PY-17717 For subdirectory of a Sources Root, cannot Mark Directory As > Sources from right-click context menu

platform/lang-api/src/com/intellij/openapi/module/ModuleType.java

@@ -132,4 +132,8 @@ public abstract class ModuleType<T extends ModuleBuilder> {
   public boolean isSupportedRootType(JpsModuleSourceRootType type) {
     return true;
   }
+
+  public boolean isMarkInnerSupportedFor(JpsModuleSourceRootType type) {
+    return false;
+  }
 }

platform/lang-impl/src/com/intellij/ide/projectView/actions/MarkSourceRootAction.java

@@ -53,8 +53,9 @@ public class MarkSourceRootAction extends MarkRootActionBase {
 
   @Override
   protected boolean isEnabled(@NotNull RootsSelection selection, @NotNull Module module) {
-    if (!ModuleType.get(module).isSupportedRootType(myRootType) || selection.myHaveSelectedFilesUnderSourceRoots
-        || ModuleSourceRootEditHandler.getEditHandler(myRootType) == null) {
+    final ModuleType moduleType = ModuleType.get(module);
+    if (!moduleType.isSupportedRootType(myRootType) || ModuleSourceRootEditHandler.getEditHandler(myRootType) == null
+        || (selection.myHaveSelectedFilesUnderSourceRoots && !moduleType.isMarkInnerSupportedFor(myRootType))) {
       return false;
     }
 

python/src/com/jetbrains/python/PythonModuleTypeBase.java

@@ -23,6 +23,8 @@ import com.intellij.openapi.module.ModuleTypeManager;
 import icons.PythonIcons;
 import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.jps.model.java.JavaSourceRootType;
+import org.jetbrains.jps.model.module.JpsModuleSourceRootType;
 
 import javax.swing.*;
 
@@ -64,4 +66,9 @@ public abstract class PythonModuleTypeBase<T extends ModuleBuilder> extends Modu
   public Icon getNodeIcon(final boolean isOpened) {
     return PythonIcons.Python.PythonClosed;
   }
+
+  @Override
+  public boolean isMarkInnerSupportedFor(JpsModuleSourceRootType type) {
+    return type == JavaSourceRootType.SOURCE;
+  }
 }