git_submodule_update does not clone and throws assertion #4149
Description
Hi all,
Libgit2 crashes (throws assertion) during the git_submodule_update function.
It may very well be that I don't use it correctly, as the documentation is not entirely exact in how to clone/add a submodule and I haven't found any examples either.
Reproduction steps
First a script to setup the environment and then the actual code.
script to setup the environment
setup script, first the submodule which should be later added and then the parent directory.
The submodule is set up in /tmp, because I want absolute paths.
setup.sh:
#!/bin/bash
# remove previous fixtures
# commented to not delete any stuff if you just copy and pasted it.
#rm -rf /tmp/sm_test
#rm -rf parent
pushd .
# setup submodule
mkdir /tmp/sm_test && cd /tmp/sm_test
git init .
touch sm_file
git add sm_file
git commit -m "initial commit in submodule"
cd ..
popd
pushd .
# setup parent repository
mkdir parent && cd parent
git init .
touch parent_file
git add parent_file
git commit -m "initial commit in parent"
popd
minimal code for the bug
bug.c:
#include <git2.h>
#include <assert.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
git_submodule* sm = NULL;
git_repository* parent = NULL;
int result = 0;
git_libgit2_init();
result = git_repository_open(&parent, "parent");
assert(!result);
result = git_submodule_add_setup(&sm, parent, "file:///tmp/sm_test", "sm_test", 0);
assert(!result);
result = git_submodule_update(sm, 1, NULL);
assert(!result);
result = git_submodule_add_finalize(sm);
assert(!result);
git_submodule_free(sm);
git_repository_free(parent);
git_libgit2_shutdown();
return 0;
}
Then just compile and run the whole stuff:
gcc bug.c -o bug -lgit2 && ./setup.sh && ./bug
Expected behavior
The submodule should be cloned correctly and libgit2 shouldn't crash.
parent/sm_test should contain the cloned repository.
Actual behavior
The program crashes with the following
bug: /home/user/build/libgit2/src/object.c:122: git_object_lookup_prefix: Assertion `repo && object_out && id' failed.
(id is zero)
Version of libgit2 (release number or SHA1)
HEAD is at ba2bc4911d99e20f1060bb6767edab94fd5d97a6
Operating system(s) tested
$ uname -a
Linux arch_virt_pci_test 4.8.13-1-ARCH #1 SMP PREEMPT Fri Dec 9 07:24:34 CET 2016 x86_64 GNU/Linux
Further information
Backtrace
#0 0x00007ffff773a04f in raise () from /usr/lib/libc.so.6
#1 0x00007ffff773b47a in abort () from /usr/lib/libc.so.6
#2 0x00007ffff7732ea7 in __assert_fail_base () from /usr/lib/libc.so.6
#3 0x00007ffff7732f52 in __assert_fail () from /usr/lib/libc.so.6
#4 0x00007ffff7b1c095 in git_object_lookup_prefix (object_out=0x7fffffffdbd0, repo=0x72a0b0, id=0x0, len=40, type=GIT_OBJ_COMMIT)
at /home/andre/build/libgit2/src/object.c:122
#5 0x00007ffff7b1c29e in git_object_lookup (object_out=0x7fffffffdbd0, repo=0x72a0b0, id=0x0, type=GIT_OBJ_COMMIT)
at /home/andre/build/libgit2/src/object.c:198
#6 0x00007ffff7b66a22 in git_submodule_update (sm=0x72ab70, init=1, _update_options=0x0) at /home/andre/build/libgit2/src/submodule.c:1224
#7 0x000000000040093c in main (argc=1, argv=0x7fffffffdd28) at bug.c:20
Links to the corresponding lines:
git_object_lookup_prefix @ src/object.c:122: Link
git_object_lookup @ src/object.c:198: Link
git_submodule_update @ src/submodule.c:1224: Link
Directory contents after bug
$ ls parent/
parent_file sm_test
$ cat parent/.gitmodules
[submodule "sm_test"]
path = sm_test
url = file:///tmp/sm_test
$ ls parent/sm_test/
$ ls /tmp/sm_test/
sm_file
So, the directory is created (per add_setup), but the index is not cloned.
If you need further information, please ask.
Cheers,
Andre