remote: optionally report unchanged tips

include/git2/remote.h

@@ -77,6 +77,17 @@ typedef enum {
 } git_remote_create_flags;
 
 /**
+ * How to handle reference updates.
+ */
+typedef enum {
+	/* Write the fetch results to FETCH_HEAD. */
+	GIT_REMOTE_UPDATE_FETCHHEAD = (1 << 0),
+
+	/* Report unchanged tips in the update_tips callback. */
+	GIT_REMOTE_UPDATE_REPORT_UNCHANGED = (1 << 1)
+} git_remote_update_flags;
+
+/**
  * Remote creation options structure
  *
  * Initialize with `GIT_REMOTE_CREATE_OPTIONS_INIT`. Alternatively, you can
@@ -733,10 +744,10 @@ typedef struct {
 	git_fetch_prune_t prune;
 
 	/**
-	 * Whether to write the results to FETCH_HEAD. Defaults to
-	 * on. Leave this default in order to behave like git.
+	 * How to handle reference updates; a combination of
+	 * `git_remote_update_flags`.
 	 */
-	int update_fetchhead;
+	unsigned int update_flags;
 
 	/**
 	 * Determines how to behave regarding tags on the remote, such
@@ -775,8 +786,13 @@ typedef struct {
 } git_fetch_options;
 
 #define GIT_FETCH_OPTIONS_VERSION 1
-#define GIT_FETCH_OPTIONS_INIT { GIT_FETCH_OPTIONS_VERSION, GIT_REMOTE_CALLBACKS_INIT, GIT_FETCH_PRUNE_UNSPECIFIED, 1, \
-				 GIT_REMOTE_DOWNLOAD_TAGS_UNSPECIFIED, GIT_PROXY_OPTIONS_INIT }
+#define GIT_FETCH_OPTIONS_INIT { \
+	GIT_FETCH_OPTIONS_VERSION, \
+	GIT_REMOTE_CALLBACKS_INIT, \
+	GIT_FETCH_PRUNE_UNSPECIFIED, \
+	GIT_REMOTE_UPDATE_FETCHHEAD, \
+	GIT_REMOTE_DOWNLOAD_TAGS_UNSPECIFIED, \
+	GIT_PROXY_OPTIONS_INIT }
 
 /**
  * Initialize git_fetch_options structure
@@ -1001,7 +1017,7 @@ GIT_EXTERN(int) git_remote_upload(
  * the name of the remote (or its url, for in-memory remotes). This
  * parameter is ignored when pushing.
  * @param callbacks  pointer to the callback structure to use or NULL
- * @param update_fetchhead whether to write to FETCH_HEAD. Pass 1 to behave like git.
+ * @param update_flags the git_remote_update_flags for these tips.
  * @param download_tags what the behaviour for downloading tags is for this fetch. This is
  * ignored for push. This must be the same value passed to `git_remote_download()`.
  * @return 0 or an error code
@@ -1009,7 +1025,7 @@ GIT_EXTERN(int) git_remote_upload(
 GIT_EXTERN(int) git_remote_update_tips(
 		git_remote *remote,
 		const git_remote_callbacks *callbacks,
-		int update_fetchhead,
+		unsigned int update_flags,
 		git_remote_autotag_option_t download_tags,
 		const char *reflog_message);
 

src/libgit2/clone.c

@@ -419,7 +419,7 @@ static int clone_into(
 		return error;
 
 	memcpy(&fetch_opts, opts, sizeof(git_fetch_options));
-	fetch_opts.update_fetchhead = 0;
+	fetch_opts.update_flags = ~GIT_REMOTE_UPDATE_FETCHHEAD;
 
 	if (!opts->depth)
 		fetch_opts.download_tags = GIT_REMOTE_DOWNLOAD_TAGS_ALL;

src/libgit2/remote.c

@@ -1348,13 +1348,14 @@ int git_remote_fetch(
 	const git_fetch_options *opts,
 	const char *reflog_message)
 {
-	int error, update_fetchhead = 1;
 	git_remote_autotag_option_t tagopt = remote->download_tags;
 	bool prune = false;
 	git_str reflog_msg_buf = GIT_STR_INIT;
 	git_remote_connect_options connect_opts = GIT_REMOTE_CONNECT_OPTIONS_INIT;
 	unsigned int capabilities;
 	git_oid_t oid_type;
+	unsigned int update_flags = GIT_REMOTE_UPDATE_FETCHHEAD;
+	int error;
 
