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
$ hg init test
$ cd test
$ cat > .hg/hgrc <<EOF
> [extensions]
> interhg =
>
> [interhg]
> issues = s|Issue(\d+)|<a href="http://bts.example.org/issue\1">Issue\1</a>|
>
> # yes, 'x' is a weird delimiter...
> markbugs = sxbugx<i class="\x">bug</i>x
> EOF
$ touch foo
$ hg add foo
$ hg commit -d '1 0' -m 'Issue123: fixed the bug!'
$ hg serve -n test -p $HGPORT -d --pid-file=hg.pid -A access.log -E errors.log
$ cat hg.pid >> $DAEMON_PIDS
log
$ "$TESTDIR/get-with-headers.py" localhost:$HGPORT '/' | grep bts
<td class="description"><a href="/rev/1b0e7ece6bd6"><a href="http://bts.example.org/issue123">Issue123</a>: fixed the <i class="x">bug</i>!</a><span class="branchhead">default</span> <span class="tag">tip</span> </td>
errors
$ cat errors.log