Do not drop legacy profile alloc metrics when they are equal to in-use ones #433
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Codecov Report
@@ Coverage Diff @@
## master #433 +/- ##
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+ Coverage 67.09% 67.14% +0.05%
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Files 37 37
Lines 7594 7594
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+ Hits 5095 5099 +4
+ Misses 2096 2093 -3
+ Partials 403 402 -1
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This check can be tracked down to a similar check on the old pprof from gperftools:
https://github.com/gperftools/gperftools/blob/e9ab4c53041ac62feefbbb076d326e9a77dd1567/src/pprof#L4108
It was for dealign with very old profiles on the legacy format. I'm not sure if gperftools is still generating profiles that matches this. If so, that may be a concern as this change would make profiles before and after this change incompatible. Please confirm that before submitting.
The best solution would be to update the profile source to use profile.proto directly, instead of the legacy format.
Fixes #432.
In #432 the user has a number of collected heap profiles in the legacy
format that they ask pprof to merge and open and the merge fails.
The reason for the error is that one of the profiles has the alloc
metric values equal to the in-use ones in the header line. Since pprof
legacy profile parser drops the alloc metrics in this case, the profiles
can't be merged since the merge requires that the sample types are the
same between merged profiles.
This PR makes the parser stop dropping the alloc metrics in this case.
This behavior seems more correct anyway as there doesn't seem to be a
strong reason for such implicit behavior and in case of parsing
profile.proto profiles there isn't such implicit behavior either. But
may be I am missing some history here, so please review.