 	GIT_ASSERT_ARG(remote);
 
@@ -1371,7 +1372,7 @@ int git_remote_fetch(
 		return error;
 
 	if (opts) {
-		update_fetchhead = opts->update_fetchhead;
+		update_flags = opts->update_flags;
 		tagopt = opts->download_tags;
 	}
 
@@ -1398,8 +1399,14 @@ int git_remote_fetch(
 	}
 
 	/* Create "remote/foo" branches for all remote branches */
-	error = git_remote_update_tips(remote, &connect_opts.callbacks, update_fetchhead, tagopt, git_str_cstr(&reflog_msg_buf));
+	error = git_remote_update_tips(remote,
+		&connect_opts.callbacks,
+		update_flags,
+		tagopt,
+		git_str_cstr(&reflog_msg_buf));
+
 	git_str_dispose(&reflog_msg_buf);
+
 	if (error < 0)
 		goto done;
 
@@ -1774,6 +1781,7 @@ static int update_one_tip(
 	git_refspec *spec,
 	git_remote_head *head,
 	git_refspec *tagspec,
+	unsigned int update_flags,
 	git_remote_autotag_option_t tagopt,
 	const char *log_message,
 	const git_remote_callbacks *callbacks)
@@ -1781,7 +1789,7 @@ static int update_one_tip(
 	git_odb *odb;
 	git_str refname = GIT_STR_INIT;
 	git_reference *ref = NULL;
-	bool autotag = false;
+	bool autotag = false, updated = false;
 	git_oid old;
 	int valid;
 	int error;
@@ -1855,21 +1863,21 @@ static int update_one_tip(
 			goto done;
 	}
 
-	if (!git_oid__cmp(&old, &head->oid))
-		goto done;
+	if ((updated = !git_oid_equal(&old, &head->oid))) {
+		/* In autotag mode, don't overwrite any locally-existing tags */
+		error = git_reference_create(&ref, remote->repo, refname.ptr, &head->oid, !autotag,
+				log_message);
 
-	/* In autotag mode, don't overwrite any locally-existing tags */
-	error = git_reference_create(&ref, remote->repo, refname.ptr, &head->oid, !autotag,
-			log_message);
-
-	if (error < 0) {
-		if (error == GIT_EEXISTS)
-			error = 0;
+		if (error < 0) {
+			if (error == GIT_EEXISTS)
+				error = 0;
 
-		goto done;
+			goto done;
+		}
 	}
 
 	if (callbacks && callbacks->update_tips != NULL &&
+	    (updated || (update_flags & GIT_REMOTE_UPDATE_REPORT_UNCHANGED)) &&
 	    (error = callbacks->update_tips(refname.ptr, &old, &head->oid, callbacks->payload)) < 0)
 		git_error_set_after_callback_function(error, "git_remote_fetch");
 
@@ -1882,7 +1890,7 @@ done:
 static int update_tips_for_spec(
 	git_remote *remote,
 	const git_remote_callbacks *callbacks,
-	int update_fetchhead,
+	unsigned int update_flags,
 	git_remote_autotag_option_t tagopt,
 	git_refspec *spec,
 	git_vector *refs,
@@ -1905,7 +1913,10 @@ static int update_tips_for_spec(
 
 	/* Update tips based on the remote heads */
 	git_vector_foreach(refs, i, head) {
-		if (update_one_tip(&update_heads, remote, spec, head, &tagspec, tagopt, log_message, callbacks) < 0)
+		if (update_one_tip(&update_heads,
+				remote, spec, head, &tagspec,
+				update_flags, tagopt, log_message,
+				callbacks) < 0)
 			goto on_error;
 	}
 
@@ -1927,7 +1938,7 @@ static int update_tips_for_spec(
 			goto on_error;
 	}
 
-	if (update_fetchhead &&
+	if ((update_flags & GIT_REMOTE_UPDATE_FETCHHEAD) &&
 	    (error = git_remote_write_fetchhead(remote, spec, &update_heads)) < 0)
 		goto on_error;
 
