thodg/libgit2

diff --git a/include/git2/errors.h b/include/git2/errors.h
index 5a4e540..d71df59 100644
--- a/include/git2/errors.h
+++ b/include/git2/errors.h
@@ -123,12 +123,14 @@ typedef struct {
 typedef enum {
 	GITERR_NOMEMORY,
 	GITERR_OS,
+	GITERR_INVALID,
 	GITERR_REFERENCE,
 	GITERR_ZLIB,
 	GITERR_REPOSITORY,
 	GITERR_CONFIG,
 	GITERR_REGEX,
-	GITERR_ODB
+	GITERR_ODB,
+	GITERR_INDEX
 } git_error_class;
 
 /**
diff --git a/src/fileops.c b/src/fileops.c
index 65942ad..f1f820a 100644
--- a/src/fileops.c
+++ b/src/fileops.c
@@ -108,10 +108,10 @@ mode_t git_futils_canonical_mode(mode_t raw_mode)
 		return S_IFREG | GIT_CANONICAL_PERMS(raw_mode);
 	else if (S_ISLNK(raw_mode))
 		return S_IFLNK;
-	else if (S_ISDIR(raw_mode))
-		return S_IFDIR;
 	else if (S_ISGITLINK(raw_mode))
 		return S_IFGITLINK;
+	else if (S_ISDIR(raw_mode))
+		return S_IFDIR;
 	else
 		return 0;
 }
diff --git a/src/index.c b/src/index.c
index 7f5909a..216ede7 100644
--- a/src/index.c
+++ b/src/index.c
@@ -135,19 +135,14 @@ int git_index_open(git_index **index_out, const char *index_path)
 
 	assert(index_out && index_path);
 
-	index = git__malloc(sizeof(git_index));
-	if (index == NULL)
-		return GIT_ENOMEM;
-
-	memset(index, 0x0, sizeof(git_index));
+	index = git__calloc(1, sizeof(git_index));
+	GITERR_CHECK_ALLOC(index);
 
 	index->index_file_path = git__strdup(index_path);
-	if (index->index_file_path == NULL) {
-		git__free(index);
-		return GIT_ENOMEM;
-	}
+	GITERR_CHECK_ALLOC(index->index_file_path);
 
-	git_vector_init(&index->entries, 32, index_cmp);
+	if (git_vector_init(&index->entries, 32, index_cmp) < 0)
+		return -1;
 
 	/* Check if index file is stored on disk already */
 	if (git_path_exists(index->index_file_path) == true)
@@ -215,7 +210,7 @@ void git_index_clear(git_index *index)
 
 int git_index_read(git_index *index)
 {
-	int error = GIT_SUCCESS, updated;
+	int error, updated;
 	git_buf buffer = GIT_BUF_INIT;
 	time_t mtime;
 
@@ -224,27 +219,26 @@ int git_index_read(git_index *index)
 	if (!index->on_disk || git_path_exists(index->index_file_path) == false) {
 		git_index_clear(index);
 		index->on_disk = 0;
-		return GIT_SUCCESS;
+		return 0;
 	}
 
 	/* We don't want to update the mtime if we fail to parse the index */
 	mtime = index->last_modified;
-	error = git_futils_readbuffer_updated(&buffer, index->index_file_path, &mtime, &updated);
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to read index");
+	error = git_futils_readbuffer_updated(
+		&buffer, index->index_file_path, &mtime, &updated);
+	if (error < 0)
+		return error;
 
 	if (updated) {
 		git_index_clear(index);
 		error = parse_index(index, buffer.ptr, buffer.size);
 
-		if (error == GIT_SUCCESS)
+		if (!error)
 			index->last_modified = mtime;
 
 		git_buf_free(&buffer);
 	}
 
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to parse index");
 	return error;
 }
 
@@ -256,23 +250,24 @@ int git_index_write(git_index *index)
 
 	git_vector_sort(&index->entries);
 
-	if ((error = git_filebuf_open(&file, index->index_file_path, GIT_FILEBUF_HASH_CONTENTS)) < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to write index");
+	if ((error = git_filebuf_open(
+			 &file, index->index_file_path, GIT_FILEBUF_HASH_CONTENTS)) < 0)
+		return error;
 
-	if ((error = write_index(index, &file)) < GIT_SUCCESS) {
+	if ((error = write_index(index, &file)) < 0) {
 		git_filebuf_cleanup(&file);
-		return git__rethrow(error, "Failed to write index");
+		return error;
 	}
 
-	if ((error = git_filebuf_commit(&file, GIT_INDEX_FILE_MODE)) < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to write index");
+	if ((error = git_filebuf_commit(&file, GIT_INDEX_FILE_MODE)) < 0)
+		return error;
 
 	if (p_stat(index->index_file_path, &indexst) == 0) {
 		index->last_modified = indexst.st_mtime;
 		index->on_disk = 1;
 	}
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 unsigned int git_index_entrycount(git_index *index)
@@ -293,6 +288,20 @@ git_index_entry *git_index_get(git_index *index, unsigned int n)
 	return git_vector_get(&index->entries, n);
 }
 
+void git_index__init_entry_from_stat(struct stat *st, git_index_entry *entry)
+{
+	entry->ctime.seconds = (git_time_t)st->st_ctime;
+	entry->mtime.seconds = (git_time_t)st->st_mtime;
+	/* entry->mtime.nanoseconds = st->st_mtimensec; */
+	/* entry->ctime.nanoseconds = st->st_ctimensec; */
+	entry->dev  = st->st_rdev;
+	entry->ino  = st->st_ino;
+	entry->mode = index_create_mode(st->st_mode);
+	entry->uid  = st->st_uid;
+	entry->gid  = st->st_gid;
+	entry->file_size = st->st_size;
+}
+
 static int index_entry_init(git_index_entry **entry_out, git_index *index, const char *rel_path, int stage)
 {
 	git_index_entry *entry = NULL;
@@ -302,21 +311,17 @@ static int index_entry_init(git_index_entry **entry_out, git_index *index, const
 	git_buf full_path = GIT_BUF_INIT;
 	int error;
 
-	if (INDEX_OWNER(index) == NULL)
-		return git__throw(GIT_EBAREINDEX,
-			"Failed to initialize entry. Repository is bare");
-
-	if (stage < 0 || stage > 3)
-		return git__throw(GIT_ERROR,
-			"Failed to initialize entry. Invalid stage %i", stage);
+	assert(stage >= 0 && stage <= 3);
 
-	workdir = git_repository_workdir(INDEX_OWNER(index));
-	if (workdir == NULL)
-		return git__throw(GIT_EBAREINDEX,
-			"Failed to initialize entry. Cannot resolved workdir");
+	if (INDEX_OWNER(index) == NULL ||
+		(workdir = git_repository_workdir(INDEX_OWNER(index))) == NULL)
+	{
+		giterr_set(GITERR_INDEX,
+			"Could not initialize index entry. Repository is bare");
+		return -1;
+	}
 
-	error = git_buf_joinpath(&full_path, workdir, rel_path);
-	if (error < GIT_SUCCESS)
+	if ((error = git_buf_joinpath(&full_path, workdir, rel_path)) < 0)
 		return error;
 
 	if ((error = git_path_lstat(full_path.ptr, &st)) < 0) {
@@ -331,34 +336,21 @@ static int index_entry_init(git_index_entry **entry_out, git_index *index, const
 	 */
 
 	/* write the blob to disk and get the oid */
-	if ((error = git_blob_create_fromfile(&oid, INDEX_OWNER(index), rel_path)) < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to initialize index entry");
+	if ((error = git_blob_create_fromfile(&oid, INDEX_OWNER(index), rel_path)) < 0)
+		return error;
 
 	entry = git__calloc(1, sizeof(git_index_entry));
-	if (!entry)
-		return GIT_ENOMEM;
-
-	entry->ctime.seconds = (git_time_t)st.st_ctime;
-	entry->mtime.seconds = (git_time_t)st.st_mtime;
-	/* entry.mtime.nanoseconds = st.st_mtimensec; */
-	/* entry.ctime.nanoseconds = st.st_ctimensec; */
-	entry->dev= st.st_rdev;
-	entry->ino = st.st_ino;
-	entry->mode = index_create_mode(st.st_mode);
-	entry->uid = st.st_uid;
-	entry->gid = st.st_gid;
-	entry->file_size = st.st_size;
-	entry->oid = oid;
+	GITERR_CHECK_ALLOC(entry);
 
+	git_index__init_entry_from_stat(&st, entry);
+
+	entry->oid = oid;
 	entry->flags |= (stage << GIT_IDXENTRY_STAGESHIFT);
 	entry->path = git__strdup(rel_path);
-	if (entry->path == NULL) {
-		git__free(entry);
-		return GIT_ENOMEM;
-	}
+	GITERR_CHECK_ALLOC(entry->path);
 
 	*entry_out = entry;
-	return GIT_SUCCESS;
+	return 0;
 }
 
 static git_index_entry *index_entry_dup(const git_index_entry *source_entry)
@@ -393,10 +385,7 @@ static int index_insert(git_index *index, git_index_entry *entry, int replace)
 	int position;
 	git_index_entry **entry_array;
 
-	assert(index && entry);
-
-	if (entry->path == NULL)
-		return git__throw(GIT_EMISSINGOBJDATA, "Failed to insert into index. Entry has no path");
+	assert(index && entry && entry->path != NULL);
 
 	/* make sure that the path length flag is correct */
 	path_length = strlen(entry->path);
@@ -412,12 +401,8 @@ static int index_insert(git_index *index, git_index_entry *entry, int replace)
 	 * replacing is not requested: just insert entry at the end;
 	 * the index is no longer sorted
 	 */
-	if (!replace) {
-		if (git_vector_insert(&index->entries, entry) < GIT_SUCCESS)
-			return GIT_ENOMEM;
-
-		return GIT_SUCCESS;
-	}
+	if (!replace)
+		return git_vector_insert(&index->entries, entry);
 
 	/* look if an entry with this path already exists */
 	position = git_index_find(index, entry->path);
@@ -426,12 +411,8 @@ static int index_insert(git_index *index, git_index_entry *entry, int replace)
 	 * if no entry exists add the entry at the end;
 	 * the index is no longer sorted
 	 */
-	if (position == GIT_ENOTFOUND) {
-		if (git_vector_insert(&index->entries, entry) < GIT_SUCCESS)
-			return GIT_ENOMEM;
-
-		return GIT_SUCCESS;
-	}
+	if (position == GIT_ENOTFOUND)
+		return git_vector_insert(&index->entries, entry);
 
 	/* exists, replace it */
 	entry_array = (git_index_entry **) index->entries.contents;
@@ -439,7 +420,7 @@ static int index_insert(git_index *index, git_index_entry *entry, int replace)
 	git__free(entry_array[position]);
 	entry_array[position] = entry;
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 static int index_add(git_index *index, const char *path, int stage, int replace)
@@ -447,20 +428,15 @@ static int index_add(git_index *index, const char *path, int stage, int replace)
 	git_index_entry *entry = NULL;
 	int ret;
 
-	ret = index_entry_init(&entry, index, path, stage);
-	if (ret)
-		goto err;
-
-	ret = index_insert(index, entry, replace);
-	if (ret)
-		goto err;
+	if ((ret = index_entry_init(&entry, index, path, stage)) < 0 ||
+		(ret = index_insert(index, entry, replace)) < 0)
+	{
+		index_entry_free(entry);
+		return ret;
+	}
 
 	git_tree_cache_invalidate_path(index->tree, entry->path);
-
-	return ret;
-err:
-	index_entry_free(entry);
-	return git__rethrow(ret, "Failed to append to index");
+	return 0;
 }
 
 int git_index_add(git_index *index, const char *path, int stage)
@@ -473,28 +449,23 @@ int git_index_append(git_index *index, const char *path, int stage)
 	return index_add(index, path, stage, 0);
 }
 
