Add RuntimeTargetDelegate::serializeStackTrace API

Summary:
Changelog: [Internal]

Adds an engine-agnostic mechanism for serialising a previously captured stack trace as a CDP [`Runtime.StackTrace`](https://cdpstatus.reactnative.dev/devtools-protocol/tot/Runtime#type-StackTrace). This complements the existing `RuntimeTargetDelegate::captureStackTrace` method, which returns an opaque, engine-specific representation of a stack trace.

This can be used as a building block for implementing higher-level CDP message types like [`Network.Initiator`](https://cdpstatus.reactnative.dev/devtools-protocol/tot/Network#type-Initiator) within React Native, while keeping the underlying stack trace representation private to each engine.

Differential Revision: D83754142

Author: motiz88

packages/react-native/ReactCommon/hermes/inspector-modern/chrome/HermesRuntimeTargetDelegate.cpp

@@ -62,6 +62,7 @@ class HermesRuntimeSamplingProfileDelegate {
 } // namespace
 
 #ifdef HERMES_ENABLE_DEBUGGER
+
 class HermesRuntimeTargetDelegate::Impl final : public RuntimeTargetDelegate {
   using HermesStackTrace = debugger::StackTrace;
 
@@ -78,6 +79,14 @@ class HermesRuntimeTargetDelegate::Impl final : public RuntimeTargetDelegate {
       return &hermesStackTrace_;
     }
 
+    const HermesStackTrace& operator*() const {
+      return hermesStackTrace_;
+    }
+
+    const HermesStackTrace* operator->() const {
+      return &hermesStackTrace_;
+    }
+
    private:
     HermesStackTrace hermesStackTrace_;
   };
@@ -216,6 +225,16 @@ class HermesRuntimeTargetDelegate::Impl final : public RuntimeTargetDelegate {
     return samplingProfileDelegate_->collectSamplingProfile();
   }
 
+  std::optional<folly::dynamic> serializeStackTrace(
+      const StackTrace& stackTrace) override {
+    if (auto* hermesStackTraceWrapper =
+            dynamic_cast<const HermesStackTraceWrapper*>(&stackTrace)) {
+      return folly::parseJson(cdpDebugAPI_->serializeStackTraceToJsonStr(
+          **hermesStackTraceWrapper));
+    }
+    return std::nullopt;
+  }
+
  private:
   HermesRuntimeTargetDelegate& delegate_;
   std::shared_ptr<HermesRuntime> runtime_;
@@ -311,6 +330,11 @@ HermesRuntimeTargetDelegate::collectSamplingProfile() {
   return impl_->collectSamplingProfile();
 }
 
+std::optional<folly::dynamic> HermesRuntimeTargetDelegate::serializeStackTrace(
+    const StackTrace& stackTrace) {
+  return impl_->serializeStackTrace(stackTrace);
+}
+
 #ifdef HERMES_ENABLE_DEBUGGER
 CDPDebugAPI& HermesRuntimeTargetDelegate::getCDPDebugAPI() {
   return impl_->getCDPDebugAPI();

packages/react-native/ReactCommon/hermes/inspector-modern/chrome/HermesRuntimeTargetDelegate.h

@@ -60,6 +60,9 @@ class HermesRuntimeTargetDelegate : public RuntimeTargetDelegate {
 
   tracing::RuntimeSamplingProfile collectSamplingProfile() override;
 
+  std::optional<folly::dynamic> serializeStackTrace(
+      const StackTrace& stackTrace) override;
+
  private:
   // We use the private implementation idiom to ensure this class has the same
   // layout regardless of whether HERMES_ENABLE_DEBUGGER is defined. The net

packages/react-native/ReactCommon/jsinspector-modern/FallbackRuntimeTargetDelegate.cpp

@@ -58,4 +58,10 @@ FallbackRuntimeTargetDelegate::collectSamplingProfile() {
       "Sampling Profiler capabilities are not supported for Runtime fallback");
 }
 
+std::optional<folly::dynamic>
+FallbackRuntimeTargetDelegate::serializeStackTrace(
+    const StackTrace& stackTrace) {
+  return std::nullopt;
+}
+
 } // namespace facebook::react::jsinspector_modern

packages/react-native/ReactCommon/jsinspector-modern/FallbackRuntimeTargetDelegate.h

@@ -46,6 +46,9 @@ class FallbackRuntimeTargetDelegate : public RuntimeTargetDelegate {
 
   tracing::RuntimeSamplingProfile collectSamplingProfile() override;
 
+  std::optional<folly::dynamic> serializeStackTrace(
+      const StackTrace& stackTrace) override;
+
  private:
   std::string engineDescription_;
 };

packages/react-native/ReactCommon/jsinspector-modern/RuntimeTarget.h

@@ -108,6 +108,14 @@ class RuntimeTargetDelegate {
    * Return recorded sampling profile for the previous sampling session.
    */
   virtual tracing::RuntimeSamplingProfile collectSamplingProfile() = 0;
+
+  /**
+   * \returns a JSON representation of the given stack trace, conforming to the
+   * @cdp Runtime.StackTrace type, if the runtime supports it. Otherwise,
+   * returns std::nullopt.
+   */
+  virtual std::optional<folly::dynamic> serializeStackTrace(
+      const StackTrace& stackTrace) = 0;
 };
 
 /**

packages/react-native/ReactCommon/jsinspector-modern/tests/InspectorMocks.h

@@ -169,6 +169,11 @@ class MockRuntimeTargetDelegate : public RuntimeTargetDelegate {
       collectSamplingProfile,
       (),
       (override));
+  MOCK_METHOD(
+      std::optional<folly::dynamic>,
+      serializeStackTrace,
+      (const StackTrace& stackTrace),
+      (override));
 
   inline MockRuntimeTargetDelegate() {
     using namespace testing;