Remove converting user error to GIT_EUSER

This changes the behavior of callbacks so that the callback error
code is not converted into GIT_EUSER and instead we propagate the
return value through to the caller.  Instead of using the
giterr_capture and giterr_restore functions, we now rely on all
functions to pass back the return value from a callback.

To avoid having a return value with no error message, the user
can call the public giterr_set_str or some such function to set
an error message.  There is a new helper 'giterr_set_callback'
that functions can invoke after making a callback which ensures
that some error message was set in case the callback did not set
one.

In places where the sign of the callback return value is
meaningful (e.g. positive to skip, negative to abort), only the
negative values are returned back to the caller, obviously, since
the other values allow for continuing the loop.

The hardest parts of this were in the checkout code where positive
return values were overloaded as meaningful values for checkout.
I fixed this by adding an output parameter to many of the internal
checkout functions and removing the overload.  This added some
code, but it is probably a better implementation.

There is some funkiness in the network code where user provided
callbacks could be returning a positive or a negative value and
we want to rely on that to cancel the loop.  There are still a
couple places where an user error might get turned into GIT_EUSER
there, I think, though none exercised by the tests.

1 files changed, 33 insertions, 61 deletions

diff --git a/src/remote.c b/src/remote.c
index 93d243001..307306d1a 100644
--- a/src/remote.c
+++ b/src/remote.c
@@ -251,14 +251,12 @@ int git_remote_create_inmemory(git_remote **out, git_repository *repo, const cha
 struct refspec_cb_data {
 	git_remote *remote;
 	int fetch;
-	git_error_state error;
 };
 
 static int refspec_cb(const git_config_entry *entry, void *payload)
 {
 	struct refspec_cb_data *data = (struct refspec_cb_data *)payload;
-	return giterr_capture(
-		&data->error, add_refspec(data->remote, entry->value, data->fetch));
+	return add_refspec(data->remote, entry->value, data->fetch);
 }
 
 static int get_optional_config(
@@ -316,17 +314,15 @@ int git_remote_load(git_remote **out, git_repository *repo, const char *name)
 	if ((error = get_check_cert(&remote->check_cert, repo)) < 0)
 		goto cleanup;
 
-	if ((git_vector_init(&remote->refs, 32, NULL) < 0) ||
-	    (git_vector_init(&remote->refspecs, 2, NULL) < 0) ||
-	    (git_vector_init(&remote->active_refspecs, 2, NULL) < 0)) {
+	if (git_vector_init(&remote->refs, 32, NULL) < 0 ||
+	    git_vector_init(&remote->refspecs, 2, NULL) < 0 ||
+	    git_vector_init(&remote->active_refspecs, 2, NULL) < 0) {
 		error = -1;
 		goto cleanup;
 	}
 
-	if (git_buf_printf(&buf, "remote.%s.url", name) < 0) {
-		error = -1;
+	if ((error = git_buf_printf(&buf, "remote.%s.url", name)) < 0)
 		goto cleanup;
-	}
 
 	if ((error = get_optional_config(&found, config, &buf, NULL, (void *)&val)) < 0)
 		goto cleanup;
@@ -387,9 +383,6 @@ int git_remote_load(git_remote **out, git_repository *repo, const char *name)
 cleanup:
 	git_buf_free(&buf);
 
-	if (error == GIT_EUSER)
-		error = giterr_restore(&data.error);
-
 	if (error < 0)
 		git_remote_free(remote);
 
@@ -636,7 +629,7 @@ int git_remote_connect(git_remote *remote, git_direction direction)
 	if (!remote->check_cert)
 		flags |= GIT_TRANSPORTFLAGS_NO_CHECK_CERT;
 
-	if ((error = t->connect(t, url, remote->callbacks.credentials, remote->callbacks.payload, direction, flags)) < 0)
+	if ((error = t->connect(t, url, remote->callbacks.credentials, remote->callbacks.payload, direction, flags)) != 0)
 		goto on_error;
 
 	remote->transport = t;
@@ -788,7 +781,7 @@ int git_remote_download(git_remote *remote)
 	git_vector_free(&refs);
 
 	if (error < 0)
-		return -1;
+		return error;
 
 	if ((error = git_fetch_negotiate(remote)) < 0)
 		return error;
@@ -801,10 +794,10 @@ int git_remote_fetch(git_remote *remote)
 	int error;
 
 	/* Connect and download everything */
-	if ((error = git_remote_connect(remote, GIT_DIRECTION_FETCH)) < 0)
+	if ((error = git_remote_connect(remote, GIT_DIRECTION_FETCH)) != 0)
 		return error;
 
-	if ((error = git_remote_download(remote)) < 0)
+	if ((error = git_remote_download(remote)) != 0)
 		return error;
 
 	/* We don't need to be connected anymore */
@@ -1032,7 +1025,6 @@ int git_remote_update_tips(git_remote *remote)
 	int error;
 	size_t i;
 
-
 	if (git_refspec__parse(&tagspec, GIT_REFSPEC_TAGS, true) < 0)
 		return -1;
 
@@ -1112,14 +1104,9 @@ void git_remote_free(git_remote *remote)
 	git__free(remote);
 }
 