-static int index_add2(git_index *index, const git_index_entry *source_entry,
-		int replace)
+static int index_add2(
+	git_index *index, const git_index_entry *source_entry, int replace)
 {
 	git_index_entry *entry = NULL;
 	int ret;
 
 	entry = index_entry_dup(source_entry);
-	if (entry == NULL) {
-		ret = GIT_ENOMEM;
-		goto err;
-	}
+	if (entry == NULL)
+		return -1;
 
-	ret = index_insert(index, entry, replace);
-	if (ret)
-		goto err;
+	if ((ret = index_insert(index, entry, replace)) < 0) {
+		index_entry_free(entry);
+		return ret;
+	}
 
 	git_tree_cache_invalidate_path(index->tree, entry->path);
-
-	return ret;
-err:
-	index_entry_free(entry);
-	return git__rethrow(ret, "Failed to append to index");
+	return 0;
 }
 
 int git_index_add2(git_index *index, const git_index_entry *source_entry)
@@ -513,13 +484,14 @@ int git_index_remove(git_index *index, int position)
 	git_index_entry *entry;
 
 	git_vector_sort(&index->entries);
+
 	entry = git_vector_get(&index->entries, position);
 	if (entry != NULL)
 		git_tree_cache_invalidate_path(index->tree, entry->path);
 
 	error = git_vector_remove(&index->entries, (unsigned int)position);
 
-	if (error == GIT_SUCCESS)
+	if (!error)
 		index_entry_free(entry);
 
 	return error;
@@ -535,7 +507,8 @@ void git_index_uniq(git_index *index)
 	git_vector_uniq(&index->entries);
 }
 
-const git_index_entry_unmerged *git_index_get_unmerged_bypath(git_index *index, const char *path)
+const git_index_entry_unmerged *git_index_get_unmerged_bypath(
+	git_index *index, const char *path)
 {
 	int pos;
 	assert(index && path);
@@ -549,69 +522,81 @@ const git_index_entry_unmerged *git_index_get_unmerged_bypath(git_index *index, 
 	return git_vector_get(&index->unmerged, pos);
 }
 
-const git_index_entry_unmerged *git_index_get_unmerged_byindex(git_index *index, unsigned int n)
+const git_index_entry_unmerged *git_index_get_unmerged_byindex(
+	git_index *index, unsigned int n)
 {
 	assert(index);
 	return git_vector_get(&index->unmerged, n);
 }
 
+static int index_error_invalid(const char *message)
+{
+	giterr_set(GITERR_INDEX, "Invalid data in index - %s", message);
+	return -1;
+}
+
 static int read_unmerged(git_index *index, const char *buffer, size_t size)
 {
 	const char *endptr;
 	size_t len;
 	int i;
 
-	git_vector_init(&index->unmerged, 16, unmerged_cmp);
+	if (git_vector_init(&index->unmerged, 16, unmerged_cmp) < 0)
+		return -1;
 
 	while (size) {
 		git_index_entry_unmerged *lost;
 
 		len = strlen(buffer) + 1;
 		if (size <= len)
-			return git__throw(GIT_ERROR, "Failed to read unmerged entries");
+			return index_error_invalid("reading unmerged entries");
 
-		if ((lost = git__malloc(sizeof(git_index_entry_unmerged))) == NULL)
-			return GIT_ENOMEM;
+		lost = git__malloc(sizeof(git_index_entry_unmerged));
+		GITERR_CHECK_ALLOC(lost);
 
-		if (git_vector_insert(&index->unmerged, lost) < GIT_SUCCESS)
-			return git__throw(GIT_ERROR, "Failed to read unmerged entries");
+		if (git_vector_insert(&index->unmerged, lost) < 0)
+			return -1;
 
+		/* read NUL-terminated pathname for entry */
 		lost->path = git__strdup(buffer);
-		if (!lost->path)
-			return GIT_ENOMEM;
+		GITERR_CHECK_ALLOC(lost->path);
 
 		size -= len;
 		buffer += len;
 
+		/* read 3 ASCII octal numbers for stage entries */
 		for (i = 0; i < 3; i++) {
 			int tmp;
 
-			if (git__strtol32(&tmp, buffer, &endptr, 8) < GIT_SUCCESS ||
-				!endptr || endptr == buffer || *endptr || (unsigned)tmp > UINT_MAX)
-				return GIT_ERROR;
+			if (git__strtol32(&tmp, buffer, &endptr, 8) < 0 ||
+				!endptr || endptr == buffer || *endptr ||
+				(unsigned)tmp > UINT_MAX)
+				return index_error_invalid("reading unmerged entry stage");
 
 			lost->mode[i] = tmp;
 
 			len = (endptr + 1) - buffer;
 			if (size <= len)
-				return git__throw(GIT_ERROR, "Failed to read unmerged entries");
+				return index_error_invalid("reading unmerged entry stage");
 
 			size -= len;
 			buffer += len;
 		}
 
+		/* read up to 3 OIDs for stage entries */
 		for (i = 0; i < 3; i++) {
 			if (!lost->mode[i])
 				continue;
 			if (size < 20)
-				return git__throw(GIT_ERROR, "Failed to read unmerged entries");
+				return index_error_invalid("reading unmerged entry oid");
+
 			git_oid_fromraw(&lost->oid[i], (const unsigned char *) buffer);
 			size -= 20;
 			buffer += 20;
 		}
 	}
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 static size_t read_entry(git_index_entry *dest, const void *buffer, size_t buffer_size)
@@ -657,7 +642,7 @@ static size_t read_entry(git_index_entry *dest, const void *buffer, size_t buffe
 
 		path_end = memchr(path_ptr, '\0', buffer_size);
 		if (path_end == NULL)
-				return 0;
+			return 0;
 
 		path_length = path_end - path_ptr;
 	}
@@ -682,15 +667,15 @@ static int read_header(struct index_header *dest, const void *buffer)
 
 	dest->signature = ntohl(source->signature);
 	if (dest->signature != INDEX_HEADER_SIG)
-		return GIT_EOBJCORRUPTED;
+		return index_error_invalid("incorrect header signature");
 
 	dest->version = ntohl(source->version);
 	if (dest->version != INDEX_VERSION_NUMBER_EXT &&
 		dest->version != INDEX_VERSION_NUMBER)
-		return GIT_EOBJCORRUPTED;
+		return index_error_invalid("incorrect header version");
 
 	dest->entry_count = ntohl(source->entry_count);
-	return GIT_SUCCESS;
+	return 0;
 }
 
 static size_t read_extension(git_index *index, const char *buffer, size_t buffer_size)
@@ -713,10 +698,10 @@ static size_t read_extension(git_index *index, const char *buffer, size_t buffer
 	if (dest.signature[0] >= 'A' && dest.signature[0] <= 'Z') {
 		/* tree cache */
 		if (memcmp(dest.signature, INDEX_EXT_TREECACHE_SIG, 4) == 0) {
-			if (git_tree_cache_read(&index->tree, buffer + 8, dest.extension_size) < GIT_SUCCESS)
+			if (git_tree_cache_read(&index->tree, buffer + 8, dest.extension_size) < 0)
 				return 0;
 		} else if (memcmp(dest.signature, INDEX_EXT_UNMERGED_SIG, 4) == 0) {
-			if (read_unmerged(index, buffer + 8, dest.extension_size) < GIT_SUCCESS)
+			if (read_unmerged(index, buffer + 8, dest.extension_size) < 0)
 				return 0;
 		}
 		/* else, unsupported extension. We cannot parse this, but we can skip
@@ -738,21 +723,21 @@ static int parse_index(git_index *index, const char *buffer, size_t buffer_size)
 
 #define seek_forward(_increase) { \
 	if (_increase >= buffer_size) \
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to seek forward. Buffer size exceeded"); \
+		return index_error_invalid("ran out of data while parsing"); \
 	buffer += _increase; \
 	buffer_size -= _increase;\
 }
 
 	if (buffer_size < INDEX_HEADER_SIZE + INDEX_FOOTER_SIZE)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse index. Buffer too small");
+		return index_error_invalid("insufficient buffer space");
 
 	/* Precalculate the SHA1 of the files's contents -- we'll match it to
 	 * the provided SHA1 in the footer */
 	git_hash_buf(&checksum_calculated, buffer, buffer_size - INDEX_FOOTER_SIZE);
 
 	/* Parse header */
-	if (read_header(&header, buffer) < GIT_SUCCESS)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse index. Header is corrupted");
+	if (read_header(&header, buffer) < 0)
+		return -1;
 
 	seek_forward(INDEX_HEADER_SIZE);
 
@@ -764,23 +749,22 @@ static int parse_index(git_index *index, const char *buffer, size_t buffer_size)
 		git_index_entry *entry;
 
 		entry = git__malloc(sizeof(git_index_entry));
-		if (entry == NULL)
-			return GIT_ENOMEM;
+		GITERR_CHECK_ALLOC(entry);
 
 		entry_size = read_entry(entry, buffer, buffer_size);
 
 		/* 0 bytes read means an object corruption */
 		if (entry_size == 0)
-			return git__throw(GIT_EOBJCORRUPTED, "Failed to parse index. Entry size is zero");
+			return index_error_invalid("invalid entry");
 
-		if (git_vector_insert(&index->entries, entry) < GIT_SUCCESS)
-			return GIT_ENOMEM;
+		if (git_vector_insert(&index->entries, entry) < 0)
+			return -1;
 
 		seek_forward(entry_size);
 	}
 
 	if (i != header.entry_count)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse index. Header entries changed while parsing");
+		return index_error_invalid("header entries changed while parsing");
 
 	/* There's still space for some extensions! */
 	while (buffer_size > INDEX_FOOTER_SIZE) {
@@ -790,43 +774,43 @@ static int parse_index(git_index *index, const char *buffer, size_t buffer_size)
 
 		/* see if we have read any bytes from the extension */
 		if (extension_size == 0)
-			return git__throw(GIT_EOBJCORRUPTED, "Failed to parse index. Extension size is zero");
+			return index_error_invalid("extension size is zero");
 
 		seek_forward(extension_size);
 	}
 
 	if (buffer_size != INDEX_FOOTER_SIZE)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse index. Buffer size does not match index footer size");
+		return index_error_invalid("buffer size does not match index footer size");
 
 	/* 160-bit SHA-1 over the content of the index file before this checksum. */
 	git_oid_fromraw(&checksum_expected, (const unsigned char *)buffer);
 
 	if (git_oid_cmp(&checksum_calculated, &checksum_expected) != 0)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse index. Calculated checksum does not match expected checksum");
+		return index_error_invalid("calculated checksum does not match expected");
 
 #undef seek_forward
 
 	/* force sorting in the vector: the entries are
 	 * assured to be sorted on the index */
 	index->entries.sorted = 1;
-	return GIT_SUCCESS;
+	return 0;
 }
 
 static int is_index_extended(git_index *index)
 {
 	unsigned int i, extended;
+	git_index_entry *entry;
 
 	extended = 0;
 
-	for (i = 0; i < index->entries.length; ++i) {
-		git_index_entry *entry;
-		entry = git_vector_get(&index->entries, i);
+	git_vector_foreach(&index->entries, i, entry) {
 		entry->flags &= ~GIT_IDXENTRY_EXTENDED;
 		if (entry->flags_extended & GIT_IDXENTRY_EXTENDED_FLAGS) {
 			extended++;
 			entry->flags |= GIT_IDXENTRY_EXTENDED;
 		}
 	}
+
 	return extended;
 }
 
