Reproduction steps

Add the following test to test/merge/driver.c:

void test_merge_driver__binary(void)
{
const char *expected = "this file is changed in master and branch\n";
const git_index_entry *ancestor, *ours, *theirs;

// Make merge do a binary merge for conflicting.txt by writing "*.txt -merge" to the
// .gitattributes file.
git_buf line = GIT_BUF_INIT;
git_buf_printf(&line, "*.txt -merge\n");
cl_assert(!git_buf_oom(&line));
cl_git_mkfile(TEST_REPO_PATH "/.gitattributes", line.ptr);
git_buf_dispose(&line);


merge_branch();


cl_git_pass(git_index_conflict_get(&ancestor, &ours, &theirs,
repo_index, "conflicting.txt"));

cl_assert_equal_file(expected, strlen(expected),
TEST_REPO_PATH "/conflicting.txt");
}

Here it is in a branch on my fork:

master...lrm29:git_merge_checkout_binary_contains_conflict_markers

The test first writes "*.txt -merge" to the .gitattributes file. It then calls the function merge_branch(), which is defined in tests/merge/driver.c and is a small wrapper around the function git_merge.

The first assertion shows that conflicting.txt is correctly identified as a conflict.

The second assertion that checks the contents of conflicting.txt fails. The problem is that even though "*.txt -merge" has been written to the .gitattributes file, a text merge has been performed when creating the contents of conflicting.txt in the working tree.

Expected behavior

Contents of conflicting.txt are:

this file is changed in master and branch

Actual behavior

Contents of conflicting.txt are:

 <<<<<<< HEAD
 this file is changed in master and branch
 =======
 this file is changed in branch and master
 >>>>>>>

Version of libgit2 (release number or SHA1)

6bd37c3

Operating system(s) tested

Debian 9, but will be OS agnostic.