fuzz: exercise a little more revlog code
Differential Revision: https://phab.mercurial-scm.org/D7032
fuzz: new fuzzer for dirs.c
This found a six-year-old bug immediately, and then I put it through a
few CPU-days of time before sending it.
Differential Revision: https://phab.mercurial-scm.org/D7031
dirs: fix trivial over-read of input data
This code, introduced in
8c0a7eeda06d, was intentionally over-reading
an input string to avoid getting a shared string object for a one-byte
input. Unfortunately with an empty input (like in the case of a fuzzer
getting started) this was a trivial over-read and triggered an
AddressSanitizer failure.
I went out of my way to make sure the code still does the
copy-avoidance tricks. I don't think this change will cost us much
performance since the one-character strings should be cached
aggressively anyway.
Differential Revision: https://phab.mercurial-scm.org/D7030
sidedatacopies: deal with upgrading and downgrading to that format
This is quite useful to test this on real life data.
Differential Revision: https://phab.mercurial-scm.org/D6955
sidedatacopies: move various copies related function to the copies modules
We will need to access these logic form the copies module. So we move them from
their higher level module to the lower level `copies` module. We cannot use them
from their top level module as it would create cycles.
Differential Revision: https://phab.mercurial-scm.org/D6954
sidedatacopies: read rename information from sidedata
Repository using the new format now use changeset centric algorithm and read the
copies information from the changelog sidedata.
Differential Revision: https://phab.mercurial-scm.org/D6953
changelog: make copies related function return None or a valid value
With the previous code, existing but empty value were not "decoded", leading to
the method returning one of `None`, some valid value (`list` or `dict`) or
`b''`.
On a general basis, not explicitly checking for None is a source of bugs.
Having a clean return types will help the side-data copies code in future
changesets.
Differential Revision: https://phab.mercurial-scm.org/D7037