Fix Fantom getRenderedOutput not reflecting removed props (#55891)

Summary:
Pull Request resolved: #55891

`RenderOutput::renderView` merged old cached props with new debug props
via `mergeDynamicProps`. Since `getDebugProps()` omits default-valued
props, removed props were never cleared from the cache. Also,
`renderedViews_.insert()` never overwrote existing entries.

Changelog: [Internal]

Reviewed By: javache

Differential Revision: D95055704

fbshipit-source-id: 6cdcbde0473a1d03785f49a9eac79be18395a0bf

Author: sammy-SC

packages/react-native/Libraries/Components/View/__tests__/View-itest.js

@@ -670,6 +670,28 @@ describe('<View>', () => {
         );
       });
     });
+
+    describe('nativeID', () => {
+      it('resets nativeID when removed', () => {
+        const root = Fantom.createRoot();
+
+        Fantom.runTask(() => {
+          root.render(<View nativeID="my-id" collapsable={false} />);
+        });
+
+        expect(root.getRenderedOutput({props: ['nativeID']}).toJSX()).toEqual(
+          <rn-view nativeID="my-id" />,
+        );
+
+        Fantom.runTask(() => {
+          root.render(<View collapsable={false} />);
+        });
+
+        expect(root.getRenderedOutput({props: ['nativeID']}).toJSX()).toEqual(
+          <rn-view />,
+        );
+      });
+    });
   });
 
   describe('ref', () => {

private/react-native-fantom/tester/src/render/RenderOutput.cpp

@@ -9,7 +9,6 @@
 #include <react/debug/react_native_assert.h>
 #include <react/renderer/components/text/ParagraphState.h>
 #include <react/renderer/core/ConcreteState.h>
-#include <react/renderer/core/DynamicPropsUtilities.h>
 
 namespace facebook::react {
 
@@ -35,41 +34,18 @@ std::string RenderOutput::render(
     result.push_back(renderView(*child, options));
   }
 
-  // Remove any views from renderedViews_ that are no longer in the tree.
-  for (auto it = renderedViews_.begin(); it != renderedViews_.end();) {
-    if (!tree.hasTag(it->first)) {
-      it = renderedViews_.erase(it);
-    } else {
-      ++it;
-    }
-  }
-
   treesMutated_.erase(tree.getRootStubView().surfaceId);
   return folly::toJson(result);
 }
 
 folly::dynamic RenderOutput::renderView(
     const StubView& view,
     const RenderFormatOptions& options) {
-  if (!treesMutated_.contains(view.surfaceId)) {
-    if (auto it = renderedViews_.find(view.tag); it != renderedViews_.end()) {
-      return it->second;
-    }
-  }
-
   folly::dynamic element = folly::dynamic::object;
   element["type"] = view.componentName;
 
 #if RN_DEBUG_STRING_CONVERTIBLE
-  folly::dynamic props = nullptr;
-  if (auto it = renderedViews_.find(view.tag); it != renderedViews_.end()) {
-    props = mergeDynamicProps(
-        it->second["props"],
-        renderProps(view.props->getDebugProps()),
-        NullValueStrategy::Override);
-  } else {
-    props = renderProps(view.props->getDebugProps());
-  }
+  folly::dynamic props = renderProps(view.props->getDebugProps());
 #else
   folly::dynamic props = folly::dynamic::object;
 #endif
@@ -96,8 +72,6 @@ folly::dynamic RenderOutput::renderView(
 #endif
   element["props"] = props;
 
-  renderedViews_.insert({view.tag, element});
-
   return element;
 }
 

private/react-native-fantom/tester/src/render/RenderOutput.h

@@ -31,8 +31,6 @@ class RenderOutput {
 
   folly::dynamic renderAttributedString(const Tag &selfTag, const AttributedString &string);
 
-  std::unordered_map<Tag, folly::dynamic> renderedViews_{};
-
   // If true, the next call to render() will re-render the entire tree.
   std::unordered_set<SurfaceId> treesMutated_{};
 };