fix: accept <source> as <video> child (#5264)

Transparent category was overriden by parent categories without merging
others from current element.

Author: TrySound

apps/builder/app/shared/content-model.test.tsx

@@ -489,6 +489,22 @@ test("edge case: support a > img", () => {
   ).toBeTruthy();
 });
 
+test("support video > source", () => {
+  expect(
+    isTreeSatisfyingContentModel({
+      ...renderData(
+        <ws.element ws:tag="body" ws:id="bodyId">
+          <ws.element ws:tag="video">
+            <ws.element ws:tag="source" />
+          </ws.element>
+        </ws.element>
+      ),
+      metas: defaultMetas,
+      instanceSelector: ["bodyId"],
+    })
+  ).toBeTruthy();
+});
+
 describe("component content model", () => {
   test("restrict children with specific component", () => {
     expect(

apps/builder/app/shared/content-model.ts

@@ -114,7 +114,10 @@ const getElementChildren = (
   let elementChildren: string[] =
     tag === undefined ? ["transparent"] : elementsByTag[tag].children;
   if (elementChildren.includes("transparent") && allowedCategories) {
-    elementChildren = allowedCategories;
+    // merge categories from parent and current element when transparent occured
+    elementChildren = elementChildren.flatMap((category) =>
+      category === "transparent" ? allowedCategories : category
+    );
   }
   // introduce custom non-interactive category to restrict nesting interactive elements
   // like button > button or a > input