-struct remote_list_data {
-	git_vector list;
-	git_error_state error;
-};
-
 static int remote_list_cb(const git_config_entry *entry, void *payload)
 {
-	struct remote_list_data *data = payload;
+	git_vector *list = payload;
 	const char *name = entry->name + strlen("remote.");
 	size_t namelen = strlen(name);
 	char *remote_name;
@@ -1130,42 +1117,35 @@ static int remote_list_cb(const git_config_entry *entry, void *payload)
 		remote_name = git__strndup(name, namelen - 4); /* strip ".url" */
 	else
 		remote_name = git__strndup(name, namelen - 8); /* strip ".pushurl" */
-	if (!remote_name)
-		return giterr_capture(&data->error, -1);
+	GITERR_CHECK_ALLOC(remote_name);
 
-	return giterr_capture(
-		&data->error, git_vector_insert(&data->list, remote_name));
+	return git_vector_insert(list, remote_name);
 }
 
 int git_remote_list(git_strarray *remotes_list, git_repository *repo)
 {
 	int error;
 	git_config *cfg;
-	struct remote_list_data data;
+	git_vector list = GIT_VECTOR_INIT;
 
 	if ((error = git_repository_config__weakptr(&cfg, repo)) < 0)
 		return error;
 
-	memset(&data, 0, sizeof(data));
-	if ((error = git_vector_init(&data.list, 4, git__strcmp_cb)) < 0)
+	if ((error = git_vector_init(&list, 4, git__strcmp_cb)) < 0)
 		return error;
 
 	error = git_config_foreach_match(
-		cfg, "^remote\\..*\\.(push)?url$", remote_list_cb, &data);
-
-	/* cb error is converted to GIT_EUSER by git_config_foreach */
-	if (error == GIT_EUSER)
-		error = giterr_restore(&data.error);
+		cfg, "^remote\\..*\\.(push)?url$", remote_list_cb, &list);
 
 	if (error < 0) {
-		git_vector_free_all(&data.list);
+		git_vector_free_all(&list);
 		return error;
 	}
 
-	git_vector_uniq(&data.list, git__free);
+	git_vector_uniq(&list, git__free);
 
-	remotes_list->strings = (char **)data.list.contents;
-	remotes_list->count = data.list.length;
+	remotes_list->strings =
+		(char **)git_vector_detach(&remotes_list->count, NULL, &list);
 
 	return 0;
 }
@@ -1256,7 +1236,6 @@ struct update_data {
 	git_config *config;
 	const char *old_remote_name;
 	const char *new_remote_name;
-	git_error_state error;
 };
 
 static int update_config_entries_cb(
@@ -1268,9 +1247,8 @@ static int update_config_entries_cb(
 	if (strcmp(entry->value, data->old_remote_name))
 		return 0;
 
-	return giterr_capture(
-		&data->error, git_config_set_string(
-			data->config, entry->name, data->new_remote_name));
+	return git_config_set_string(
+		data->config, entry->name, data->new_remote_name);
 }
 
 static int update_branch_remote_config_entry(
@@ -1287,13 +1265,8 @@ static int update_branch_remote_config_entry(
 	data.old_remote_name = old_name;
 	data.new_remote_name = new_name;
 
-	error = git_config_foreach_match(
+	return git_config_foreach_match(
 		data.config, "branch\\..+\\.remote", update_config_entries_cb, &data);
-
-	if (error == GIT_EUSER)
-		error = giterr_restore(&data.error);
-
-	return error;
 }
 
 static int rename_one_remote_reference(
@@ -1357,13 +1330,14 @@ static int rename_fetch_refspecs(
 	git_buf base = GIT_BUF_INIT, var = GIT_BUF_INIT, val = GIT_BUF_INIT;
 	const git_refspec *spec;
 	size_t i;
-	int error = -1;
-
-	if (git_buf_printf(&base, "+refs/heads/*:refs/remotes/%s/*", remote->name) < 0)
-		goto cleanup;
+	int error = 0;
 
 	if ((error = git_repository_config__weakptr(&config, remote->repo)) < 0)
-		goto cleanup;
+		return error;
+
+	if ((error = git_buf_printf(
+			&base, "+refs/heads/*:refs/remotes/%s/*", remote->name)) < 0)
+		return error;
 
 	git_vector_foreach(&remote->refspecs, i, spec) {
 		if (spec->push)
@@ -1374,10 +1348,9 @@ static int rename_fetch_refspecs(
 		if (!remote->name ||
 			strcmp(git_buf_cstr(&base), spec->string)) {
 
-			if (callback(spec->string, payload) < 0) {
-				error = giterr_user_cancel();
-				goto cleanup;
-			}
+			error = GITERR_CALLBACK( callback(spec->string, payload) );
+			if (error)
+				break;
 			continue;
 		}
 
@@ -1391,15 +1364,14 @@ static int rename_fetch_refspecs(
 			git_buf_printf(&var, "remote.%s.fetch", new_name) < 0)
 		{
 			error = -1;
-			goto cleanup;
+			break;
 		}
 
 		if ((error = git_config_set_string(
 				config, git_buf_cstr(&var), git_buf_cstr(&val))) < 0)
-			goto cleanup;
+			break;
 	}
 
-cleanup:
 	git_buf_free(&base);
 	git_buf_free(&var);
 	git_buf_free(&val);