@@ -2058,11 +2069,11 @@ static int truncate_fetch_head(const char *gitdir)
 }
 
 int git_remote_update_tips(
-		git_remote *remote,
-		const git_remote_callbacks *callbacks,
-		int update_fetchhead,
-		git_remote_autotag_option_t download_tags,
-		const char *reflog_message)
+	git_remote *remote,
+	const git_remote_callbacks *callbacks,
+	unsigned int update_flags,
+	git_remote_autotag_option_t download_tags,
+	const char *reflog_message)
 {
 	git_refspec *spec, tagspec;
 	git_vector refs = GIT_VECTOR_INIT;
@@ -2091,7 +2102,7 @@ int git_remote_update_tips(
 		goto out;
 
 	if (tagopt == GIT_REMOTE_DOWNLOAD_TAGS_ALL) {
-		if ((error = update_tips_for_spec(remote, callbacks, update_fetchhead, tagopt, &tagspec, &refs, reflog_message)) < 0)
+		if ((error = update_tips_for_spec(remote, callbacks, update_flags, tagopt, &tagspec, &refs, reflog_message)) < 0)
 			goto out;
 	}
 
@@ -2099,7 +2110,7 @@ int git_remote_update_tips(
 		if (spec->push)
 			continue;
 
-		if ((error = update_tips_for_spec(remote, callbacks, update_fetchhead, tagopt, spec, &refs, reflog_message)) < 0)
+		if ((error = update_tips_for_spec(remote, callbacks, update_flags, tagopt, spec, &refs, reflog_message)) < 0)
 			goto out;
 	}
 

tests/libgit2/online/fetch.c

@@ -128,6 +128,8 @@ void test_online_fetch__doesnt_retrieve_a_pack_when_the_repository_is_up_to_date
 	git_clone_options opts = GIT_CLONE_OPTIONS_INIT;
 	opts.bare = true;
 
+	counter = 0;
+
 	cl_git_pass(git_clone(&_repository, "https://github.com/libgit2/TestGitRepository.git",
 				"./fetch/lg2", &opts));
 	git_repository_free(_repository);
@@ -141,11 +143,52 @@ void test_online_fetch__doesnt_retrieve_a_pack_when_the_repository_is_up_to_date
 
 	options.callbacks.transfer_progress = &transferProgressCallback;
 	options.callbacks.payload = &invoked;
+	options.callbacks.update_tips = update_tips;
 	cl_git_pass(git_remote_download(remote, NULL, &options));
 
 	cl_assert_equal_i(false, invoked);
 
-	cl_git_pass(git_remote_update_tips(remote, &options.callbacks, 1, options.download_tags, NULL));
+	cl_git_pass(git_remote_update_tips(remote, &options.callbacks, GIT_REMOTE_UPDATE_FETCHHEAD, options.download_tags, NULL));
+	cl_assert_equal_i(0, counter);
+
+	git_remote_disconnect(remote);
+
+	git_remote_free(remote);
+	git_repository_free(_repository);
+}
+
+void test_online_fetch__report_unchanged_tips(void)
+{
+	git_repository *_repository;
+	bool invoked = false;
+	git_remote *remote;
+	git_fetch_options options = GIT_FETCH_OPTIONS_INIT;
+	git_clone_options opts = GIT_CLONE_OPTIONS_INIT;
+	opts.bare = true;
+
+	counter = 0;
+
+	cl_git_pass(git_clone(&_repository, "https://github.com/libgit2/TestGitRepository.git",
+				"./fetch/lg2", &opts));
+	git_repository_free(_repository);
+
+	cl_git_pass(git_repository_open(&_repository, "./fetch/lg2"));
+
+	cl_git_pass(git_remote_lookup(&remote, _repository, "origin"));
+	cl_git_pass(git_remote_connect(remote, GIT_DIRECTION_FETCH, NULL, NULL, NULL));
+
+	cl_assert_equal_i(false, invoked);
+
+	options.callbacks.transfer_progress = &transferProgressCallback;
+	options.callbacks.payload = &invoked;
+	options.callbacks.update_tips = update_tips;
+	cl_git_pass(git_remote_download(remote, NULL, &options));
+
+	cl_assert_equal_i(false, invoked);
+
+	cl_git_pass(git_remote_update_tips(remote, &options.callbacks, GIT_REMOTE_UPDATE_REPORT_UNCHANGED, options.download_tags, NULL));
+	cl_assert(counter > 0);
+
 	git_remote_disconnect(remote);
 
 	git_remote_free(remote);