Bugzilla

I can confirm that this is due to bug 1549482:
- On Mac, stack walking availability is dependent on `MOZ_PROFILING`, which is only defined by default on Nightly (because frame pointers are needed, and are only available on Nightly), hence the resulting issue when moving to beta.
- Some tests only enable the "StackWalk" feature (e.g., Profiler.Markers), which gets effectively disabled because stack walking is not available on beta/Mac.
- Bug 1549482 "cleverly" assumed that no StackWalk/Leaf/Javascript meant the user was not interested in capturing backtraces, in this the misnamed Profiler.Markers test expects to find labels.

It would be possible to just add the "Leaf" feature to force backtraces, but I'm afraid that other tests may also rely on this (e.g., possibly bug 1584976), so I will revert part of bug 1549482, and instead add a new feature -- that was discussed as an alternative anyway, which will be less surprising to tests and people.

I can confirm that this is due to bug 1549482:
- On Mac, stack walking availability is dependent on `MOZ_PROFILING`, which is only defined by default on Nightly (because frame pointers are needed, and are only available on Nightly), hence the resulting issue when moving to beta.
- Some tests only enable the "StackWalk" feature (e.g., Profiler.Markers), which gets effectively disabled because stack walking is not available on beta/Mac.
- Bug 1549482 "cleverly" assumed that no StackWalk/Leaf/Javascript meant the user was not interested in capturing backtraces, in which the misnamed Profiler.Markers test expects to find labels.

It would be possible to just add the "Leaf" feature to force backtraces, but I'm afraid that other tests may also rely on this (e.g., possibly bug 1584976), so I will revert part of bug 1549482, and instead add a new feature -- that was discussed as an alternative anyway, which will be less surprising to tests and people.