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

…ncies. (#5027)

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

@@ -608,9 +608,8 @@ object AppDefinition extends GeneralPurposeCombinators {
     */
   def validAppDefinition(implicit pluginManager: PluginManager): Validator[AppDefinition] =
     validator[AppDefinition] { app =>
-      app.id is valid
-      app.id is PathId.absolutePathValidator
-      app.dependencies is every(PathId.validPathWithBase(app.id.parent))
+      app.id is valid and PathId.absolutePathValidator
+      app.dependencies is valid
     } and validBasicAppDefinition and pluginValidators
 
   /**
@@ -806,4 +805,4 @@ object AppDefinition extends GeneralPurposeCombinators {
       }
     }
   }
-}
+}

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

@@ -0,0 +1,46 @@
+package mesosphere.marathon
+package api.validation
+
+import mesosphere.UnitTest
+import mesosphere.marathon.core.plugin.PluginManager
+import mesosphere.marathon.state.{ AppDefinition, PathId }
+
+class AppDefinitionValidationTest extends UnitTest {
+
+  "AppDefinition" when {
+
+    "created with dependencies" should {
+
+      "be valid with dependencies pointing to a a subtree of this app" in new Fixture {
+        val app = AppDefinition(
+          id = PathId("/a/b/c/d"),
+          cmd = Some("sleep 1000"),
+          dependencies = Set(PathId("/a/b/c/e"))
+        )
+        validator(app).isSuccess shouldBe true
+      }
+
+      "be valid with dependencies pointing to a different subtree (Regression for #5024)" in new Fixture {
+        val app = AppDefinition(
+          id = PathId("/a/b/c/d"),
+          cmd = Some("sleep 1000"),
+          dependencies = Set(PathId("/x/y/z"))
+        )
+        validator(app).isSuccess shouldBe true
+      }
+
+      "be invalid with dependencies with invalid path chars" in new Fixture {
+        val app = AppDefinition(
+          id = PathId("/a/b/c/d"),
+          cmd = Some("sleep 1000"),
+          dependencies = Set(PathId("/a/.../"))
+        )
+        validator(app).isSuccess shouldBe false
+      }
+    }
+  }
+
+  class Fixture {
+    val validator = AppDefinition.validAppDefinition(PluginManager.None)
+  }
+}