API: Equality Operator for StackFrame

[sdimitro]

Two distinct StackFrame objects that seem to have the same fields (but originated from different stack traces) are not equal.

Example:

>>> a
<_drgn.StackFrame object at 0x7fa6551968f0>
>>> a.pc
18446744071656044545
>>> a.symbol()
Symbol(name='__schedule', address=0xffffffff8599f570, size=0x891)
>>> b
<_drgn.StackFrame object at 0x7fa655196b10>
>>> b.pc
18446744071656044545
>>> b.symbol()
Symbol(name='__schedule', address=0xffffffff8599f570, size=0x891)
>>> a.pc == b.pc
True
>>> a.symbol() == b.symbol()
True
>>> a == b
False

[sdimitro]

Per our discussion in the Slack group I'm closing this issue. The points for that decision are highlighted below:

• This whole issue was opened as SDB was researching ways to do stack aggregations (e.g. group threads together if their stack traces look the same)
• Currently, the StackFrame object doesn't have any other fields so an equality operator like that could make sense
• In the future though a StackFrame may have more info like registers, local variables, etc.. that would make the state of those objects more distinct so we probably don't want to implement equality now and get rid of it later
• An idea around that would be to later implement helpers functions for such comparisons (e.g. a StackTrace helper which just checks the if the PCs of each frame in the stack match the frames of a different StackTrace object in thes same order).