rust-revlog: fix RevlogEntry.data() for NULL_REVISION
Before this change, the pseudo-entry returned by `Revlog.get_entry` for
`NULL_REVISION` would trigger errors in application code using it.
For example, this fixes a crash spotted with changelog data
while implementing RHGitaly: `Changelog.data_for_rev(-1)` was already
returning the pseudo content as expected, e.g., for `hg log`, but
`Changelog.entry_for_rev(-1).data()` would still crash with
"corrupted revlog, hash check failed for revision -1". There is
an added test for this scenario.
#require unix-permissions no-root no-windows no-rhg
XXX-RHG this test hangs if `hg` is really `rhg`. This was hidden by the use of
`alias hg=rhg` by run-tests.py. With such alias removed, this test is revealed
buggy. This need to be resolved sooner than later.
repository itself is non-readable
---------------------------------
$ hg init no-read
$ hg id ssh://user@dummy/no-read
000000000000
$ chmod a-rx no-read
$ hg id ssh://user@dummy/no-read
remote: abort: $EACCES$: *$TESTTMP/no-read/.hg* (glob)
abort: no suitable response from remote hg
[255]
special case files are visible, but unreadable
----------------------------------------------
This is "similar" to the test above, but the directory is "traversable". This
seems an unexpected case in real life, but we test it anyway.
$ hg init other
$ hg id ssh://user@dummy/other
000000000000
$ for item in `find other | sort -r` ; do
> chmod a-r $item
> done
$ hg id ssh://user@dummy/other
remote: abort: $EACCES$: '$TESTTMP/other/.hg/requires'
abort: no suitable response from remote hg
[255]
directory toward the repository is read only
--------------------------------------------
$ mkdir deep
$ hg init deep/nested
$ hg id ssh://user@dummy/deep/nested
000000000000
$ chmod a-rx deep
$ hg id ssh://user@dummy/deep/nested
remote: abort: $EACCES$: *$TESTTMP/deep/nested/.hg* (glob)
abort: no suitable response from remote hg
[255]
repository has wrong requirement
--------------------------------
$ hg init repo-future
$ hg id ssh://user@dummy/repo-future
000000000000
$ echo flying-car >> repo-future/.hg/requires
$ hg id ssh://user@dummy/repo-future
remote: abort: repository requires features unknown to this Mercurial: flying-car
remote: (see https://mercurial-scm.org/wiki/MissingRequirement for more information)
abort: no suitable response from remote hg
[255]