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
Initial setup.
$ hg init repo
$ cd repo
$ touch thefile
$ hg ci -A -m 'Initial commit.'
adding thefile
Create a tag.
$ hg tag branchortag
Create a branch with the same name as the tag.
$ hg branch branchortag
marked working directory as branch branchortag
(branches are permanent and global, did you want a bookmark?)
$ hg ci -m 'Create a branch with the same name as a tag.'
This is what we have:
$ hg log
changeset: 2:10519b3f489a
branch: branchortag
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Create a branch with the same name as a tag.
changeset: 1:2635c45ca99b
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Added tag branchortag for changeset f57387372b5d
changeset: 0:f57387372b5d
tag: branchortag
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Initial commit.
Update to the tag:
$ hg up 'tag(branchortag)'
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg parents
changeset: 0:f57387372b5d
tag: branchortag
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Initial commit.
Updating to the branch:
$ hg up 'branch(branchortag)'
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg parents
changeset: 2:10519b3f489a
branch: branchortag
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Create a branch with the same name as a tag.