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Explicitly set `phabricatorTriggeredBuild` to false on exit points on `AgentBuildExtension` because we are seeing behaviour that suggest the default value is not used in the `sourcesUpdated` step

Teamcity-Phabricator-Plugin/phabricator-plugin-agent/src/main/java/uk/xlab/teamcity/phabricator/AgentBuildExtension.java

@@ -42,6 +42,7 @@ public class AgentBuildExtension extends AgentLifeCycleAdapter {
                 .getBuildFeaturesOfType(Constants.BUILD_FEATURE_TYPE);
 
         if (phabricatorBuildFeatureParameters.isEmpty()) {
+            phabricatorTriggeredBuild = false;
             return;
         }