[Net] Fix IP address resolution incorrectly locking the main thread.

[Faless]

This seems to be a pretty old bug, older then originally reported (at least under certain circumstances).

The IP singleton uses a resolve queue so developers can queue hostnames for resolution in a separate while keeping the main thread unlocked (address-resolution OS functions are blocking, and could block for a long time in case of network disruption).

In most places though, the address resolution function was called with the mutex locked, causing other functions (querying status, queueing another hostname, ecc) to block until that resolution ended.

This commit ensures that all calls to OS address resolution are done with the mutex unlocked.

Fixes #51181 . Note: wile in the issue this is described as a regression, this is a very old issue (according to my tests), according to my tests on Linux, and can be found even to 2.1. I suspect testing it is just tricky due to OS/router DNS caches.

3.x version here

[tavurth]

Wow so fast 🎉

[akien-mga]

Thanks!

[akien-mga]

Cherry-picked for 3.4.

[akien-mga]

Fixes #51181 . Note: wile in the issue this is described as a regression, this is a very old issue (according to my tests), according to my tests on Linux, and can be found even to 2.1. I suspect testing it is just tricky due to OS/router DNS caches.

Isn't this a regression from #49026? If so that would explain why it's present in 2.1, as this change was made in 2.1 and not master until #49026, which was then backported to 3.x.

If so, the 3.3 branch shouldn't be affected (and indeed the fix doesn't seem to cherry-pick cleanly at least).

[Faless]

3.2 seems to also have the underlying bug, though maybe harder to get to (would still break if you had to HTTPRequest at least):

https://github.com/godotengine/godot/blob/3.2/core/io/ip.cpp#L99-L106