@@ -844,8 +828,8 @@ static int write_disk_entry(git_filebuf *file, git_index_entry *entry)
 	else
 		disk_size = short_entry_size(path_len);
 
-	if (git_filebuf_reserve(file, &mem, disk_size) < GIT_SUCCESS)
-		return GIT_ENOMEM;
+	if (git_filebuf_reserve(file, &mem, disk_size) < 0)
+		return -1;
 
 	ondisk = (struct entry_short *)mem;
 
@@ -887,7 +871,7 @@ static int write_disk_entry(git_filebuf *file, git_index_entry *entry)
 
 	memcpy(path, entry->path, path_len);
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 static int write_entries(git_index *index, git_filebuf *file)
@@ -897,16 +881,15 @@ static int write_entries(git_index *index, git_filebuf *file)
 	for (i = 0; i < index->entries.length; ++i) {
 		git_index_entry *entry;
 		entry = git_vector_get(&index->entries, i);
-		if (write_disk_entry(file, entry) < GIT_SUCCESS)
-			return GIT_ENOMEM;
+		if (write_disk_entry(file, entry) < 0)
+			return -1;
 	}
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 static int write_index(git_index *index, git_filebuf *file)
 {
-	int error = GIT_SUCCESS;
 	git_oid hash_final;
 
 	struct index_header header;
@@ -921,11 +904,11 @@ static int write_index(git_index *index, git_filebuf *file)
 	header.version = htonl(is_extended ? INDEX_VERSION_NUMBER_EXT : INDEX_VERSION_NUMBER);
 	header.entry_count = htonl(index->entries.length);
 
-	git_filebuf_write(file, &header, sizeof(struct index_header));
+	if (git_filebuf_write(file, &header, sizeof(struct index_header)) < 0)
+		return -1;
 
-	error = write_entries(index, file);
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to write index");
+	if (write_entries(index, file) < 0)
+		return -1;
 
 	/* TODO: write extensions (tree cache) */
 
@@ -933,9 +916,7 @@ static int write_index(git_index *index, git_filebuf *file)
 	git_filebuf_hash(&hash_final, file);
 
 	/* write it at the end of the file */
-	git_filebuf_write(file, hash_final.id, GIT_OID_RAWSZ);
-
-	return error == GIT_SUCCESS ? GIT_SUCCESS : git__rethrow(error, "Failed to write index");
+	return git_filebuf_write(file, hash_final.id, GIT_OID_RAWSZ);
 }
 
 int git_index_entry_stage(const git_index_entry *entry)
@@ -945,36 +926,30 @@ int git_index_entry_stage(const git_index_entry *entry)
 
 static int read_tree_cb(const char *root, git_tree_entry *tentry, void *data)
 {
-	int ret = GIT_SUCCESS;
 	git_index *index = data;
 	git_index_entry *entry = NULL;
 	git_buf path = GIT_BUF_INIT;
 
 	if (entry_is_tree(tentry))
-		goto exit;
+		return 0;
 
-	ret = git_buf_joinpath(&path, root, tentry->filename);
-	if (ret < GIT_SUCCESS)
-		goto exit;
+	if (git_buf_joinpath(&path, root, tentry->filename) < 0)
+		return -1;
 
 	entry = git__calloc(1, sizeof(git_index_entry));
-	if (!entry) {
-		ret = GIT_ENOMEM;
-		goto exit;
-	}
+	GITERR_CHECK_ALLOC(entry);
 
 	entry->mode = tentry->attr;
 	entry->oid = tentry->oid;
 	entry->path = git_buf_detach(&path);
-
-	ret = index_insert(index, entry, 0);
-
-exit:
 	git_buf_free(&path);
 
-	if (ret < GIT_SUCCESS)
+	if (index_insert(index, entry, 0) < 0) {
 		index_entry_free(entry);
-	return ret;
+		return -1;
+	}
+
+	return 0;
 }
 
 int git_index_read_tree(git_index *index, git_tree *tree)
diff --git a/src/index.h b/src/index.h
index 4f03652..e745c8f 100644
--- a/src/index.h
+++ b/src/index.h
@@ -31,4 +31,6 @@ struct git_index {
 	git_vector unmerged;
 };
 
+extern void git_index__init_entry_from_stat(struct stat *st, git_index_entry *entry);
+
 #endif
diff --git a/src/indexer.c b/src/indexer.c
index 6f8bd32..b5d6397 100644
--- a/src/indexer.c
+++ b/src/indexer.c
@@ -49,17 +49,22 @@ static int parse_header(git_indexer *idx)
 	int error;
 
 	/* Verify we recognize this pack file format. */
-	if ((error = p_read(idx->pack->mwf.fd, &idx->hdr, sizeof(idx->hdr))) < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to read in pack header");
-
-	if (idx->hdr.hdr_signature != ntohl(PACK_SIGNATURE))
-		return git__throw(GIT_EOBJCORRUPTED, "Wrong pack signature");
+	if ((error = p_read(idx->pack->mwf.fd, &idx->hdr, sizeof(idx->hdr))) < 0) {
+		giterr_set(GITERR_OS, "Failed to read in pack header");
+		return error;
+	}
 
-	if (!pack_version_ok(idx->hdr.hdr_version))
-		return git__throw(GIT_EOBJCORRUPTED, "Wrong pack version");
+	if (idx->hdr.hdr_signature != ntohl(PACK_SIGNATURE)) {
+		giterr_set(GITERR_INVALID, "Wrong pack signature");
+		return -1;
+	}
 
+	if (!pack_version_ok(idx->hdr.hdr_version)) {
+		giterr_set(GITERR_INVALID, "Wrong pack version");
+		return -1;
+	}
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 static int objects_cmp(const void *a, const void *b)
@@ -87,49 +92,43 @@ int git_indexer_new(git_indexer **out, const char *packname)
 
 	assert(out && packname);
 
-	if (git_path_root(packname) < 0)
-		return git__throw(GIT_EINVALIDPATH, "Path is not absolute");
-
-	idx = git__malloc(sizeof(git_indexer));
-	if (idx == NULL)
-		return GIT_ENOMEM;
+	if (git_path_root(packname) < 0) {
+		giterr_set(GITERR_INVALID, "Path is not absolute");
+		return -1;
+	}
 
-	memset(idx, 0x0, sizeof(*idx));
+	idx = git__calloc(1, sizeof(git_indexer));
+	GITERR_CHECK_ALLOC(idx);
 
 	namelen = strlen(packname);
-	idx->pack = git__malloc(sizeof(struct git_pack_file) + namelen + 1);
-	if (idx->pack == NULL) {
-		error = GIT_ENOMEM;
-		goto cleanup;
-	}
+	idx->pack = git__calloc(1, sizeof(struct git_pack_file) + namelen + 1);
+	GITERR_CHECK_ALLOC(idx->pack);
 
-	memset(idx->pack, 0x0, sizeof(struct git_pack_file));
 	memcpy(idx->pack->pack_name, packname, namelen + 1);
 
-	ret = p_stat(packname, &idx->st);
-	if (ret < 0) {
-		if (errno == ENOENT)
-			error = git__throw(GIT_ENOTFOUND, "Failed to stat packfile. File not found");
-		else
-			error = git__throw(GIT_EOSERR, "Failed to stat packfile.");
+	if ((ret = p_stat(packname, &idx->st)) < 0) {
+		if (errno == ENOENT) {
+			giterr_set(GITERR_OS, "Failed to stat packfile. File not found");
+			error = GIT_ENOTFOUND;
+		} else {
+			giterr_set(GITERR_OS, "Failed to stat packfile.");
+			error = -1;
+		}
 
 		goto cleanup;
 	}
 
-	ret = p_open(idx->pack->pack_name, O_RDONLY);
-	if (ret < 0) {
-		error = git__throw(GIT_EOSERR, "Failed to open packfile");
+	if ((ret = p_open(idx->pack->pack_name, O_RDONLY)) < 0) {
+		giterr_set(GITERR_OS, "Failed to open packfile.");
+		error = -1;
 		goto cleanup;
 	}
 
 	idx->pack->mwf.fd = ret;
 	idx->pack->mwf.size = (git_off_t)idx->st.st_size;
 
-	error = parse_header(idx);
-	if (error < GIT_SUCCESS) {
-		error = git__rethrow(error, "Failed to parse packfile header");
+	if ((error = parse_header(idx)) < 0)
 		goto cleanup;
-	}
 
 	idx->nr_objects = ntohl(idx->hdr.hdr_entries);
 
@@ -137,17 +136,17 @@ int git_indexer_new(git_indexer **out, const char *packname)
 	assert(idx->nr_objects == (size_t)((unsigned int)idx->nr_objects));
 
 	error = git_vector_init(&idx->pack->cache, (unsigned int)idx->nr_objects, cache_cmp);
-	if (error < GIT_SUCCESS)
+	if (error < 0)
 		goto cleanup;
 
 	idx->pack->has_cache = 1;
 	error = git_vector_init(&idx->objects, (unsigned int)idx->nr_objects, objects_cmp);
-	if (error < GIT_SUCCESS)
+	if (error < 0)
 		goto cleanup;
 
 	*out = idx;
 
-	return GIT_SUCCESS;
+	return 0;
 
 cleanup:
 	git_indexer_free(idx);
@@ -165,8 +164,8 @@ static int index_path(git_buf *path, git_indexer *idx)
 		slash--;
 
 	if (git_buf_grow(path, slash + 1 + strlen(prefix) +
-					 GIT_OID_HEXSZ + strlen(suffix) + 1) < GIT_SUCCESS)
-		return GIT_ENOMEM;
+					 GIT_OID_HEXSZ + strlen(suffix) + 1) < 0)
+		return -1;
 
 	git_buf_truncate(path, slash);
 	git_buf_puts(path, prefix);
@@ -174,10 +173,7 @@ static int index_path(git_buf *path, git_indexer *idx)
 	path->size += GIT_OID_HEXSZ;
 	git_buf_puts(path, suffix);
 
-	if (git_buf_oom(path))
-		return GIT_ENOMEM;
-
-	return 0;
+	return git_buf_oom(path) ? -1 : 0;
 }
 
 int git_indexer_write(git_indexer *idx)
@@ -197,26 +193,25 @@ int git_indexer_write(git_indexer *idx)
 	git_buf_sets(&filename, idx->pack->pack_name);
 	git_buf_truncate(&filename, filename.size - strlen("pack"));
 	git_buf_puts(&filename, "idx");
-
 	if (git_buf_oom(&filename))
-		return GIT_ENOMEM;
+		return -1;
 
 	error = git_filebuf_open(&idx->file, filename.ptr, GIT_FILEBUF_HASH_CONTENTS);
-	if (error < GIT_SUCCESS)
+	if (error < 0)
 		goto cleanup;
 
 	/* Write out the header */
 	hdr.idx_signature = htonl(PACK_IDX_SIGNATURE);
 	hdr.idx_version = htonl(2);
 	error = git_filebuf_write(&idx->file, &hdr, sizeof(hdr));
-	if (error < GIT_SUCCESS)
+	if (error < 0)
 		goto cleanup;
 
 	/* Write out the fanout table */
 	for (i = 0; i < 256; ++i) {
 		uint32_t n = htonl(idx->fanout[i]);
 		error = git_filebuf_write(&idx->file, &n, sizeof(n));
-		if (error < GIT_SUCCESS)
+		if (error < 0)
 			goto cleanup;
 	}
 
