transaction: open a file with checkambig=True to avoid file stat ambiguity
Before this patch, if steps below occurs at "the same time in sec",
all of mtime, ctime and size are same between (1) and (3).
1. append data to revlog-style file (and close transaction)
2. discard appended data by truncation of rollback
3. append same size but different data to revlog-style file again
Therefore, cache validation doesn't work after (3) as expected.
To avoid file stat ambiguity around truncation, this patch opens a
file with checkambig=True.
This is a part of ExactCacheValidationPlan.
https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan
Mercurial
=========
Mercurial is a fast, easy to use, distributed revision control tool
for software developers.
Basic install:
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
Running without installing:
$ make local # build for inplace usage
$ ./hg --version # should show the latest version
See https://mercurial-scm.org/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.