apply tests: ensure we can patch a modified file

Patch application need not be on an unmodified file; applying to an
already changed file is supported provided the patch still applies
cleanly.  Add tests that modifies the contents of a file then applies
the patch and ensures that the patch applies cleanly, and the original
changes are also kept.

tests/apply/both.c

@@ -279,3 +279,46 @@ void test_apply_both__keeps_nonconflicting_changes(void)
 
 	git_diff_free(diff);
 }
+
+void test_apply_both__can_apply_nonconflicting_file_changes(void)
+{
+	git_diff *diff;
+	git_index *index;
+	git_apply_options opts = GIT_APPLY_OPTIONS_INIT;
+
+	const char *diff_file = DIFF_MODIFY_TWO_FILES;
+
+	struct merge_index_entry both_expected[] = {
+		{ 0100644, "f8a701c8a1a22c1729ee50faff1111f2d64f96fc", 0, "asparagus.txt" },
+		{ 0100644, "68f6182f4c85d39e1309d97c7e456156dc9c0096", 0, "beef.txt" },
+		{ 0100644, "4b7c5650008b2e747fe1809eeb5a1dde0e80850a", 0, "bouilli.txt" },
+		{ 0100644, "c4e6cca3ec6ae0148ed231f97257df8c311e015f", 0, "gravy.txt" },
+		{ 0100644, "68af1fc7407fd9addf1701a87eb1c95c7494c598", 0, "oyster.txt" },
+		{ 0100644, "a7b066537e6be7109abfe4ff97b675d4e077da20", 0, "veal.txt" },
+	};
+	size_t both_expected_cnt = sizeof(both_expected) /
+		sizeof(struct merge_index_entry);
+
+	/*
+	 * Replace the workdir file with a version that is different than
+	 * HEAD but such that the patch still applies cleanly.  This item
+	 * has a new line appended.
+	 */
+	cl_git_append2file("merge-recursive/asparagus.txt",
+	    "This line is added in the index and the workdir.\n");
+
+	cl_git_pass(git_repository_index(&index, repo));
+	git_index_add_bypath(index, "asparagus.txt");
+	cl_git_pass(git_index_write(index));
+	git_index_free(index);
+
+	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+
+	opts.location = GIT_APPLY_LOCATION_BOTH;
+	cl_git_pass(git_apply(repo, diff, &opts));
+
+	validate_apply_index(repo, both_expected, both_expected_cnt);
+	validate_apply_workdir(repo, both_expected, both_expected_cnt);
+
+	git_diff_free(diff);
+}

tests/apply/index.c

@@ -269,3 +269,51 @@ void test_apply_index__keeps_nonconflicting_changes(void)
 
 	git_diff_free(diff);
 }
+
+void test_apply_index__can_apply_nonconflicting_file_changes(void)
+{
+	git_diff *diff;
+	git_index *index;
+	git_index_entry idx_entry;
+	git_apply_options opts = GIT_APPLY_OPTIONS_INIT;
+
+	const char *diff_file = DIFF_MODIFY_TWO_FILES;
+
+	struct merge_index_entry index_expected[] = {
+		{ 0100644, "4f2d1645dee99ced096877911de540c65ade2ef8", 0, "asparagus.txt" },
+		{ 0100644, "68f6182f4c85d39e1309d97c7e456156dc9c0096", 0, "beef.txt" },
+		{ 0100644, "4b7c5650008b2e747fe1809eeb5a1dde0e80850a", 0, "bouilli.txt" },
+		{ 0100644, "c4e6cca3ec6ae0148ed231f97257df8c311e015f", 0, "gravy.txt" },
+		{ 0100644, "68af1fc7407fd9addf1701a87eb1c95c7494c598", 0, "oyster.txt" },
+		{ 0100644, "a7b066537e6be7109abfe4ff97b675d4e077da20", 0, "veal.txt" },
+	};
+	size_t index_expected_cnt = sizeof(index_expected) /
+		sizeof(struct merge_index_entry);
+
+	/*
+	 * Replace the index entry with a version that is different than
+	 * HEAD but such that the patch still applies cleanly.  This item
+	 * has a new line appended.
+	 */
+
+	cl_git_pass(git_repository_index(&index, repo));
+
+	memset(&idx_entry, 0, sizeof(git_index_entry));
+	idx_entry.mode = 0100644;
+	idx_entry.path = "asparagus.txt";
+	cl_git_pass(git_oid_fromstr(&idx_entry.id, "06d3fefb8726ab1099acc76e02dfb85e034b2538"));
+	cl_git_pass(git_index_add(index, &idx_entry));
+
+	cl_git_pass(git_index_write(index));
+	git_index_free(index);
+
+	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+
+	opts.location = GIT_APPLY_LOCATION_INDEX;
+	cl_git_pass(git_apply(repo, diff, &opts));
+
+	validate_apply_index(repo, index_expected, index_expected_cnt);
+	validate_workdir_unchanged(repo);
+
+	git_diff_free(diff);
+}

tests/apply/workdir.c

@@ -243,3 +243,37 @@ void test_apply_workdir__keeps_nonconflicting_changes(void)
 
 	git_diff_free(diff);
 }
+
+void test_apply_workdir__can_apply_nonconflicting_file_changes(void)
+{
+	git_diff *diff;
+
+	const char *diff_file = DIFF_MODIFY_TWO_FILES;
+
+	struct merge_index_entry workdir_expected[] = {
+		{ 0100644, "5db1a0fef164cb66cc0c00d35cc5af979ddc1a64", 0, "asparagus.txt" },
+		{ 0100644, "68f6182f4c85d39e1309d97c7e456156dc9c0096", 0, "beef.txt" },
+		{ 0100644, "4b7c5650008b2e747fe1809eeb5a1dde0e80850a", 0, "bouilli.txt" },
+		{ 0100644, "c4e6cca3ec6ae0148ed231f97257df8c311e015f", 0, "gravy.txt" },
+		{ 0100644, "68af1fc7407fd9addf1701a87eb1c95c7494c598", 0, "oyster.txt" },
+		{ 0100644, "a7b066537e6be7109abfe4ff97b675d4e077da20", 0, "veal.txt" },
+	};
+	size_t workdir_expected_cnt = sizeof(workdir_expected) /
+		sizeof(struct merge_index_entry);
+
+	/*
+	 * Replace the workdir file with a version that is different than
+	 * HEAD but such that the patch still applies cleanly.  This item
+	 * has a new line appended.
+	 */
+	cl_git_append2file("merge-recursive/asparagus.txt",
+	    "This line is added in the workdir.\n");
+
+	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(git_apply(repo, diff, NULL));
+
+	validate_index_unchanged(repo);
+	validate_apply_workdir(repo, workdir_expected, workdir_expected_cnt);
+
+	git_diff_free(diff);
+}