Good point but maybe you can consider only turning on unique script name generation when this flag is present? V8ScriptEngineFlags.EnableDebugging
We'd prefer to keep the unique names for now, as they also show up in script error stack traces, which V8 makes available even when debugging is disabled. With some improvements we're making in the next release, generating a unique name takes approximately 600 nanoseconds on an old Core i7 920 PC; this is unlikely to affect real-world script execution times significantly. Besides, if you're executing a script many times, you can compile it to eliminate the overhead.