refs: Introduce git_reference_symbolic_set_target_with_log()

include/git2/refs.h

@@ -319,6 +319,31 @@ GIT_EXTERN(int) git_reference_symbolic_set_target(
 
 /**
  * Create a new reference with the same name as the given reference but a
+ * different symbolic target  and update the reflog with a given message.
+ *
+ * The reference must be a symbolic reference, otherwise this will fail.
+ *
+ * The new reference will be written to disk, overwriting the given reference.
+ *
+ * The target name will be checked for validity.
+ * See `git_reference_create_symbolic()` for rules about valid names.
+ *
+ * @param out Pointer to the newly created reference
+ * @param ref The reference
+ * @param target The new target for the reference
+ * @param signature The identity that will used to populate the reflog entry
+ * @param log_message The one line long message that has to be appended
+ * @return 0 on success, EINVALIDSPEC or an error code
+ */
+GIT_EXTERN(int) git_reference_symbolic_set_target_with_log(
+	git_reference **out,
+	git_reference *ref,
+	const char *target,
+	const git_signature *signature,
+	const char *log_message);
+
+/**
+ * Create a new reference with the same name as the given reference but a
  * different OID target. The reference must be a direct reference, otherwise
  * this will fail.
  *

src/refs.c

@@ -523,22 +523,49 @@ int git_reference_set_target_with_log(
 		out, ref->db->repo, ref->name, id, 1, signature, log_message);
 }
 
+static int ensure_is_an_updatable_symbolic_reference(git_reference *ref)
+{
+	if (ref->type == GIT_REF_SYMBOLIC)
+		return 0;
+
+	giterr_set(GITERR_REFERENCE, "Cannot set symbolic target on a direct reference");
+	return -1;
+}
+
 int git_reference_symbolic_set_target(
 	git_reference **out,
 	git_reference *ref,
 	const char *target)
 {
+	int error;
+
 	assert(out && ref && target);
 
-	if (ref->type != GIT_REF_SYMBOLIC) {
-		giterr_set(GITERR_REFERENCE,
-			"Cannot set symbolic target on a direct reference");
-		return -1;
-	}
+	if ((error = ensure_is_an_updatable_symbolic_reference(ref)) < 0)
+		return error;
 
 	return git_reference_symbolic_create(out, ref->db->repo, ref->name, target, 1);
 }
 
+int git_reference_symbolic_set_target_with_log(
+	git_reference **out,
+	git_reference *ref,
+	const char *target,
+	const git_signature *signature,
+	const char *log_message)
+{
+	int error;
+
+	assert(out && ref && target);
+	assert(signature && log_message);
+
+	if ((error = ensure_is_an_updatable_symbolic_reference(ref)) < 0)
+		return error;
+
+	return git_reference_symbolic_create_with_log(
+		out, ref->db->repo, ref->name, target, 1, signature, log_message);
+}
+
 int git_reference_rename(
 	git_reference **out,
 	git_reference *ref,

tests/refs/settargetwithlog.c

@@ -53,3 +53,42 @@ void test_refs_settargetwithlog__updating_a_direct_reference_adds_a_reflog_entry
 	git_reference_free(reference);
 	git_signature_free(signature);
 }
+
+void test_refs_settargetwithlog__updating_a_symbolic_reference_adds_a_reflog_entry(void)
+{
+	git_reference *reference, *reference_out;
+	git_oid id;
+	git_signature *signature;
+	git_reflog *reflog;
+	const git_reflog_entry *entry;
+
+	const char *name = "HEAD";
+	const char *message = "You've been logged, mate!";
+
+	git_oid_fromstr(&id, br2_tip);
+
+	cl_git_pass(git_signature_now(&signature, "foo", "foo@bar"));
+	
+	cl_git_pass(git_reference_lookup(&reference, g_repo, name));
+
+	cl_assert_equal_s(
+		"refs/heads/master", git_reference_symbolic_target(reference));
+
+	cl_git_pass(git_reference_symbolic_set_target_with_log(&reference_out,
+		reference, br2_name, signature, message));
+
+	cl_assert_equal_s(
+		br2_name, git_reference_symbolic_target(reference_out));
+
+	cl_git_pass(git_reflog_read(&reflog, reference));
+
+	entry = git_reflog_entry_byindex(reflog, 0);
+	cl_assert(git_oid_streq(&entry->oid_old, master_tip) == 0);
+	cl_assert(git_oid_streq(&entry->oid_cur, br2_tip) == 0);
+	cl_assert_equal_s(message, entry->msg);
+
+	git_reflog_free(reflog);
+	git_reference_free(reference_out);
+	git_reference_free(reference);
+	git_signature_free(signature);
+}