https://treeherder.mozilla.org/jobs?repo=try&revision=ab3726b0265bde7c129166d03f3cf6df2fdb09f1

This try push has two patches, affecting these files:

mozglue/baseprofiler/core/shared-libraries-macos.cc
tools/profiler/core/shared-libraries-macos.cc
widget/cocoa/nsCocoaWindow.mm

All of these files are only compiled on macOS.

Yet, all jobs on the try push are on Windows, Linux and Android.

I just ran into this again, this time with gfxPlatformMac.cpp. ./mach try auto is currently not usable for Mac-only changes.

The severity field is not set for this bug.
:ahal, could you have a look please?

For more information, please visit auto_nag documentation.

This is a known issue. The test selection is smart, but the ML doesn't factor in platforms at all. So there's a naive heuristic that filters down platforms after the fact. Initially we were planning to support platform in the ML model, but this got dropped after the layoffs. I think there's a bug open for this already, but I'm not finding it atm. I'll leave this open for now, but will dupe if I find the bug.

Bug 1632571 would help a lot, you'd benefit from try auto test selection, but you'd also be able to manually specify the platforms.