@@ -225,7 +220,7 @@ int git_indexer_write(git_indexer *idx)
 	git_vector_foreach(&idx->objects, i, entry) {
 		error = git_filebuf_write(&idx->file, &entry->oid, sizeof(git_oid));
 		SHA1_Update(&ctx, &entry->oid, GIT_OID_RAWSZ);
-		if (error < GIT_SUCCESS)
+		if (error < 0)
 			goto cleanup;
 	}
 	SHA1_Final(idx->hash.id, &ctx);
@@ -233,7 +228,7 @@ int git_indexer_write(git_indexer *idx)
 	/* Write out the CRC32 values */
 	git_vector_foreach(&idx->objects, i, entry) {
 		error = git_filebuf_write(&idx->file, &entry->crc, sizeof(uint32_t));
-		if (error < GIT_SUCCESS)
+		if (error < 0)
 			goto cleanup;
 	}
 
@@ -247,7 +242,7 @@ int git_indexer_write(git_indexer *idx)
 			n = htonl(entry->offset);
 
 		error = git_filebuf_write(&idx->file, &n, sizeof(uint32_t));
-		if (error < GIT_SUCCESS)
+		if (error < 0)
 			goto cleanup;
 	}
 
@@ -262,7 +257,7 @@ int git_indexer_write(git_indexer *idx)
 		split[1] = htonl(entry->offset_long & 0xffffffff);
 
 		error = git_filebuf_write(&idx->file, &split, sizeof(uint32_t) * 2);
-		if (error < GIT_SUCCESS)
+		if (error < 0)
 			goto cleanup;
 	}
 
@@ -271,7 +266,7 @@ int git_indexer_write(git_indexer *idx)
 	packfile_hash = git_mwindow_open(&idx->pack->mwf, &w, idx->st.st_size - GIT_OID_RAWSZ, GIT_OID_RAWSZ, &left);
 	git_mwindow_close(&w);
 	if (packfile_hash == NULL) {
-		error = git__rethrow(GIT_ENOMEM, "Failed to open window to packfile hash");
+		error = -1;
 		goto cleanup;
 	}
 
@@ -280,19 +275,21 @@ int git_indexer_write(git_indexer *idx)
 	git_mwindow_close(&w);
 
 	error = git_filebuf_write(&idx->file, &file_hash, sizeof(git_oid));
+	if (error < 0)
+		goto cleanup;
 
 	/* Write out the index sha */
 	error = git_filebuf_hash(&file_hash, &idx->file);
-	if (error < GIT_SUCCESS)
+	if (error < 0)
 		goto cleanup;
 
 	error = git_filebuf_write(&idx->file, &file_hash, sizeof(git_oid));
-	if (error < GIT_SUCCESS)
+	if (error < 0)
 		goto cleanup;
 
 	/* Figure out what the final name should be */
 	error = index_path(&filename, idx);
-	if (error < GIT_SUCCESS)
+	if (error < 0)
 		goto cleanup;
 
 	/* Commit file */
@@ -300,7 +297,7 @@ int git_indexer_write(git_indexer *idx)
 
 cleanup:
 	git_mwindow_free_all(&idx->pack->mwf);
-	if (error < GIT_SUCCESS)
+	if (error < 0)
 		git_filebuf_cleanup(&idx->file);
 	git_buf_free(&filename);
 
@@ -319,8 +316,8 @@ int git_indexer_run(git_indexer *idx, git_indexer_stats *stats)
 
 	mwf = &idx->pack->mwf;
 	error = git_mwindow_file_register(mwf);
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to register mwindow file");
+	if (error < 0)
+		return error;
 
 	stats->total = (unsigned int)idx->nr_objects;
 	stats->processed = processed = 0;
@@ -346,27 +343,26 @@ int git_indexer_run(git_indexer *idx, git_indexer_stats *stats)
 		}
 
 		error = git_packfile_unpack(&obj, idx->pack, &off);
-		if (error < GIT_SUCCESS) {
-			error = git__rethrow(error, "Failed to unpack object");
+		if (error < 0)
 			goto cleanup;
-		}
 
 		/* FIXME: Parse the object instead of hashing it */
 		error = git_odb__hashobj(&oid, &obj);
-		if (error < GIT_SUCCESS) {
-			error = git__rethrow(error, "Failed to hash object");
+		if (error < 0) {
+			giterr_set(GITERR_INVALID, "Failed to hash object");
 			goto cleanup;
 		}
 
 		pentry = git__malloc(sizeof(struct git_pack_entry));
 		if (pentry == NULL) {
-			error = GIT_ENOMEM;
+			error = -1;
 			goto cleanup;
 		}
+
 		git_oid_cpy(&pentry->sha1, &oid);
 		pentry->offset = entry_start;
 		error = git_vector_insert(&idx->pack->cache, pentry);
-		if (error < GIT_SUCCESS)
+		if (error < 0)
 			goto cleanup;
 
 		git_oid_cpy(&entry->oid, &oid);
@@ -375,7 +371,7 @@ int git_indexer_run(git_indexer *idx, git_indexer_stats *stats)
 		entry_size = (size_t)(off - entry_start);
 		packed = git_mwindow_open(mwf, &w, entry_start, entry_size, &left);
 		if (packed == NULL) {
-			error = git__rethrow(error, "Failed to open window to read packed data");
+			error = -1;
 			goto cleanup;
 		}
 		entry->crc = htonl(crc32(entry->crc, packed, (uInt)entry_size));
@@ -383,10 +379,8 @@ int git_indexer_run(git_indexer *idx, git_indexer_stats *stats)
 
 		/* Add the object to the list */
 		error = git_vector_insert(&idx->objects, entry);
-		if (error < GIT_SUCCESS) {
-			error = git__rethrow(error, "Failed to add entry to list");
+		if (error < 0)
 			goto cleanup;
-		}
 
 		for (i = oid.id[0]; i < 256; ++i) {
 			idx->fanout[i]++;
diff --git a/src/iterator.c b/src/iterator.c
index 5cc01cc..cc15b5f 100644
--- a/src/iterator.c
+++ b/src/iterator.c
@@ -395,7 +395,6 @@ static void workdir_iterator__free(git_iterator *self)
 
 static int workdir_iterator__update_entry(workdir_iterator *wi)
 {
-	int error;
 	git_path_with_stat *ps = git_vector_get(&wi->stack->entries, wi->stack->index);
 
 	git_buf_truncate(&wi->path, wi->root_len);
@@ -412,24 +411,18 @@ static int workdir_iterator__update_entry(workdir_iterator *wi)
 	/* if there is an error processing the entry, treat as ignored */
 	wi->is_ignored = 1;
 
-	/* TODO: remove shared code for struct stat conversion with index.c */
-	wi->entry.ctime.seconds = (git_time_t)ps->st.st_ctime;
-	wi->entry.mtime.seconds = (git_time_t)ps->st.st_mtime;
-	wi->entry.dev  = ps->st.st_rdev;
-	wi->entry.ino  = ps->st.st_ino;
+	git_index__init_entry_from_stat(&ps->st, &wi->entry);
+
+	/* need different mode here to keep directories during iteration */
 	wi->entry.mode = git_futils_canonical_mode(ps->st.st_mode);
-	wi->entry.uid  = ps->st.st_uid;
-	wi->entry.gid  = ps->st.st_gid;
-	wi->entry.file_size = ps->st.st_size;
 
 	/* if this is a file type we don't handle, treat as ignored */
 	if (wi->entry.mode == 0)
 		return 0;
 
 	/* okay, we are far enough along to look up real ignore rule */
-	error = git_ignore__lookup(&wi->ignores, wi->entry.path, &wi->is_ignored);
-	if (error < 0)
-		return 0;
+	if (git_ignore__lookup(&wi->ignores, wi->entry.path, &wi->is_ignored) < 0)
+		return 0; /* if error, ignore it and ignore file */
 
 	/* detect submodules */
 	if (S_ISDIR(wi->entry.mode) &&
diff --git a/src/notes.c b/src/notes.c
index 68554c3..05c70c6 100644
--- a/src/notes.c
+++ b/src/notes.c
@@ -21,11 +21,8 @@ static int find_subtree(git_tree **subtree, const git_oid *root,
 	*subtree = NULL;
 
 	error = git_tree_lookup(&tree, repo, root);
-	if (error < GIT_SUCCESS) {
-		if (error == GIT_ENOTFOUND)
-			return error; /* notes tree doesn't exist yet */
-		return git__rethrow(error, "Failed to open notes tree");
-	}
+	if (error < 0)
+		return error;
 
 	for (i=0; i<git_tree_entrycount(tree); i++) {
 		entry = git_tree_entry_byindex(tree, i);
@@ -56,7 +53,7 @@ static int find_subtree(git_tree **subtree, const git_oid *root,
 	}
 
 	*subtree = tree;
-	return GIT_SUCCESS;
+	return 0;
 }
 
 static int find_blob(git_oid *blob, git_tree *tree, const char *target)
@@ -71,7 +68,7 @@ static int find_blob(git_oid *blob, git_tree *tree, const char *target)
 			/* found matching note object - return */
 
 			git_oid_cpy(blob, git_tree_entry_id(entry));
-			return GIT_SUCCESS;
+			return 0;
 		}
 	}
 	return GIT_ENOTFOUND;
@@ -93,18 +90,17 @@ static int note_write(git_oid *out, git_repository *repo,
 
 	if (tree_sha) {
 		error = find_subtree(&tree, tree_sha, repo, target, &fanout);
-		if (error < GIT_SUCCESS)
-			return git__rethrow(error, "Failed to lookup subtree");
+		if (error < 0)
+			return error;
 
 		error = find_blob(&oid, tree, target + fanout);
-		if (error < GIT_SUCCESS && error != GIT_ENOTFOUND) {
-			git_tree_free(tree);
-			return git__throw(GIT_ENOTFOUND, "Failed to read subtree %s", target);
-		}
-
-		if (error == GIT_SUCCESS) {
+		if (error != GIT_ENOTFOUND) {
 			git_tree_free(tree);
-			return git__throw(GIT_EEXISTS, "Note for `%s` exists already", target);
+			if (!error) {
+				giterr_set(GITERR_REPOSITORY, "Note for '%s' exists already", target);
+				error = GIT_EEXISTS;
+			}
+			return error;
 		}
 	}
 
@@ -113,8 +109,8 @@ static int note_write(git_oid *out, git_repository *repo,
 	error = git_treebuilder_create(&tb, tree);
 	git_tree_free(tree);
 
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to create treebuilder");
+	if (error < 0)
+		return error;
 
 	if (!tree_sha)
 		/* no notes tree yet - create fanout */
@@ -122,18 +118,18 @@ static int note_write(git_oid *out, git_repository *repo,
 
 	/* create note object */
 	error = git_blob_create_frombuffer(&oid, repo, note, strlen(note));
-	if (error < GIT_SUCCESS) {
+	if (error < 0) {
 		git_treebuilder_free(tb);
-		return git__rethrow(error, "Failed to create note object");
+		return error;
 	}
 
 	error = git_treebuilder_insert(&entry, tb, target + fanout, &oid, 0100644);
-	if (error < GIT_SUCCESS) {
+	if (error < 0) {
 		/* libgit2 doesn't support object removal (gc) yet */
 		/* we leave an orphaned blob object behind - TODO */
 
 		git_treebuilder_free(tb);
-		return git__rethrow(error, "Failed to insert note object");
+		return error;
 	}
 
 	if (out)
@@ -142,8 +138,8 @@ static int note_write(git_oid *out, git_repository *repo,
 	error = git_treebuilder_write(&oid, repo, tb);
 	git_treebuilder_free(tb);
 
