Fixes #5024 by using the correct validator for validating app depende…

…ncies. (#5026)

src/main/scala/mesosphere/marathon/state/AppDefinition.scala

@@ -571,7 +571,7 @@ object AppDefinition {
   implicit val validAppDefinition: Validator[AppDefinition] = validator[AppDefinition] { app =>
     app.id is valid
     app.id is PathId.absolutePathValidator
-    app.dependencies is every(PathId.validPathWithBase(app.id.parent))
+    app.dependencies is valid
   } and validBasicAppDefinition
 
   /**

src/test/scala/mesosphere/marathon/api/validation/AppDefinitionValidatorTest.scala

@@ -569,6 +569,33 @@ class AppDefinitionValidatorTest extends MarathonSpec with Matchers with GivenWh
     result.isSuccess shouldBe true
   }
 
+  test("valid with dependencies pointing to a a subtree of an app") {
+    val app = AppDefinition(
+      id = PathId("/a/b/c/d"),
+      cmd = Some("sleep 1000"),
+      dependencies = Set(PathId("/a/b/c/e"))
+    )
+    AppDefinition.validAppDefinition(app).isSuccess shouldBe true
+  }
+
+  test("be valid with dependencies pointing to a different subtree (Regression for #5024)") {
+    val app = AppDefinition(
+      id = PathId("/a/b/c/d"),
+      cmd = Some("sleep 1000"),
+      dependencies = Set(PathId("/x/y/z"))
+    )
+    AppDefinition.validAppDefinition(app).isSuccess shouldBe true
+  }
+
+  test("be invalid with dependencies with invalid path chars") {
+    val app = AppDefinition(
+      id = PathId("/a/b/c/d"),
+      cmd = Some("sleep 1000"),
+      dependencies = Set(PathId("/a/.../"))
+    )
+    AppDefinition.validAppDefinition(app).isSuccess shouldBe false
+  }
+
   class Fixture {
     def validDockerContainer: Container = Container(
       `type` = mesos.ContainerInfo.Type.DOCKER,