
+            "trigger" : {
+              "schedule" : { "cron" : "0 0 0 1 * ? 2099" }
+            },
+            "input" : {
+              "simple" : {}
+            },
+            "condition" : {
+              "script" : {
+                "inline" : "FOO == 1",
+                "lang" : "painless"
+              }
+            },
+            "actions" : {
+              "email_admin" : {
+                "email" : {
+                  "to" : "someone@domain.host.com",
+                  "subject" : "404 recently encountered"
+                }
+              }
+            }
+          }
+
+  - is_true: error.script_stack
+  - match: { status: 500 }