Make warn message debug so the spam will stop

[jlack1987]

Fixes #358. Change a Warn message to Debug so the spam will stop. Imo opinion this is probably not the best way to fix this, bc as a third party user if I set that error_msg pointer to null then i'm telling the code that I don't care about any string data, I just want the bool return and i'll take it from there. This still logs a message but at least it's debug and most users won't see it but developers can still see it if they set the log level to debug. If this is acceptable can we please backport to foxy?

[clalancette]

We've had this conversation a lot; see #472 , #395 , #405 , #396 , #358 .

We've recently merged in #529 ; can you see if that improves the situation for you?

If there is still too much spam, I'm for reducing it, but my comments in #472 (comment) still apply.

[jlack1987]

I don't fully understand what that change does that you linked there. I can't imagine a case though where you couldn't be able to completely suppress console output from canTransform or lookupTransform. From the users standpoint, the thing returns true/false which is all probably 99.9% of callers of this care about. It's all topic based so I can just while(!canTransform) and wait for it to become available and if it doesn't then false tells me it didn't show up so a user gets to decide how they want to handle that. The only use case for any console output here is for debugging if there's a problem in which case the 3rd party user shouldn't be concerned about that and the user shouldn't have to take any additional action to prevent spam. I think it's even worse though bc, at least in my experience, I can't debug my code with this stuff in there bc the spam from this function prevents me from seeing any console output messages from the code that i'm actually interested in debugging. So me(and everybody else at my company) has to go into our code, find and comment out nodes that use canTransform or lookupTransform so when we run our stack we have a chance to see our console output. Feel free to close.