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to write notes tree");
+	if (error < 0)
+		return 0;
 
 	if (!tree_sha) {
 		/* create fanout subtree */
@@ -153,27 +149,28 @@ static int note_write(git_oid *out, git_repository *repo,
 		subtree[2] = '\0';
 
 		error = git_treebuilder_create(&tb, NULL);
-		if (error < GIT_SUCCESS)
-			return git__rethrow(error, "Failed to create treebuilder");
+		if (error < 0)
+			return error;
 
 		error = git_treebuilder_insert(NULL, tb, subtree, &oid, 0040000);
-		if (error < GIT_SUCCESS) {
+		if (error < 0) {
 			git_treebuilder_free(tb);
-			return git__rethrow(error, "Failed to insert note object");
+			return error;
 		}
 
 		error = git_treebuilder_write(&oid, repo, tb);
+
 		git_treebuilder_free(tb);
 
-		if (error < GIT_SUCCESS)
-			return git__rethrow(error, "Failed to write notes tree");
+		if (error < 0)
+			return error;
 	}
 
 	/* create new notes commit */
 
 	error = git_tree_lookup(&tree, repo, &oid);
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to open new notes tree");
+	if (error < 0)
+		return error;
 
 	error = git_commit_create(&oid, repo, notes_ref, author, committer,
 				  NULL, GIT_NOTES_DEFAULT_MSG_ADD,
@@ -181,10 +178,7 @@ static int note_write(git_oid *out, git_repository *repo,
 
 	git_tree_free(tree);
 
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to create new notes commit");
-
-	return GIT_SUCCESS;
+	return error;
 }
 
 static int note_lookup(git_note **out, git_repository *repo,
@@ -197,31 +191,25 @@ static int note_lookup(git_note **out, git_repository *repo,
 	git_note *note;
 
 	error = find_subtree(&tree, tree_sha, repo, target, &fanout);
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to lookup subtree");
+	if (error < 0)
+		return error;
 
 	error = find_blob(&oid, tree, target + fanout);
-	if (error < GIT_SUCCESS) {
-		git_tree_free(tree);
-		return git__throw(GIT_ENOTFOUND, "No note found for object %s",
-				  target);
-	}
+
 	git_tree_free(tree);
+	if (error < 0)
+		return error;
 
 	error = git_blob_lookup(&blob, repo, &oid);
-	if (error < GIT_SUCCESS)
-		return git__throw(GIT_ERROR, "Failed to lookup note object");
+	if (error < 0)
+		return error;
 
 	note = git__malloc(sizeof(git_note));
-	if (note == NULL) {
-		git_blob_free(blob);
-		return GIT_ENOMEM;
-	}
+	GITERR_CHECK_ALLOC(note);
 
 	git_oid_cpy(&note->oid, &oid);
 	note->message = git__strdup(git_blob_rawcontent(blob));
-	if (note->message == NULL)
-		error = GIT_ENOMEM;
+	GITERR_CHECK_ALLOC(note->message);
 
 	*out = note;
 
@@ -240,39 +228,30 @@ static int note_remove(git_repository *repo,
 	git_treebuilder *tb;
 
 	error = find_subtree(&tree, tree_sha, repo, target, &fanout);
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to lookup subtree");
+	if (error < 0)
+		return error;
 
 	error = find_blob(&oid, tree, target + fanout);
-	if (error < GIT_SUCCESS) {
-		git_tree_free(tree);
-		return git__throw(GIT_ENOTFOUND, "No note found for object %s",
-				  target);
-	}
+	if (!error)
+		error = git_treebuilder_create(&tb, tree);
 
-	error = git_treebuilder_create(&tb, tree);
 	git_tree_free(tree);
-
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to create treebuilder");
+	if (error < 0)
+		return error;
 
 	error = git_treebuilder_remove(tb, target + fanout);
-	if (error < GIT_SUCCESS) {
-		git_treebuilder_free(tb);
-		return git__rethrow(error, "Failed to remove entry from notes tree");
-	}
+	if (!error)
+		error = git_treebuilder_write(&oid, repo, tb);
 
-	error = git_treebuilder_write(&oid, repo, tb);
 	git_treebuilder_free(tb);
-
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to write notes tree");
+	if (error < 0)
+		return error;
 
 	/* create new notes commit */
 
 	error = git_tree_lookup(&tree, repo, &oid);
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to open new notes tree");
+	if (error < 0)
+		return error;
 
 	error = git_commit_create(&oid, repo, notes_ref, author, committer,
 				  NULL, GIT_NOTES_DEFAULT_MSG_RM,
@@ -280,9 +259,6 @@ static int note_remove(git_repository *repo,
 
 	git_tree_free(tree);
 
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to create new notes commit");
-
 	return error;
 }
 
@@ -301,8 +277,8 @@ int git_note_read(git_note **out, git_repository *repo,
 		notes_ref = GIT_NOTES_DEFAULT_REF;
 
 	error = git_reference_lookup(&ref, repo, notes_ref);
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to lookup reference `%s`", notes_ref);
+	if (error < 0)
+		return error;
 
 	assert(git_reference_type(ref) == GIT_REF_OID);
 
@@ -311,27 +287,26 @@ int git_note_read(git_note **out, git_repository *repo,
 
 	git_reference_free(ref);
 
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to find notes commit object");
+	if (error < 0)
+		return error;
 
 	sha = git_commit_tree_oid(commit);
 	git_commit_free(commit);
 
 	target = git_oid_allocfmt(oid);
-	if (target == NULL)
-		return GIT_ENOMEM;
+	GITERR_CHECK_ALLOC(target);
 
 	error = note_lookup(out, repo, sha, target);
 
 	git__free(target);
-	return error == GIT_SUCCESS ? GIT_SUCCESS :
-		git__rethrow(error, "Failed to read note");
+	return error;
 }
 
-int git_note_create(git_oid *out, git_repository *repo,
-		    git_signature *author, git_signature *committer,
-		    const char *notes_ref, const git_oid *oid,
-		     const char *note)
+int git_note_create(
+	git_oid *out, git_repository *repo,
+	git_signature *author, git_signature *committer,
+	const char *notes_ref, const git_oid *oid,
+	const char *note)
 {
 	int error, nparents = 0;
 	char *target;
@@ -343,10 +318,10 @@ int git_note_create(git_oid *out, git_repository *repo,
 		notes_ref = GIT_NOTES_DEFAULT_REF;
 
 	error = git_reference_lookup(&ref, repo, notes_ref);
-	if (error < GIT_SUCCESS && error != GIT_ENOTFOUND)
-		return git__rethrow(error, "Failed to lookup reference `%s`", notes_ref);
+	if (error < 0 && error != GIT_ENOTFOUND)
+		return error;
 
-	if (error == GIT_SUCCESS) {
+	if (!error) {
 		assert(git_reference_type(ref) == GIT_REF_OID);
 
 		/* lookup existing notes tree oid */
@@ -355,16 +330,15 @@ int git_note_create(git_oid *out, git_repository *repo,
 		git_reference_free(ref);
 
 		error = git_commit_lookup(&commit, repo, &sha);
-		if (error < GIT_SUCCESS)
-			return git__rethrow(error, "Failed to find notes commit object");
+		if (error < 0)
+			return error;
 
 		git_oid_cpy(&sha, git_commit_tree_oid(commit));
 		nparents++;
 	}
 
 	target = git_oid_allocfmt(oid);
-	if (target == NULL)
-		return GIT_ENOMEM;
+	GITERR_CHECK_ALLOC(target);
 
 	error = note_write(out, repo, author, committer, notes_ref,
 			   note, nparents ? &sha : NULL, target,
@@ -372,8 +346,7 @@ int git_note_create(git_oid *out, git_repository *repo,
 
 	git__free(target);
 	git_commit_free(commit);
-	return error == GIT_SUCCESS ? GIT_SUCCESS :
-		git__rethrow(error, "Failed to write note");
+	return error;
 }
 
 int git_note_remove(git_repository *repo, const char *notes_ref,
@@ -390,8 +363,8 @@ int git_note_remove(git_repository *repo, const char *notes_ref,
 		notes_ref = GIT_NOTES_DEFAULT_REF;
 
 	error = git_reference_lookup(&ref, repo, notes_ref);
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to lookup reference `%s`", notes_ref);
+	if (error < 0)
+		return error;
 
 	assert(git_reference_type(ref) == GIT_REF_OID);
 
@@ -399,22 +372,20 @@ int git_note_remove(git_repository *repo, const char *notes_ref,
 	git_reference_free(ref);
 
 	error = git_commit_lookup(&commit, repo, &sha);
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to find notes commit object");
+	if (error < 0)
+		return error;
 
 	git_oid_cpy(&sha, git_commit_tree_oid(commit));
 
 	target = git_oid_allocfmt(oid);
-	if (target == NULL)
-		return GIT_ENOMEM;
+	GITERR_CHECK_ALLOC(target);
 
 	error = note_remove(repo, author, committer, notes_ref,
 			    &sha, target, 1, &commit);
 
 	git__free(target);
 	git_commit_free(commit);
-	return error == GIT_SUCCESS ? GIT_SUCCESS :
-		git__rethrow(error, "Failed to read note");
+	return error;
 }
 
 const char * git_note_message(git_note *note)
diff --git a/src/odb.c b/src/odb.c
index f68d135..b615cc4 100644
--- a/src/odb.c
+++ b/src/odb.c
@@ -541,6 +541,10 @@ int git_odb_read(git_odb_object **out, git_odb *db, const git_oid *id)
 			error = b->read(&raw.data, &raw.len, &raw.type, b, id);
 	}
 
+	/* TODO: If no backends are configured, this returns GIT_ENOTFOUND but
+	 * will never have called giterr_set().
+	 */
+
 	if (error && error != GIT_EPASSTHROUGH)
 		return error;
 
diff --git a/src/oid.c b/src/oid.c
index a1f0109..4adccfb 100644
--- a/src/oid.c
+++ b/src/oid.c
@@ -13,13 +13,19 @@
 
 static char to_hex[] = "0123456789abcdef";
 
+static int oid_error_invalid(const char *msg)
+{
+	giterr_set(GITERR_INVALID, "Unable to parse OID - %s", msg);
+	return -1;
+}
+
 int git_oid_fromstrn(git_oid *out, const char *str, size_t length)
 {
 	size_t p;
 	int v;
 
 	if (length < 4)
-		return git__throw(GIT_ENOTOID, "Failed to generate sha1. Given string is too short");
+		return oid_error_invalid("input too short");
 
 	if (length > GIT_OID_HEXSZ)
 		length = GIT_OID_HEXSZ;
@@ -29,7 +35,7 @@ int git_oid_fromstrn(git_oid *out, const char *str, size_t length)
 				| git__fromhex(str[p + 1]);
 
 		if (v < 0)
-			return git__throw(GIT_ENOTOID, "Failed to generate sha1. Given string is not a valid sha1 hash");
+			return oid_error_invalid("contains invalid characters");
 
 		out->id[p / 2] = (unsigned char)v;
 	}
@@ -37,7 +43,7 @@ int git_oid_fromstrn(git_oid *out, const char *str, size_t length)
 	if (length % 2) {
 		v = (git__fromhex(str[p + 0]) << 4);
 		if (v < 0)
-			return git__throw(GIT_ENOTOID, "Failed to generate sha1. Given string is not a valid sha1 hash");
+			return oid_error_invalid("contains invalid characters");
 
 		out->id[p / 2] = (unsigned char)v;
 		p += 2;
@@ -45,7 +51,7 @@ int git_oid_fromstrn(git_oid *out, const char *str, size_t length)
 
 	memset(out->id + p / 2, 0, (GIT_OID_HEXSZ - p) / 2);
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 int git_oid_fromstr(git_oid *out, const char *str)
@@ -109,8 +115,9 @@ char *git_oid_to_string(char *out, size_t n, const git_oid *oid)
 	return out;
 }
 
