tests: add script to disable a selected wire protocol capability
This can be used to test that the client and server both fall back to the
previous wire protocol when the capability is not supported.
It is currently used by test-push-http.t and I plan to use it for the HTTP
long argument support tests.
$ "$TESTDIR/hghave" execbit || exit 80
$ hg init
$ echo a > a
$ hg ci -Am'not executable'
adding a
$ chmod +x a
$ hg ci -m'executable'
$ hg id
79abf14474dc tip
Make sure we notice the change of mode if the cached size == -1:
$ hg rm a
$ hg revert -r 0 a
$ hg debugstate
n 0 -1 unset a
$ hg status
M a
$ hg up 0
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg id
d69afc33ff8a
$ test -x a && echo executable -- bad || echo not executable -- good
not executable -- good