refs: Introduce git_reference_create_with_log()

include/git2/refs.h

@@ -130,6 +130,49 @@ GIT_EXTERN(int) git_reference_symbolic_create(git_reference **out, git_repositor
  */
 GIT_EXTERN(int) git_reference_create(git_reference **out, git_repository *repo, const char *name, const git_oid *id, int force);
 
+/**
+ * Create a new direct reference and update the reflog with a given
+ * message.
+ *
+ * A direct reference (also called an object id reference) refers directly
+ * to a specific object id (a.k.a. OID or SHA) in the repository.  The id
+ * permanently refers to the object (although the reference itself can be
+ * moved).  For example, in libgit2 the direct ref "refs/tags/v0.17.0"
+ * refers to OID 5b9fac39d8a76b9139667c26a63e6b3f204b3977.
+ *
+ * The direct reference will be created in the repository and written to
+ * the disk.  The generated reference object must be freed by the user.
+ *
+ * Valid reference names must follow one of two patterns:
+ *
+ * 1. Top-level names must contain only capital letters and underscores,
+ *    and must begin and end with a letter. (e.g. "HEAD", "ORIG_HEAD").
+ * 2. Names prefixed with "refs/" can be almost anything.  You must avoid
+ *    the characters '~', '^', ':', '\\', '?', '[', and '*', and the
+ *    sequences ".." and "@{" which have special meaning to revparse.
+ *
+ * This function will return an error if a reference already exists with the
+ * given name unless `force` is true, in which case it will be overwritten.
+ *
+ * @param out Pointer to the newly created reference
+ * @param repo Repository where that reference will live
+ * @param name The name of the reference
+ * @param id The object id pointed to by the reference.
+ * @param force Overwrite existing references
+ * @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
+ * to the reflog
+ * @return 0 on success, EEXISTS, EINVALIDSPEC or an error code
+ */
+GIT_EXTERN(int) git_reference_create_with_log(
+	git_reference **out,
+	git_repository *repo,
+	const char *name,
+	const git_oid *id,
+	int force,
+	const git_signature *signature,
+	const char *log_message);
+
 /**
  * Get the OID pointed to by a direct reference.
  *

src/refs.c

@@ -322,13 +322,44 @@ const char *git_reference_symbolic_target(const git_reference *ref)
 	return ref->target.symbolic;
 }
 
+static int feed_reflog(
+	const git_reference *ref,
+	const git_signature *signature,
+	const char *log_message)
+{
+
+	git_reflog *reflog = NULL;
+	git_oid peeled_ref_oid;
+	int error;
+
+	if ((error = git_reflog_read(&reflog, ref)) < 0)
+		goto cleanup;
+
+	if ((error = git_reference_name_to_id(&peeled_ref_oid,
+		git_reference_owner(ref), git_reference_name(ref))) < 0)
+			goto cleanup;
+
+	if ((error = git_reflog_append(reflog, &peeled_ref_oid, 
+		signature, log_message)) < 0)
+			goto cleanup;
+
+	error = git_reflog_write(reflog);
+
+cleanup:
+	git_reflog_free(reflog);
+
+	return 0;
+}
+
 static int reference__create(
 	git_reference **ref_out,
 	git_repository *repo,
 	const char *name,
 	const git_oid *oid,
 	const char *symbolic,
-	int force)
+	int force,
+	const git_signature *signature,
+	const char *log_message)
 {
 	char normalized[GIT_REFNAME_MAX];
 	git_refdb *refdb;
@@ -336,6 +367,7 @@ static int reference__create(
 	int error = 0;
 
 	assert(repo && name);
+	assert(!((signature == NULL) ^ (log_message == NULL)));
 
 	if (ref_out)
 		*ref_out = NULL;
@@ -381,6 +413,11 @@ static int reference__create(
 		return error;
 	}
 
+	if (log_message && (error = feed_reflog(ref, signature, log_message)) < 0) {
+		git_reference_free(ref);
+		return error;
+	}
+
 	if (ref_out == NULL)
 		git_reference_free(ref);
 	else
@@ -398,7 +435,22 @@ int git_reference_create(
 {
 	assert(oid);
 
-	return reference__create(ref_out, repo, name, oid, NULL, force);
+	return reference__create(ref_out, repo, name, oid, NULL, force, NULL, NULL);
+}
+
+int git_reference_create_with_log(
+	git_reference **ref_out,
+	git_repository *repo,
+	const char *name,
+	const git_oid *oid,
+	int force,
+	const git_signature *signature,
+	const char *log_message)
+{
+	assert(oid && signature && log_message);
+
+	return reference__create(
+		ref_out, repo, name, oid, NULL, force, signature, log_message);
 }
 
 int git_reference_symbolic_create(
@@ -410,7 +462,7 @@ int git_reference_symbolic_create(
 {
 	assert(target);
 
-	return reference__create(ref_out, repo, name, NULL, target, force);
+	return reference__create(ref_out, repo, name, NULL, target, force, NULL, NULL);
 }
 
 int git_reference_set_target(

tests/refs/createwithlog.c

@@ -0,0 +1,52 @@
+#include "clar_libgit2.h"
+
+#include "repository.h"
+#include "git2/reflog.h"
+#include "reflog.h"
+#include "ref_helpers.h"
+
+static const char *current_master_tip = "a65fedf39aefe402d3bb6e24df4d4f5fe4547750";
+static const char *current_head_target = "refs/heads/master";
+
+static git_repository *g_repo;
+
+void test_refs_createwithlog__initialize(void)
+{
+   g_repo = cl_git_sandbox_init("testrepo.git");
+}
+
+void test_refs_createwithlog__cleanup(void)
+{
+   cl_git_sandbox_cleanup();
+}
+
+void test_refs_createwithlog__creating_a_direct_reference_adds_a_reflog_entry(void)
+{
+	git_reference *reference;
+	git_oid id;
+	git_signature *signature;
+	git_reflog *reflog;
+	const git_reflog_entry *entry;
+
+	const char *name = "refs/heads/new-head";
+	const char *message = "You've been logged, mate!";
+
+	git_oid_fromstr(&id, current_master_tip);
+
+	cl_git_pass(git_signature_now(&signature, "foo", "foo@bar"));
+
+	cl_git_pass(
+		git_reference_create_with_log(&reference, g_repo, name, &id, 0, signature, message));
+
+	cl_git_pass(git_reflog_read(&reflog, reference));
+	cl_assert_equal_sz(1, git_reflog_entrycount(reflog));
+
+	entry = git_reflog_entry_byindex(reflog, 0);
+	cl_assert(git_oid_streq(&entry->oid_old, GIT_OID_HEX_ZERO) == 0);
+	cl_assert(git_oid_cmp(&id, &entry->oid_cur) == 0);
+	cl_assert_equal_s(message, entry->msg);
+
+	git_reflog_free(reflog);
+	git_reference_free(reference);
+	git_signature_free(signature);
+}