-int git_oid__parse(git_oid *oid, const char **buffer_out,
-		const char *buffer_end, const char *header)
+int git_oid__parse(
+	git_oid *oid, const char **buffer_out,
+	const char *buffer_end, const char *header)
 {
 	const size_t sha_len = GIT_OID_HEXSZ;
 	const size_t header_len = strlen(header);
@@ -118,20 +125,20 @@ int git_oid__parse(git_oid *oid, const char **buffer_out,
 	const char *buffer = *buffer_out;
 
 	if (buffer + (header_len + sha_len + 1) > buffer_end)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse OID. Buffer too small");
+		return oid_error_invalid("input is too short");
 
 	if (memcmp(buffer, header, header_len) != 0)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse OID. Buffer and header do not match");
+		return oid_error_invalid("did not match expected header");
 
 	if (buffer[header_len + sha_len] != '\n')
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse OID. Buffer not terminated correctly");
+		return oid_error_invalid("not terminated correctly");
 
-	if (git_oid_fromstr(oid, buffer + header_len) < GIT_SUCCESS)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse OID. Failed to generate sha1");
+	if (git_oid_fromstr(oid, buffer + header_len) < 0)
+		return -1;
 
 	*buffer_out = buffer + (header_len + sha_len + 1);
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 void git_oid__writebuf(git_buf *buf, const char *header, const git_oid *oid)
@@ -182,12 +189,11 @@ int git_oid_ncmp(const git_oid *oid_a, const git_oid *oid_b, unsigned int len)
 int git_oid_streq(const git_oid *a, const char *str)
 {
 	git_oid id;
-	int error;
 
-	if ((error = git_oid_fromstr(&id, str)) < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to convert '%s' to oid.", str);
+	if (git_oid_fromstr(&id, str) < 0)
+		return -1;
 
-	return git_oid_cmp(a, &id) == 0 ? GIT_SUCCESS : GIT_ERROR;
+	return git_oid_cmp(a, &id) == 0 ? 0 : -1;
 }
 
 int git_oid_iszero(const git_oid *oid_a)
@@ -216,15 +222,14 @@ struct git_oid_shorten {
 static int resize_trie(git_oid_shorten *self, size_t new_size)
 {
 	self->nodes = git__realloc(self->nodes, new_size * sizeof(trie_node));
-	if (self->nodes == NULL)
-		return GIT_ENOMEM;
+	GITERR_CHECK_ALLOC(self->nodes);
 
 	if (new_size > self->size) {
 		memset(&self->nodes[self->size], 0x0, (new_size - self->size) * sizeof(trie_node));
 	}
 
 	self->size = new_size;
-	return GIT_SUCCESS;
+	return 0;
 }
 
 static trie_node *push_leaf(git_oid_shorten *os, node_index idx, int push_at, const char *oid)
@@ -233,7 +238,7 @@ static trie_node *push_leaf(git_oid_shorten *os, node_index idx, int push_at, co
 	node_index idx_leaf;
 
 	if (os->node_count >= os->size) {
-		if (resize_trie(os, os->size * 2) < GIT_SUCCESS)
+		if (resize_trie(os, os->size * 2) < 0)
 			return NULL;
 	}
 
@@ -255,13 +260,11 @@ git_oid_shorten *git_oid_shorten_new(size_t min_length)
 {
 	git_oid_shorten *os;
 
-	os = git__malloc(sizeof(git_oid_shorten));
+	os = git__calloc(1, sizeof(git_oid_shorten));
 	if (os == NULL)
 		return NULL;
 
-	memset(os, 0x0, sizeof(git_oid_shorten));
-
-	if (resize_trie(os, 16) < GIT_SUCCESS) {
+	if (resize_trie(os, 16) < 0) {
 		git__free(os);
 		return NULL;
 	}
@@ -329,7 +332,7 @@ int git_oid_shorten_add(git_oid_shorten *os, const char *text_oid)
 	node_index idx;
 
 	if (os->full)
-		return GIT_ENOMEM;
+		return -1;
 
 	if (text_oid == NULL)
 		return os->min_length;
@@ -341,8 +344,10 @@ int git_oid_shorten_add(git_oid_shorten *os, const char *text_oid)
 		int c = git__fromhex(text_oid[i]);
 		trie_node *node;
 
-		if (c == -1)
-			return git__throw(GIT_ENOTOID, "Failed to shorten OID. Invalid hex value");
+		if (c == -1) {
+			giterr_set(GITERR_INVALID, "Unable to shorten OID - invalid hex value");
+			return -1;
+		}
 
 		node = &os->nodes[idx];
 
@@ -353,13 +358,12 @@ int git_oid_shorten_add(git_oid_shorten *os, const char *text_oid)
 			node->tail = NULL;
 
 			node = push_leaf(os, idx, git__fromhex(tail[0]), &tail[1]);
-			if (node == NULL)
-				return GIT_ENOMEM;
+			GITERR_CHECK_ALLOC(node);
 		}
 
 		if (node->children[c] == 0) {
 			if (push_leaf(os, idx, c, &text_oid[i + 1]) == NULL)
-				return GIT_ENOMEM;
+				return -1;
 			break;
 		}
 
diff --git a/src/reflog.c b/src/reflog.c
index 5352760..e3de0d4 100644
--- a/src/reflog.c
+++ b/src/reflog.c
@@ -16,23 +16,21 @@ static int reflog_init(git_reflog **reflog, git_reference *ref)
 
 	*reflog = NULL;
 
-	log = git__malloc(sizeof(git_reflog));
-	if (log == NULL)
-		return GIT_ENOMEM;
-
-	memset(log, 0x0, sizeof(git_reflog));
+	log = git__calloc(1, sizeof(git_reflog));
+	GITERR_CHECK_ALLOC(log);
 
 	log->ref_name = git__strdup(ref->name);
+	GITERR_CHECK_ALLOC(log->ref_name);
 
 	if (git_vector_init(&log->entries, 0, NULL) < 0) {
 		git__free(log->ref_name);
 		git__free(log);
-		return GIT_ENOMEM;
+		return -1;
 	}
 
 	*reflog = log;
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 static int reflog_write(const char *log_path, const char *oid_old,
@@ -42,9 +40,22 @@ static int reflog_write(const char *log_path, const char *oid_old,
 	int error;
 	git_buf log = GIT_BUF_INIT;
 	git_filebuf fbuf = GIT_FILEBUF_INIT;
+	bool trailing_newline = false;
 
 	assert(log_path && oid_old && oid_new && committer);
 
+	if (msg) {
+		const char *newline = strchr(msg, '\n');
+		if (newline) {
+			if (*(newline + 1) == '\0')
+				trailing_newline = true;
+			else {
+				giterr_set(GITERR_INVALID, "Reflog message cannot contain newline");
+				return -1;
+			}
+		}
+	}
+
 	git_buf_puts(&log, oid_old);
 	git_buf_putc(&log, ' ');
 
@@ -54,68 +65,58 @@ static int reflog_write(const char *log_path, const char *oid_old,
 	git_buf_truncate(&log, log.size - 1); /* drop LF */
 
 	if (msg) {
-		if (strchr(msg, '\n')) {
-			git_buf_free(&log);
-			return git__throw(GIT_ERROR, "Reflog message cannot contain newline");
-		}
-
 		git_buf_putc(&log, '\t');
 		git_buf_puts(&log, msg);
 	}
 
-	git_buf_putc(&log, '\n');
+	if (!trailing_newline)
+		git_buf_putc(&log, '\n');
 
 	if (git_buf_oom(&log)) {
 		git_buf_free(&log);
-		return git__throw(GIT_ENOMEM, "Failed to write reflog. Memory allocation failure");
+		return -1;
 	}
 
-	if ((error = git_filebuf_open(&fbuf, log_path, GIT_FILEBUF_APPEND)) < GIT_SUCCESS) {
-		git_buf_free(&log);
-		return git__rethrow(error, "Failed to write reflog. Cannot open reflog `%s`", log_path);
+	error = git_filebuf_open(&fbuf, log_path, GIT_FILEBUF_APPEND);
+	if (!error) {
+		if ((error = git_filebuf_write(&fbuf, log.ptr, log.size)) < 0)
+			git_filebuf_cleanup(&fbuf);
+		else
+			error = git_filebuf_commit(&fbuf, GIT_REFLOG_FILE_MODE);
 	}
 
-	git_filebuf_write(&fbuf, log.ptr, log.size);
-	error = git_filebuf_commit(&fbuf, GIT_REFLOG_FILE_MODE);
-
 	git_buf_free(&log);
 
-	return error == GIT_SUCCESS ? GIT_SUCCESS : git__rethrow(error, "Failed to write reflog");
+	return error;
 }
 
 static int reflog_parse(git_reflog *log, const char *buf, size_t buf_size)
 {
-	int error = GIT_SUCCESS;
 	const char *ptr;
 	git_reflog_entry *entry;
 
-#define seek_forward(_increase) { \
+#define seek_forward(_increase) do { \
 	if (_increase >= buf_size) { \
-		if (entry->committer) \
-			git__free(entry->committer); \
-		git__free(entry); \
-		return git__throw(GIT_ERROR, "Failed to seek forward. Buffer size exceeded"); \
+		giterr_set(GITERR_INVALID, "Ran out of data while parsing reflog"); \
+		goto fail; \
 	} \
 	buf += _increase; \
 	buf_size -= _increase; \
-}
+	} while (0)
 
 	while (buf_size > GIT_REFLOG_SIZE_MIN) {
 		entry = git__malloc(sizeof(git_reflog_entry));
-		if (entry == NULL)
-			return GIT_ENOMEM;
-		entry->committer = NULL;
+		GITERR_CHECK_ALLOC(entry);
 
-		if (git_oid_fromstrn(&entry->oid_old, buf, GIT_OID_HEXSZ) < GIT_SUCCESS) {
-			git__free(entry);
-			return GIT_ERROR;
-		}
+		entry->committer = git__malloc(sizeof(git_signature));
+		GITERR_CHECK_ALLOC(entry->committer);
+
+		if (git_oid_fromstrn(&entry->oid_old, buf, GIT_OID_HEXSZ) < 0)
+			goto fail;
 		seek_forward(GIT_OID_HEXSZ + 1);
 
-		if (git_oid_fromstrn(&entry->oid_cur, buf, GIT_OID_HEXSZ) < GIT_SUCCESS) {
-			git__free(entry);
-			return GIT_ERROR;
-		}
+		if (git_oid_fromstrn(&entry->oid_cur, buf, GIT_OID_HEXSZ) < 0)
+			goto fail;
 		seek_forward(GIT_OID_HEXSZ + 1);
 
 		ptr = buf;
@@ -124,17 +125,8 @@ static int reflog_parse(git_reflog *log, const char *buf, size_t buf_size)
 		while (*buf && *buf != '\t' && *buf != '\n')
 			seek_forward(1);
 
-		entry->committer = git__malloc(sizeof(git_signature));
-		if (entry->committer == NULL) {
-			git__free(entry);
-			return GIT_ENOMEM;
-		}
-
-		if ((error = git_signature__parse(entry->committer, &ptr, buf + 1, NULL, *buf)) < GIT_SUCCESS) {
-			git__free(entry->committer);
-			git__free(entry);
-			return git__rethrow(error, "Failed to parse reflog. Could not parse signature");
-		}
+		if (git_signature__parse(entry->committer, &ptr, buf + 1, NULL, *buf) < 0)
+			goto fail;
 
 		if (*buf == '\t') {
 			/* We got a message. Read everything till we reach LF. */
@@ -145,19 +137,27 @@ static int reflog_parse(git_reflog *log, const char *buf, size_t buf_size)
 				seek_forward(1);
 
 			entry->msg = git__strndup(ptr, buf - ptr);
+			GITERR_CHECK_ALLOC(entry->msg);
 		} else
 			entry->msg = NULL;
 
 		while (*buf && *buf == '\n' && buf_size > 1)
 			seek_forward(1);
 
