cli: add --trace-uncaught flag

Add a flag that makes Node.js print the stack trace at the
time of *throwing* uncaught exceptions, rather than at the
creation of the `Error` object, if there is any.

This is disabled by default because it affects GC behavior.

PR-URL: https://github.com/nodejs/node/pull/30025
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/src/node_errors.cc b/src/node_errors.cc
index d3a409b1ab4..ec14746514e 100644
--- a/src/node_errors.cc
+++ b/src/node_errors.cc
@@ -380,6 +380,19 @@ static void ReportFatalException(Environment* env,
             "%s\n%s: %s\n", *arrow_string, *name_string, *message_string);
       }
     }
+
+    if (!env->options()->trace_uncaught) {
+      PrintErrorString("(Use `node --trace-uncaught ...` to show "
+                       "where the exception was thrown)\n");
+    }
+  }
+
+  if (env->options()->trace_uncaught) {
+    Local<StackTrace> trace = message->GetStackTrace();
+    if (!trace.IsEmpty()) {
+      PrintErrorString("Thrown at:\n");
+      PrintStackTrace(env->isolate(), trace);
+    }
   }
 
   fflush(stderr);