Improve diff config options handling

This makes diff use the cvar cache for config options where
possible, and also adds support for a number of other config
options to diff including "diff.context", "diff.ignoreSubmodules",
"diff.noprefix", "diff.mnemonicprefix", and "core.abbrev".

To make this natural, this involved a rearrangement of the code
that allocates the diff object vs. the code that initializes it
based on the combination of options passed in by the user and
read from the config.

This commit includes tests for most of these new options as well.

1 files changed, 74 insertions, 0 deletions

diff --git a/tests-clar/diff/tree.c b/tests-clar/diff/tree.c
index 850feefde..f05c7869e 100644
--- a/tests-clar/diff/tree.c
+++ b/tests-clar/diff/tree.c
@@ -454,3 +454,77 @@ void test_diff_tree__issue_1397(void)
 	cl_assert_equal_i(0, expect.file_status[GIT_DELTA_ADDED]);
 	cl_assert_equal_i(0, expect.file_status[GIT_DELTA_TYPECHANGE]);
 }
+
+static void set_config_int(git_repository *repo, const char *name, int value)
+{
+	git_config *cfg;
+
+	cl_git_pass(git_repository_config(&cfg, repo));
+	cl_git_pass(git_config_set_int32(cfg, name, value));
+	git_config_free(cfg);
+}
+
+void test_diff_tree__diff_configs(void)
+{
+	const char *a_commit = "d70d245e";
+	const char *b_commit = "7a9e0b02";
+
+	g_repo = cl_git_sandbox_init("diff");
+
+	cl_assert((a = resolve_commit_oid_to_tree(g_repo, a_commit)) != NULL);
+	cl_assert((b = resolve_commit_oid_to_tree(g_repo, b_commit)) != NULL);
+
+	cl_git_pass(git_diff_tree_to_tree(&diff, g_repo, a, b, NULL));
+
+	cl_git_pass(git_diff_foreach(
+		diff, diff_file_cb, diff_hunk_cb, diff_line_cb, &expect));
+
+	cl_assert_equal_i(2, expect.files);
+	cl_assert_equal_i(2, expect.file_status[GIT_DELTA_MODIFIED]);
+	cl_assert_equal_i(6, expect.hunks);
+	cl_assert_equal_i(55, expect.lines);
+	cl_assert_equal_i(33, expect.line_ctxt);
+	cl_assert_equal_i(7, expect.line_adds);
+	cl_assert_equal_i(15, expect.line_dels);
+
+	git_diff_list_free(diff);
+	diff = NULL;
+
+	set_config_int(g_repo, "diff.context", 1);
+
+	memset(&expect, 0, sizeof(expect));
+
+	cl_git_pass(git_diff_tree_to_tree(&diff, g_repo, a, b, NULL));
+
+	cl_git_pass(git_diff_foreach(
+		diff, diff_file_cb, diff_hunk_cb, diff_line_cb, &expect));
+
+	cl_assert_equal_i(2, expect.files);
+	cl_assert_equal_i(2, expect.file_status[GIT_DELTA_MODIFIED]);
+	cl_assert_equal_i(7, expect.hunks);
+	cl_assert_equal_i(34, expect.lines);
+	cl_assert_equal_i(12, expect.line_ctxt);
+	cl_assert_equal_i(7, expect.line_adds);
+	cl_assert_equal_i(15, expect.line_dels);
+
+	git_diff_list_free(diff);
+	diff = NULL;
+
+	set_config_int(g_repo, "diff.context", 0);
+	set_config_int(g_repo, "diff.noprefix", 1);
+
+	memset(&expect, 0, sizeof(expect));
+
+	cl_git_pass(git_diff_tree_to_tree(&diff, g_repo, a, b, NULL));
+
+	cl_git_pass(git_diff_foreach(
+		diff, diff_file_cb, diff_hunk_cb, diff_line_cb, &expect));
+
+	cl_assert_equal_i(2, expect.files);
+	cl_assert_equal_i(2, expect.file_status[GIT_DELTA_MODIFIED]);
+	cl_assert_equal_i(7, expect.hunks);
+	cl_assert_equal_i(22, expect.lines);
+	cl_assert_equal_i(0, expect.line_ctxt);
+	cl_assert_equal_i(7, expect.line_adds);
+	cl_assert_equal_i(15, expect.line_dels);
+}