-		if ((error = git_vector_insert(&log->entries, entry)) < GIT_SUCCESS)
-			return git__rethrow(error, "Failed to parse reflog. Could not add new entry");
+		if (git_vector_insert(&log->entries, entry) < 0)
+			goto fail;
 	}
 
+	return 0;
+
 #undef seek_forward
 
-	return error == GIT_SUCCESS ? GIT_SUCCESS : git__rethrow(error, "Failed to parse reflog");
+fail:
+	if (entry) {
+		git__free(entry->committer);
+		git__free(entry);
+	}
+	return -1;
 }
 
 void git_reflog_free(git_reflog *reflog)
@@ -188,27 +188,23 @@ int git_reflog_read(git_reflog **reflog, git_reference *ref)
 
 	*reflog = NULL;
 
-	if ((error = reflog_init(&log, ref)) < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to read reflog. Cannot init reflog");
+	if (reflog_init(&log, ref) < 0)
+		return -1;
 
 	error = git_buf_join_n(&log_path, '/', 3,
 		ref->owner->path_repository, GIT_REFLOG_DIR, ref->name);
-	if (error < GIT_SUCCESS)
-		goto cleanup;
 
-	if ((error = git_futils_readbuffer(&log_file, log_path.ptr)) < GIT_SUCCESS) {
-		git__rethrow(error, "Failed to read reflog. Cannot read file `%s`", log_path.ptr);
-		goto cleanup;
-	}
+	if (!error)
+		error = git_futils_readbuffer(&log_file, log_path.ptr);
 
-	if ((error = reflog_parse(log, log_file.ptr, log_file.size)) < GIT_SUCCESS)
-		git__rethrow(error, "Failed to read reflog");
-	else
-		*reflog = log;
+	if (!error)
+		error = reflog_parse(log, log_file.ptr, log_file.size);
 
-cleanup:
-	if (error != GIT_SUCCESS && log != NULL)
+	if (!error)
+		*reflog = log;
+	else
 		git_reflog_free(log);
+
 	git_buf_free(&log_file);
 	git_buf_free(&log_path);
 
@@ -225,16 +221,15 @@ int git_reflog_write(git_reference *ref, const git_oid *oid_old,
 	git_reference *r;
 	const git_oid *oid;
 
-	if ((error = git_reference_resolve(&r, ref)) < GIT_SUCCESS)
-		return git__rethrow(error,
-			"Failed to write reflog. Cannot resolve reference `%s`", ref->name);
+	if ((error = git_reference_resolve(&r, ref)) < 0)
+		return error;
 
 	oid = git_reference_oid(r);
 	if (oid == NULL) {
-		error = git__throw(GIT_ERROR,
+		giterr_set(GITERR_REFERENCE,
 			"Failed to write reflog. Cannot resolve reference `%s`", r->name);
 		git_reference_free(r);
-		return error;
+		return -1;
 	}
 
 	git_oid_to_string(new, GIT_OID_HEXSZ+1, oid);
@@ -243,23 +238,21 @@ int git_reflog_write(git_reference *ref, const git_oid *oid_old,
 
 	error = git_buf_join_n(&log_path, '/', 3,
 		ref->owner->path_repository, GIT_REFLOG_DIR, ref->name);
-	if (error < GIT_SUCCESS)
+	if (error < 0)
 		goto cleanup;
 
 	if (git_path_exists(log_path.ptr) == false) {
 		error = git_futils_mkpath2file(log_path.ptr, GIT_REFLOG_DIR_MODE);
-		if (error < GIT_SUCCESS)
-			git__rethrow(error,
-				"Failed to write reflog. Cannot create reflog directory");
 	} else if (git_path_isfile(log_path.ptr) == false) {
-		error = git__throw(GIT_ERROR,
+		giterr_set(GITERR_REFERENCE,
 			"Failed to write reflog. `%s` is directory", log_path.ptr);
+		error = -1;
 	} else if (oid_old == NULL) {
-		error = git__throw(GIT_ERROR,
+		giterr_set(GITERR_REFERENCE,
 			"Failed to write reflog. Old OID cannot be NULL for existing reference");
+		error = -1;
 	}
-
-	if (error < GIT_SUCCESS)
+	if (error < 0)
 		goto cleanup;
 
 	if (oid_old)
@@ -280,13 +273,13 @@ int git_reflog_rename(git_reference *ref, const char *new_name)
 	git_buf old_path = GIT_BUF_INIT;
 	git_buf new_path = GIT_BUF_INIT;
 
-	if (git_buf_join_n(&old_path, '/', 3, ref->owner->path_repository,
-					   GIT_REFLOG_DIR, ref->name) &&
-		git_buf_join_n(&new_path, '/', 3, ref->owner->path_repository,
-					   GIT_REFLOG_DIR, new_name))
+	if (!git_buf_join_n(&old_path, '/', 3, ref->owner->path_repository,
+			GIT_REFLOG_DIR, ref->name) &&
+		!git_buf_join_n(&new_path, '/', 3, ref->owner->path_repository,
+			GIT_REFLOG_DIR, new_name))
 		error = p_rename(git_buf_cstr(&old_path), git_buf_cstr(&new_path));
 	else
-		error = GIT_ENOMEM;
+		error = -1;
 
 	git_buf_free(&old_path);
 	git_buf_free(&new_path);
@@ -296,13 +289,13 @@ int git_reflog_rename(git_reference *ref, const char *new_name)
 
 int git_reflog_delete(git_reference *ref)
 {
-	int error = GIT_SUCCESS;
+	int error;
 	git_buf path = GIT_BUF_INIT;
 
-	error = git_buf_join_n(&path, '/', 3,
-		ref->owner->path_repository, GIT_REFLOG_DIR, ref->name);
+	error = git_buf_join_n(
+		&path, '/', 3, ref->owner->path_repository, GIT_REFLOG_DIR, ref->name);
 
-	if (error == GIT_SUCCESS && git_path_exists(path.ptr) == true)
+	if (!error && git_path_exists(path.ptr))
 		error = p_unlink(path.ptr);
 
 	git_buf_free(&path);
diff --git a/src/sha1_lookup.c b/src/sha1_lookup.c
index 58d70ae..096da17 100644
--- a/src/sha1_lookup.c
+++ b/src/sha1_lookup.c
@@ -158,7 +158,8 @@ int sha1_entry_pos(const void *table,
 #endif
 
 		if (!(lo <= mi && mi < hi)) {
-			return git__throw(GIT_ERROR, "Assertion failure. Binary search invariant is false");
+			giterr_set(GITERR_INVALID, "Assertion failure. Binary search invariant is false");
+			return -1;
 		}
 
 		mi_key = base + elem_size * mi + key_offset;
diff --git a/src/signature.c b/src/signature.c
index 1b6ba21..87386bc 100644
--- a/src/signature.c
+++ b/src/signature.c
@@ -38,31 +38,38 @@ static const char *skip_trailing_spaces(const char *buffer_start, const char *bu
 	return buffer_end;
 }
 
+static int signature_error(const char *msg)
+{
+	giterr_set(GITERR_INVALID, "Failed to parse signature - %s", msg);
+	return -1;
+}
+
 static int process_trimming(const char *input, char **storage, const char *input_end, int fail_when_empty)
 {
 	const char *left, *right;
 	int trimmed_input_length;
 
+	assert(storage);
+
 	left = skip_leading_spaces(input, input_end);
 	right = skip_trailing_spaces(input, input_end - 1);
 
 	if (right < left) {
 		if (fail_when_empty)
-			return git__throw(GIT_EINVALIDARGS, "Failed to trim. Input is either empty or only contains spaces");
-		else
-			right = left - 1;
+			return signature_error("input is either empty of contains only spaces");
+
+		right = left - 1;
 	}
 
 	trimmed_input_length = right - left + 1;
 
 	*storage = git__malloc(trimmed_input_length + 1);
-	if (*storage == NULL)
-		return GIT_ENOMEM;
+	GITERR_CHECK_ALLOC(*storage);
 
 	memcpy(*storage, left, trimmed_input_length);
 	(*storage)[trimmed_input_length] = 0;
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 int git_signature_new(git_signature **sig_out, const char *name, const char *email, git_time_t time, int offset)
@@ -74,23 +81,14 @@ int git_signature_new(git_signature **sig_out, const char *name, const char *ema
 
 	*sig_out = NULL;
 
-	if ((p = git__malloc(sizeof(git_signature))) == NULL) {
-		error = GIT_ENOMEM;
-		goto cleanup;
-	}
-
-	memset(p, 0x0, sizeof(git_signature));
-
-	error = process_trimming(name, &p->name, name + strlen(name), 1);
-	if (error < GIT_SUCCESS) {
-		git__rethrow(GIT_EINVALIDARGS, "Failed to create signature. 'name' argument is invalid");
-		goto cleanup;
-	}
+	p = git__calloc(1, sizeof(git_signature));
+	GITERR_CHECK_ALLOC(p);
 
-	error = process_trimming(email, &p->email, email + strlen(email), 1);
-	if (error < GIT_SUCCESS) {
-		git__rethrow(GIT_EINVALIDARGS, "Failed to create signature. 'email' argument is invalid");
-		goto cleanup;
+	if ((error = process_trimming(name, &p->name, name + strlen(name), 1)) < 0 ||
+		(error = process_trimming(email, &p->email, email + strlen(email), 1)) < 0)
+	{
+		git_signature_free(p);
+		return error;
 	}
 
 	p->when.time = time;
@@ -98,24 +96,19 @@ int git_signature_new(git_signature **sig_out, const char *name, const char *ema
 
 	*sig_out = p;
 
-	return error;
-
-cleanup:
-	git_signature_free(p);
-	return error;
+	return 0;
 }
 
 git_signature *git_signature_dup(const git_signature *sig)
 {
 	git_signature *new;
-	if (git_signature_new(&new, sig->name, sig->email, sig->when.time, sig->when.offset) < GIT_SUCCESS)
+	if (git_signature_new(&new, sig->name, sig->email, sig->when.time, sig->when.offset) < 0)
 		return NULL;
 	return new;
 }
 
 int git_signature_now(git_signature **sig_out, const char *name, const char *email)
 {
-	int error;
 	time_t now;
 	time_t offset;
 	struct tm *utc_tm, *local_tm;
@@ -148,12 +141,18 @@ int git_signature_now(git_signature **sig_out, const char *name, const char *ema
 	if (local_tm->tm_isdst)
 		offset += 60;
 
-	if ((error = git_signature_new(&sig, name, email, now, (int)offset)) < GIT_SUCCESS)
-		return error;
+	if (git_signature_new(&sig, name, email, now, (int)offset) < 0)
+		return -1;
 
 	*sig_out = sig;
 
