Add trace to 'Deprecated' message

[sunny-lan]

Feature request:

When it shows a message like:

node_redis: Deprecated: The HGET command contains a "null" argument.
This is converted to a "null" string now and will return an error from v.3.0 on.
Please handle this in your code to make sure everything works as you intended it to.

It is hard to find where the issue is coming from. It would be useful to have a stack trace generated every time this happens. Especially if the dev has no choice over what redis version is used.

[stockholmux]

This a reasonable request. Could be integrated with RedisClient.prototype.warn as a one-liner by using console.trace. The only trick would be it would only be listed in the terminal, not from someone listening for errors, but that seems like it's ok.

[sunny-lan]

Wouldn't the console.trace have to be put outside of nextTick? I think a sketchy way to do it would be

const trace=new Error(msg);
process.nextTick(function () {
 if(...) {
   self.emit('warning',trace);
 } else {
   console.warn(trace);
 }
});

I can do a PR if thats ok

[stockholmux]

Good point. I think it would still tell you the location but it wouldn't be at the top level of the trace. Need to think on it, but if you have a suggestion, let's hear it.

[ad34]

+1 on this. sometimes it s tricky to find the code leading to this warning.

[1blockologist]

Yes, or a way to disable these deprecation warnings on production, a real crash will produce a stack trace anyway if an upgraded version ever actually comes out!

These messages fill up my server logs!