filectx: fix cmp() of file starting with '\1\n'
If file data starts with '\1\n', it will be escaped in the revlog to
create an empty metadata block, thus adding four bytes to the size in
the revlog size index. There's no way to detect that this has happened
in filelog.size() faster than decompressing each revision [1].
For filectx.cmp(), we have the size of the file in the working directory
available. If it differs by exactly four bytes, it may be this case, so
do a full comparison.
[1]: http://markmail.org/message/5akdbmmqx7vq2fsg
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 4 changes to 4 files
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4 files updated, 0 files merged, 0 files removed, 0 files unresolved
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 4 changes to 4 files
updating to branch default
4 files updated, 0 files merged, 0 files removed, 0 files unresolved