A patch changing a symlink into a file is written with 2 sections (in
the code, represented as "struct patch"): firstly, the deletion of the
symlink, and secondly, the creation of the file. When applying that
patch with -R, the sections are reversed, so we get:
(1) creation of a symlink, then
(2) deletion of a file.
This causes an issue when the "deletion of a file" section is checked,
because Git observes that the so-called file is not a file but a
symlink, resulting in a "wrong type" error message.
What we want is:
(1) deletion of a file, then
(2) creation of a symlink.
In the code, this is reflected in the behavior of previous_patch() when
invoked from check_preimage() when the deletion is checked. Creation
then deletion means that when the deletion is checked, previous_patch()
returns the creation section, triggering a mode conflict resulting in
the "wrong type" error message. But deletion then creation means that
when the deletion is checked, previous_patch() returns NULL, so the
deletion mode is checked against lstat, which is what we want.
There are also other ways a patch can contain 2 sections referencing the
same file, for example, in 7a07841c0b ("git-apply: handle a patch that
touches the same path more than once better", 2008-06-27). "git apply
-R" fails in the same way, and this commit makes this case succeed.
Therefore, when building the list of sections, build them in reverse
order (by adding to the front of the list instead of the back) when -R
is passed.
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In t4023 and t4114, we have to remove the entries using 'git rm' because
otherwise the entries that must turn from symbolic links to regular files
would stay symbolic links in the index. For the same reason, we have to
use 'git mv' instead of plain 'mv' in t3509.
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the tests that skipped due to unavailable SYMLINKS support to
use the three-arg prereq form of test_expect_success.
Now we get an indication of how many tests that need symlinks are
being skipped on platforms that don't support them.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
SKIP messages are now part of the TAP plan. A TAP harness now knows
why a particular test was skipped and can report that information. The
non-TAP harness built into Git's test-lib did nothing special with
these messages, and is unaffected by these changes.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Many tests depend on that symbolic links work. This introduces a check
that sets the prerequisite tag SYMLINKS if the file system supports
symbolic links. Since so many tests have to check for this prerequisite,
we do the check in test-lib.sh, so that we don't need to repeat the test
in many scripts.
To check for 'ln -s' failures, you can use a FAT partition on Linux:
$ mkdosfs -C git-on-fat 1000000
$ sudo mount -o loop,uid=j6t,gid=users,shortname=winnt git-on-fat /mnt
Clone git to /mnt and
$ GIT_SKIP_TESTS='t0001.1[34] t0010 t1301 t403[34] t4129.[47] t5701.7
t7701.3 t9100 t9101.26 t9119 t9124.[67] t9200.10 t9600.6' \
make test
(These additionally skipped tests depend on POSIX permissions that FAT on
Linux does not provide.)
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
A patch that changes the filetype (e.g. regular file to symlink) of a path
must be split into a deletion event followed by a creation event, which
means that we need to have two independent metainfo lines for each.
However, the code reused the single set of metainfo lines.
As the blob object names recorded on the index lines are usually not used
nor validated on the receiving end, this is not an issue with normal use
of the resulting patch. However, when accepting a binary patch to delete
a blob, git-apply verified that the postimage blob object name on the
index line is 0{40}, hence a patch that deletes a regular file blob that
records binary contents to create a blob with different filetype (e.g. a
symbolic link) failed to apply. "git am -3" also uses the blob object
names recorded on the index line, so it would also misbehave when
synthesizing a preimage tree.
This moves the code to generate metainfo lines around, so that two
independent sets of metainfo lines are used for the split halves.
Additional tests by Jeff King.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
I've found that git apply is incapable of handling patches
involving object type changes to the same path.
Of course git itself is perfectly capable of making commits that
generate these changes, as it only tracks trees states. It's
just that the diffs between them are less useful if they can't
be applied.
Some of these are rare, but I've hit one of them (file becoming
a symlink) recently in real-world usage, and was inspired to
find more potential breakages :)
I'm not sure when I'll have time to fix these myself and I'm not
very familiar with the apply code. So if someone could get
some or all of these cases working, they would be my hero :)
Some of these are what I would refer to as corner-cases from
hell. Most (if not all) other systems fail some of these. In
fact, they aren't even capable of representing most of these
changes in their histories; much less being able to handle
patches to that effect.
Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>
