Previously, if there were ignored frames (iseq without pc), we could
go beyond the requested start frame. This has two changes:
Ensure that we don't look beyond the start frame by using
last_cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(last_cfp) until the
desired start frame is reached.
To fix the failures caused by change 1), which occur when a
limited number of frames is requested, scan the VM stack before
allocating backtrace frames, looking for ignored frames. This
is complicated if there are ignored frames before and after
the start, in which case we need to scan until the start frame,
and then scan backwards, decrementing the start value until we
get to the point where start will result in the number of
requested frames.
This fixes a Rails test failure. Jean Boussier was able to
to produce a failing test case outside of Rails.
Added by jeremyevans (Jeremy Evans) over 4 years ago
Ensure that caller respects the start argument
Previously, if there were ignored frames (iseq without pc), we could
go beyond the requested start frame. This has two changes:
Ensure that we don't look beyond the start frame by using
last_cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(last_cfp) until the
desired start frame is reached.
To fix the failures caused by change 1), which occur when a
limited number of frames is requested, scan the VM stack before
allocating backtrace frames, looking for ignored frames. This
is complicated if there are ignored frames before and after
the start, in which case we need to scan until the start frame,
and then scan backwards, decrementing the start value until we
get to the point where start will result in the number of
requested frames.
This fixes a Rails test failure. Jean Boussier was able to
to produce a failing test case outside of Rails.
Co-authored-by: Jean Boussier [email protected]