-	return error;
+	return 0;
+}
+
+static int timezone_error(const char *msg)
+{
+	giterr_set(GITERR_INVALID, "Failed to parse TZ offset - %s", msg);
+	return -1;
 }
 
 static int parse_timezone_offset(const char *buffer, int *offset_out)
@@ -172,28 +171,28 @@ static int parse_timezone_offset(const char *buffer, int *offset_out)
 	}
 
 	if (offset_start[0] != '-' && offset_start[0] != '+')
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse TZ offset. It doesn't start with '+' or '-'");
+		return timezone_error("does not start with '+' or '-'");
 
 	if (offset_start[1] < '0' || offset_start[1] > '9')
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse TZ offset.");
+		return timezone_error("expected initial digit");
 
 	if (git__strtol32(&dec_offset, offset_start + 1, &offset_end, 10) < GIT_SUCCESS)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse TZ offset. It isn't a number");
+		return timezone_error("not a valid number");
 
 	if (offset_end - offset_start != 5)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse TZ offset. Invalid length");
+		return timezone_error("invalid length");
 
 	if (dec_offset > 1400)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse TZ offset. Value too large");
+		return timezone_error("value too large");
 
 	hours = dec_offset / 100;
 	mins = dec_offset % 100;
 
 	if (hours > 14)	// see http://www.worldtimezone.com/faq.html
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse TZ offset. Hour value too large");
+		return timezone_error("hour value too large");
 
 	if (mins > 59)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse TZ offset. Minute value too large");
+		return timezone_error("minutes value too large");
 
 	offset = (hours * 60) + mins;
 
@@ -202,22 +201,22 @@ static int parse_timezone_offset(const char *buffer, int *offset_out)
 
 	*offset_out = offset;
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 static int process_next_token(const char **buffer_out, char **storage,
 	const char *token_end, const char *right_boundary)
 {
 	int error = process_trimming(*buffer_out, storage, token_end, 0);
-	if (error < GIT_SUCCESS)
+	if (error < 0)
 		return error;
 
 	*buffer_out = token_end + 1;
 
 	if (*buffer_out > right_boundary)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse signature. Signature too short");
+		return signature_error("signature is too short");
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 static const char *scan_for_previous_token(const char *buffer, const char *left_boundary)
@@ -241,17 +240,17 @@ static int parse_time(git_time_t *time_out, const char *buffer)
 	int time;
 	int error;
 
-	if (*buffer == '+' || *buffer == '-')
-		return git__throw(GIT_ERROR, "Failed while parsing time. '%s' rather look like a timezone offset.", buffer);
+	if (*buffer == '+' || *buffer == '-') {
+		giterr_set(GITERR_INVALID, "Failed while parsing time. '%s' actually looks like a timezone offset.", buffer);
+		return -1;
+	}
 
 	error = git__strtol32(&time, buffer, &buffer, 10);
 
-	if (error < GIT_SUCCESS)
-		return error;
+	if (!error)
+		*time_out = (git_time_t)time;
 
-	*time_out = (git_time_t)time;
-
-	return GIT_SUCCESS;
+	return error;
 }
 
 int git_signature__parse(git_signature *sig, const char **buffer_out,
@@ -259,40 +258,40 @@ int git_signature__parse(git_signature *sig, const char **buffer_out,
 {
 	const char *buffer = *buffer_out;
 	const char *line_end, *name_end, *email_end, *tz_start, *time_start;
-	int error = GIT_SUCCESS;
+	int error = 0;
 
 	memset(sig, 0x0, sizeof(git_signature));
 
 	if ((line_end = memchr(buffer, ender, buffer_end - buffer)) == NULL)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse signature. No newline given");
+		return signature_error("no newline given");
 
 	if (header) {
 		const size_t header_len = strlen(header);
 
 		if (memcmp(buffer, header, header_len) != 0)
-			return git__throw(GIT_EOBJCORRUPTED, "Failed to parse signature. Expected prefix '%s' doesn't match actual", header);
+			return signature_error("expected prefix doesn't match actual");
 
 		buffer += header_len;
 	}
 
 	if (buffer > line_end)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse signature. Signature too short");
+		return signature_error("signature too short");
 
 	if ((name_end = strchr(buffer, '<')) == NULL)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse signature. Cannot find '<' in signature");
+		return signature_error("character '<' not allowed in signature");
 
 	if ((email_end = strchr(name_end, '>')) == NULL)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse signature. Cannot find '>' in signature");
+		return signature_error("character '>' not allowed in signature");
 
 	if (email_end < name_end)
-		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse signature. Malformed e-mail");
+		return signature_error("malformed e-mail");
 
 	error = process_next_token(&buffer, &sig->name, name_end, line_end);
-	if (error < GIT_SUCCESS)
+	if (error < 0)
 		return error;
 
 	error = process_next_token(&buffer, &sig->email, email_end, line_end);
-	if (error < GIT_SUCCESS)
+	if (error < 0)
 		return error;
 
 	tz_start = scan_for_previous_token(line_end - 1, buffer);
@@ -301,19 +300,19 @@ int git_signature__parse(git_signature *sig, const char **buffer_out,
 		goto clean_exit;	/* No timezone nor date */
 
 	time_start = scan_for_previous_token(tz_start - 1, buffer);
-	if (time_start == NULL || parse_time(&sig->when.time, time_start) < GIT_SUCCESS) {
+	if (time_start == NULL || parse_time(&sig->when.time, time_start) < 0) {
 		/* The tz_start might point at the time */
 		parse_time(&sig->when.time, tz_start);
 		goto clean_exit;
 	}
 
-	if (parse_timezone_offset(tz_start, &sig->when.offset) < GIT_SUCCESS) {
+	if (parse_timezone_offset(tz_start, &sig->when.offset) < 0) {
 		sig->when.time = 0; /* Bogus timezone, we reset the time */
 	}
 
 clean_exit:
 	*buffer_out = line_end + 1;
-	return GIT_SUCCESS;
+	return 0;
 }
 
 void git_signature__writebuf(git_buf *buf, const char *header, const git_signature *sig)
diff --git a/src/util.c b/src/util.c
index 679917e..d0ad474 100644
--- a/src/util.c
+++ b/src/util.c
@@ -112,34 +112,40 @@ int git__strtol64(int64_t *result, const char *nptr, const char **endptr, int ba
 	}
 
 Return:
-	if (ndig == 0)
-		return git__throw(GIT_ENOTNUM, "Failed to convert string to long. Not a number");
+	if (ndig == 0) {
+		giterr_set(GITERR_INVALID, "Failed to convert string to long. Not a number");
+		return -1;
+	}
 
 	if (endptr)
 		*endptr = p;
 
-	if (ovfl)
-		return git__throw(GIT_EOVERFLOW, "Failed to convert string to long. Overflow error");
+	if (ovfl) {
+		giterr_set(GITERR_INVALID, "Failed to convert string to long. Overflow error");
+		return -1;
+	}
 
 	*result = neg ? -n : n;
-	return GIT_SUCCESS;
+	return 0;
 }
 
 int git__strtol32(int32_t *result, const char *nptr, const char **endptr, int base)
 {
-	int error = GIT_SUCCESS;
+	int error;
 	int32_t tmp_int;
 	int64_t tmp_long;
 
-	if ((error = git__strtol64(&tmp_long, nptr, endptr, base)) < GIT_SUCCESS)
+	if ((error = git__strtol64(&tmp_long, nptr, endptr, base)) < 0)
 		return error;
 
 	tmp_int = tmp_long & 0xFFFFFFFF;
-	if (tmp_int != tmp_long)
-		return git__throw(GIT_EOVERFLOW, "Failed to convert. '%s' is too large", nptr);
+	if (tmp_int != tmp_long) {
+		giterr_set(GITERR_INVALID, "Failed to convert. '%s' is too large", nptr);
+		return -1;
+	}
 
 	*result = tmp_int;
-	
+
 	return error;
 }
 
diff --git a/tests-clar/clar b/tests-clar/clar
index a718a00..506bde3 100755
--- a/tests-clar/clar
+++ b/tests-clar/clar
@@ -87,7 +87,7 @@ class ClarTestBuilder:
 
         if not self.suite_data:
             raise RuntimeError(
-                'No tests found under "%s"' % folder_name)
+                'No tests found under "%s"' % path)
 
     def render(self):
         main_file = os.path.join(self.path, 'clar_main.c')
@@ -297,13 +297,13 @@ static const struct clar_func _clar_cb_${suite_name}[] = {
 
 
 CLAR_FILES = {
-"clar.c" : r"""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""",
+"clar.c" : r"""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""",
 "clar_print_default.c" : r"""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""",
 "clar_print_tap.c" : r"""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""",
 "clar_sandbox.c" : r"""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""",
 "clar_fixtures.c" : r"""eJyFUV1LwzAUfW5+xZU9rLUVJ4ggZQ9DFAUfZEwQSglZmrBAl5Qkk6n43236tWbKfMvNOfecc+81llhBgSppLNAN0XCOuNjbnWa4InYTjpE1MSzxuD1Vki2L0BcKTKfn0EYgu57d3uRpjYhPhi1opSwumUwRCvo3zMFYXT9C5xA5stWSVh9hI5FAa+wUFG//osgJCA5tmQ1SF3CVw9kcppfTCAWBj8ZxDg3UN4/zZ7MaHBrHSBw7vpcJ4mGS5Ijtai9qnannNqk1q7myXU+KvhGaCF4wDnfPiyV+eHpbvS7v8cti9YjGq6Yl7lzCkxfo1L0j/lJOwOtrUrwrUcDBBRsii7Xan3bjBlNVL2WUzuMkgGlJdLuIP21oyYjcVf/a6G3ozXTQPRqmsZkwWQiOfgAVGffP""",
 "clar_fs.c" : r"""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""",
-"clar.h" : r"""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"""
+"clar.h" : r"""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"""
 }
 if __name__ == '__main__':
     main()
diff --git a/tests-clar/core/buffer.c b/tests-clar/core/buffer.c
index 870525b..4ba7b66 100644
--- a/tests-clar/core/buffer.c
+++ b/tests-clar/core/buffer.c
@@ -544,3 +544,20 @@ void test_core_buffer__9(void)
 
 	git_buf_free(&buf);
 }
+
+void test_core_buffer__10(void)
+{
+	git_buf a = GIT_BUF_INIT;
+
+	cl_git_pass(git_buf_join_n(&a, '/', 1, "test"));
+	cl_assert_strequal(a.ptr, "test");
+	cl_git_pass(git_buf_join_n(&a, '/', 1, "string"));
+	cl_assert_strequal(a.ptr, "test/string");
+	git_buf_clear(&a);
+	cl_git_pass(git_buf_join_n(&a, '/', 3, "test", "string", "join"));
+	cl_assert_strequal(a.ptr, "test/string/join");
+	cl_git_pass(git_buf_join_n(&a, '/', 2, a.ptr, "more"));
+	cl_assert_strequal(a.ptr, "test/string/join/test/string/join/more");
+
+	git_buf_free(&a);
+}
diff --git a/tests-clar/core/oid.c b/tests-clar/core/oid.c
index 60361c4..c897139 100644
--- a/tests-clar/core/oid.c
+++ b/tests-clar/core/oid.c
@@ -10,9 +10,9 @@ void test_core_oid__initialize(void)
 
 void test_core_oid__streq(void)
 {
-	cl_assert(git_oid_streq(&id, str_oid) == GIT_SUCCESS);
-	cl_assert(git_oid_streq(&id, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef") == GIT_ERROR);
+	cl_assert(git_oid_streq(&id, str_oid) == 0);
+	cl_assert(git_oid_streq(&id, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef") == -1);
 
-	cl_assert(git_oid_streq(&id, "deadbeef") == GIT_ENOTOID);
-	cl_assert(git_oid_streq(&id, "I'm not an oid.... :)") == GIT_ENOTOID);
+	cl_assert(git_oid_streq(&id, "deadbeef") == -1);
+	cl_assert(git_oid_streq(&id, "I'm not an oid.... :)") == -1);
 }