From db00af180fb2a68bbbf5dc44849f0aeeba296471 Mon Sep 17 00:00:00 2001
From: "Christian Holler (:decoder)" <choller@mozilla.com>
Date: Tue, 28 Nov 2023 11:16:08 +0000
Subject: [PATCH] Bug 1866421 - Make Nyx::is_replay work before snapshot point.
 r=truber

Differential Revision: https://phabricator.services.mozilla.com/D194643
---
 tools/fuzzing/ipc/IPCFuzzController.cpp | 4 ++++
 tools/fuzzing/nyx/Nyx.cpp               | 9 ++++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/tools/fuzzing/ipc/IPCFuzzController.cpp b/tools/fuzzing/ipc/IPCFuzzController.cpp
index e3e7c30654da..06f2fc3b3789 100644
--- a/tools/fuzzing/ipc/IPCFuzzController.cpp
+++ b/tools/fuzzing/ipc/IPCFuzzController.cpp
@@ -1088,6 +1088,10 @@ void IPCFuzzController::SynchronizeOnMessageExecution(
 
 static void dumpIPCMessageToFile(const UniquePtr<IPC::Message>& aMsg,
                                  uint32_t aDumpCount, bool aUseNyx = false) {
+  if (Nyx::instance().is_replay()) {
+    return;
+  }
+
   std::stringstream dumpFilename;
   std::string msgName(IPC::StringFromIPCMessageType(aMsg->type()));
   std::replace(msgName.begin(), msgName.end(), ':', '_');
diff --git a/tools/fuzzing/nyx/Nyx.cpp b/tools/fuzzing/nyx/Nyx.cpp
index 5ef48301e00b..3fbb520b11eb 100644
--- a/tools/fuzzing/nyx/Nyx.cpp
+++ b/tools/fuzzing/nyx/Nyx.cpp
@@ -19,7 +19,12 @@
 namespace mozilla {
 namespace fuzzing {
 
-Nyx::Nyx() {}
+Nyx::Nyx() {
+  char* testFilePtr = getenv("MOZ_FUZZ_TESTFILE");
+  if (testFilePtr) {
+    mReplayMode = true;
+  }
+}
 
 // static
 Nyx& Nyx::instance() {
@@ -63,8 +68,6 @@ void Nyx::start(void) {
   // Check if we are in replay mode.
   char* testFilePtr = getenv("MOZ_FUZZ_TESTFILE");
   if (testFilePtr) {
-    mReplayMode = true;
-
     MOZ_FUZZING_NYX_PRINT("[Replay Mode] Reading data file...\n");
 
     std::string testFile(testFilePtr);