Change isolate trace field from number to string

Connor Clark · V8 LUCI CQ · commit b2d2ce2200cc · 2025-09-29T09:19:43.000-07:00
`IsolateId()` is a uint64_t, which cannot convert to JS without precision loss. Beyond that, the way v8 serializes large uint64_t values seems to differ from how blink does, which results in the same isolate presenting as different values. That made it impossible to properly correlate these events for the same isolate. See associated bug for more. Bug: 447654178 Change-Id: I070a2a5532be63a6c77f237d8c96307970058132 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/6991617 Reviewed-by: Michael Lippautz <mlippautz@chromium.org> Commit-Queue: Michael Lippautz <mlippautz@chromium.org> Auto-Submit: Connor Clark <cjamcl@chromium.org> Reviewed-by: Yang Guo <yangguo@chromium.org> Cr-Commit-Position: refs/heads/main@{#102832}
diff --git a/src/objects/script.cc b/src/objects/script.cc
@@ -189,7 +189,7 @@ void Script::TraceScriptRundown() {
   auto value = v8::tracing::TracedValue::Create();
   value->SetInteger("scriptId", this->id());
   value->SetInteger("executionContextId", contextId);
-  value->SetUnsignedInteger("isolate", isolate->debug()->IsolateId());
+  value->SetString("isolate", std::to_string(isolate->debug()->IsolateId()));
   value->SetBoolean("isModule", this->origin_options().IsModule());
   value->SetBoolean("hasSourceUrl", this->HasSourceURLComment());
   if (this->HasValidSource()) {
@@ -231,7 +231,7 @@ void Script::TraceScriptRundownSources() {
   const int32_t kSplitMaxLength = 1000000;    // 1mb
   if (source_length > kSourceMaxLength) {
     auto value = v8::tracing::TracedValue::Create();
-    value->SetUnsignedInteger("isolate", isolate->debug()->IsolateId());
+    value->SetString("isolate", std::to_string(isolate->debug()->IsolateId()));
     value->SetInteger("scriptId", script_id);
     value->SetInteger("length", source_length);
     value->SetInteger("limit", kSourceMaxLength);
@@ -240,7 +240,7 @@ void Script::TraceScriptRundownSources() {
         "TooLargeScriptCatchup", "data", std::move(value));
   } else if (source_length <= kSplitMaxLength) {
     auto value = v8::tracing::TracedValue::Create();
-    value->SetUnsignedInteger("isolate", isolate->debug()->IsolateId());
+    value->SetString("isolate", std::to_string(isolate->debug()->IsolateId()));
     value->SetInteger("scriptId", script_id);
     value->SetInteger("length", source_length);
     value->SetString("sourceText", source->ToCString().get());
@@ -256,8 +256,8 @@ void Script::TraceScriptRundownSources() {
       auto split_trace_value = v8::tracing::TracedValue::Create();
       split_trace_value->SetInteger("splitIndex", i);
       split_trace_value->SetInteger("splitCount", split_count);
-      split_trace_value->SetUnsignedInteger("isolate",
-                                            isolate->debug()->IsolateId());
+      split_trace_value->SetString(
+          "isolate", std::to_string(isolate->debug()->IsolateId()));
       split_trace_value->SetInteger("scriptId", script_id);
       split_trace_value->SetString(
           "sourceText", std::string(source_ptr.get() + begin, end - begin));
