Add TaskStep.vars to PipelineYamlSchema

See: https://github.com/spring-projects/sts4/issues/307

headless-services/concourse-language-server/src/main/java/org/springframework/ide/vscode/concourse/PipelineYmlSchema.java

@@ -354,10 +354,12 @@ public class PipelineYmlSchema implements YamlSchema {
 		addProp(taskStep, "config", task);
 		addProp(taskStep, "privileged", t_boolean);
 		addProp(taskStep, "params", t_params);
+		addProp(taskStep, "vars", t_params);
 		addProp(taskStep, "image", t_resource_name);
 		addProp(taskStep, "input_mapping",  f.ymap(t_ne_string, t_maybe_resource_name));
 		addProp(taskStep, "output_mapping", t_string_params);
 		taskStep.requireOneOf("config", "file");
+		taskStep.require(Constraints.implies("vars", "file"));
 
 		YBeanType aggregateStep = f.ybean("AggregateStep");
 		YBeanType doStep = f.ybean("DoStep");

headless-services/concourse-language-server/src/main/resources/desc/TaskStep/vars.md

@@ -0,0 +1,34 @@
+*Optional*. A map of template variables to pass to an external task. Only works with external tasks defined in [`file`](https://concourse-ci.org/task-step.html#task-step-file).
+
+This is often used in combination with [`((vars))`](https://concourse-ci.org/setting-pipelines.html#pipeline-vars) in the pipeline.
+
+For example:
+
+```
+plan:
+- get: my-repo
+- task: integration
+  file: my-repo/ci/task.yml
+  vars:
+    text: ((text))
+```
+
+And `task.yml`:
+
+```
+---
+platform: linux
+
+image_resource:
+  type: docker-image
+  source:
+    repository: my.local.registry:8080/my/image
+    username: ((myuser))
+    password: ((mypass))
+
+run:
+  path: echo
+  args: ["((text))"]
+```
+
+This will resolve `"((text))"` to `"Hello World!"`, while `((myuser))` and `((mypass))` will be resolved at runtime via a [credential manager](https://concourse-ci.org/creds.html), if it has been configured.

headless-services/concourse-language-server/src/test/java/org/springframework/ide/vscode/concourse/ConcourseEditorTest.java

@@ -465,7 +465,9 @@ public class ConcourseEditorTest {
 				"    image: some-image\n" +
 				"    params:\n" +
 				"      map: of-stuff\n" +
-				"    input_mapping:\n" +
+				"    vars:\n" +
+				"      map: of-stuff\n" +
+ 				"    input_mapping:\n" +
 				"      map: of-stuff\n" +
 				"    output_mapping:\n" +
 				"      map: of-stuff\n" +
@@ -484,12 +486,43 @@ public class ConcourseEditorTest {
 		editor.assertHoverContains("privileged", "If set to `true`, the task will run with full capabilities");
 		editor.assertHoverContains("image", "Names an artifact source within the plan");
 		editor.assertHoverContains("params", "A map of task parameters to set, overriding those configured in `config` or `file`");
+		editor.assertHoverContains("vars", "A map of template variables to pass to an external task");
 		editor.assertHoverContains("input_mapping", "A map from task input names to concrete names in the build plan");
 		editor.assertHoverContains("output_mapping", "A map from task output names to concrete names");
 		editor.assertHoverContains("config", "Use `config` to inline the task config");
 		editor.assertHoverContains("tags", "Any step can be directed at a pool of workers");
 		editor.assertHoverContains("timeout", "amount of time to limit the step's execution");
 	}
+	
+	@Test
+	public void taskVarsReconcile() throws Exception {
+		Editor editor;
+		
+		editor = harness.newEditor(
+				"jobs:\n" +
+				"- name: some-job-with-external-task\n" +
+				"  plan:\n" +
+				"  - task: do-something\n" +
+				"    file: some-file.yml\n" +
+				"    vars:\n" +
+				"      foo: bar\n"
+		);
+		editor.assertProblems(/*NONE*/);
+		
+		editor = harness.newEditor(
+				"jobs:\n" +
+				"- name: some-job-internal-task\n" +
+				"  plan:\n" +
+				"  - task: do-something\n" +
+				"    config: some-config\n" +
+				"    vars: not-a-map"
+		);
+		editor.assertProblems(
+				"some-config|Expecting a 'Map'",
+				"vars|assumes that 'file' is also defined",
+				"not-a-map|Expecting a 'Map'"
+		);
+	}
 
 	@Test
 	public void aggregateStepHovers() throws Exception {
@@ -3734,6 +3767,7 @@ public class ConcourseEditorTest {
 				"→ privileged",
 				"→ tags",
 				"→ timeout",
+				"→ vars",
 				//Completions with '-'
 				"- aggregate",
 				"- do",