[rd][debugger] IJPL-177087 Don't re-send the very same execution stack

GitOrigin-RevId: 3d16ee3c9fcc4d99ba880b368288f448162035a1

platform/xdebugger-impl/backend/src/com/intellij/platform/debugger/impl/backend/BackendXExecutionStackApi.kt

@@ -48,9 +48,6 @@ internal class BackendXExecutionStackApi : XExecutionStackApi {
         }
       }
 
-      // TODO[IJPL-177087]: executionStackEntity gets removed from DB because new ones come to the flow for some reason,
-      //  so addStackFrames may end abruptly, with not all stack frames shown.
-      //  Investigate whether it's really needed
       withEntities(executionStackEntity) {
         val executionStack = executionStackEntity.obj
         executionStack.computeStackFrames(firstFrameIndex, object : XExecutionStack.XStackFrameContainer {

platform/xdebugger-impl/src/com/intellij/xdebugger/impl/XDebugSessionImpl.kt

@@ -142,6 +142,7 @@ class XDebugSessionImpl @JvmOverloads constructor(
   var currentExecutionStack: XExecutionStack?
     get() = executionStackFlow.value.get()
     private set(value) {
+      if (executionStackFlow.value.get() === value) return
       executionStackFlow.value = Ref.create(value)
     }
   private val suspendContextFlow = MutableStateFlow<XSuspendContext?>(null)