Concourse: support for ensure attribute

vscode-extensions/vscode-concourse/src/main/java/org/springframework/ide/vscode/concourse/PipelineYmlSchema.java

@@ -133,6 +133,7 @@ public class PipelineYmlSchema implements YamlSchema {
 		// shared properties applicable for any type of Step:
 		prop(step, "on_success", step);
 		prop(step, "on_failure", step);
+		prop(step, "ensure", step);
 		prop(step, "attempts", t_strictly_pos_integer);
 		
 		YBeanType resource = f.ybean("Resource");

vscode-extensions/vscode-concourse/src/main/resources/desc/Step/attempts.md

@@ -1,4 +1,4 @@
-Retry a step:
+Retry a step.
 
 Any step can set the number of times it should be attempted by attaching an `attempts` parameter with the number of times it should be tried.
 

vscode-extensions/vscode-concourse/src/main/resources/desc/Step/ensure.md

@@ -0,0 +1,22 @@
+Guarantee execution of a step.
+
+Any step can have `ensure` tacked onto it, whose value is a second step to execute regardless of the result of the parent step.
+
+	ensure: step
+
+The step to execute. Regardless of whether the parent step succeeds, fails, or errors, this step will be executed. The step will also be executed if the build was aborted, and its parent step was interrupted.
+
+If the parent step succeeds and the ensured step fails, the parent step is considered to have failed.
+
+The ensured step executes after any `on_success` or `on_failure` hooks.
+
+For example, the following build plan acquires a lock, and then ensures that the lock is released.
+
+	plan:
+	- put: some-lock
+	  params: acquire: true
+	- task: integration
+	  file: foo/integration.yml
+	  ensure:
+	    put: some-lock
+	    params: release: some-lock

vscode-extensions/vscode-concourse/src/test/java/org/springframework/ide/vscode/concourse/PipelineYamlEditorTest.java

@@ -186,7 +186,9 @@ public class PipelineYamlEditorTest {
 				"    on_failure:\n" +
 				"    - bogus: bad\n" +
 				"    on_success:\n" +
-				"    - bogus: bad\n"
+				"    - bogus: bad\n" +
+				"    ensure:\n" +
+				"      task: cleanups\n"
 		);
 		editor.assertHoverContains("resource", "The resource to fetch");
 		editor.assertHoverContains("version", "The version of the resource to fetch");
@@ -195,6 +197,7 @@ public class PipelineYamlEditorTest {
 		editor.assertHoverContains("attempts", "Any step can set the number of times it should be attempted");
 		editor.assertHoverContains("on_failure", "Any step can have `on_failure` tacked onto it");
 		editor.assertHoverContains("on_success", "Any step can have `on_success` tacked onto it");
+		editor.assertHoverContains("ensure", "a second step to execute regardless of the result of the parent step");
 	}
 	
 	@Test