thodg/libgit2

diff --git a/include/git2/blame.h b/include/git2/blame.h
index 73bcc5b..b98c6f0 100644
--- a/include/git2/blame.h
+++ b/include/git2/blame.h
@@ -183,7 +183,7 @@ GIT_EXTERN(int) git_blame_buffer(
 		git_blame **out,
 		git_blame *reference,
 		const char *buffer,
-		uint32_t buffer_len);
+		size_t buffer_len);
 
 /**
  * Free memory allocated by git_blame_file or git_blame_buffer.
diff --git a/include/git2/blob.h b/include/git2/blob.h
index 6ba5e9f..ac4d843 100644
--- a/include/git2/blob.h
+++ b/include/git2/blob.h
@@ -196,13 +196,14 @@ GIT_EXTERN(int) git_blob_create_fromchunks(
 /**
  * Write an in-memory buffer to the ODB as a blob
  *
- * @param oid return the oid of the written blob
+ * @param id return the id of the written blob
  * @param repo repository where to blob will be written
  * @param buffer data to be written into the blob
  * @param len length of the data
  * @return 0 or an error code
  */
-GIT_EXTERN(int) git_blob_create_frombuffer(git_oid *oid, git_repository *repo, const void *buffer, size_t len);
+GIT_EXTERN(int) git_blob_create_frombuffer(
+	git_oid *id, git_repository *repo, const void *buffer, size_t len);
 
 /**
  * Determine if the blob content is most certainly binary or not.
diff --git a/include/git2/submodule.h b/include/git2/submodule.h
index af08ba6..d724326 100644
--- a/include/git2/submodule.h
+++ b/include/git2/submodule.h
@@ -106,19 +106,6 @@ typedef enum {
 	GIT_SUBMODULE_STATUS_WD_UNTRACKED)) != 0)
 
 /**
- * Options for submodule recurse.
- *
- * * GIT_SUBMODULE_RECURSE_NO   - do no recurse into submodules
- * * GIT_SUBMODULE_RECURSE_YES  - recurse into submodules
- * * GIT_SUBMODULE_RECURSE_ONDEMAND - recurse into submodules only when commit not already in local clone
- */
-typedef enum {
-	GIT_SUBMODULE_RECURSE_NO = 0,
-	GIT_SUBMODULE_RECURSE_YES = 1,
-	GIT_SUBMODULE_RECURSE_ONDEMAND = 2,
-} git_submodule_recurse_t;
-
-/**
  * Lookup submodule information by name or path.
  *
  * Given either the submodule name or path (they are usually the same), this
diff --git a/include/git2/types.h b/include/git2/types.h
index d88815d..2229f6b 100644
--- a/include/git2/types.h
+++ b/include/git2/types.h
@@ -323,6 +323,25 @@ typedef enum {
 	GIT_SUBMODULE_IGNORE_DEFAULT   = 0
 } git_submodule_ignore_t;
 
+/**
+ * Options for submodule recurse.
+ *
+ * Represent the value of `submodule.$name.fetchRecurseSubmodules`
+ *
+ * * GIT_SUBMODULE_RECURSE_RESET - reset to the on-disk value
+ * * GIT_SUBMODULE_RECURSE_NO    - do no recurse into submodules
+ * * GIT_SUBMODULE_RECURSE_YES   - recurse into submodules
+ * * GIT_SUBMODULE_RECURSE_ONDEMAND - recurse into submodules only when
+ *                                    commit not already in local clone
+ */
+typedef enum {
+	GIT_SUBMODULE_RECURSE_RESET = -1,
+
+	GIT_SUBMODULE_RECURSE_NO = 0,
+	GIT_SUBMODULE_RECURSE_YES = 1,
+	GIT_SUBMODULE_RECURSE_ONDEMAND = 2,
+} git_submodule_recurse_t;
+
 /** @} */
 GIT_END_DECL
 
diff --git a/src/attr.c b/src/attr.c
index ff4446e..15ed5c9 100644
--- a/src/attr.c
+++ b/src/attr.c
@@ -49,6 +49,8 @@ int git_attr_get(
 	git_attr_name attr;
 	git_attr_rule *rule;
 
+	assert(value && repo && name);
+
 	*value = NULL;
 
 	if (git_attr_path__init(&path, pathname, git_repository_workdir(repo)) < 0)
@@ -103,6 +105,11 @@ int git_attr_get_many(
 	attr_get_many_info *info = NULL;
 	size_t num_found = 0;
 
+	if (!num_attr)
+		return 0;
+
+	assert(values && repo && names);
+
 	if (git_attr_path__init(&path, pathname, git_repository_workdir(repo)) < 0)
 		return -1;
 
@@ -169,6 +176,8 @@ int git_attr_foreach(
 	git_attr_assignment *assign;
 	git_strmap *seen = NULL;
 
+	assert(repo && callback);
+
 	if (git_attr_path__init(&path, pathname, git_repository_workdir(repo)) < 0)
 		return -1;
 
diff --git a/src/blame.c b/src/blame.c
index 0f2d906..71bc460 100644
--- a/src/blame.c
+++ b/src/blame.c
@@ -450,7 +450,7 @@ int git_blame_buffer(
 		git_blame **out,
 		git_blame *reference,
 		const char *buffer,
-		uint32_t buffer_len)
+		size_t buffer_len)
 {
 	git_blame *blame;
 	git_diff_options diffopts = GIT_DIFF_OPTIONS_INIT;
diff --git a/src/blob.c b/src/blob.c
index 2e924f3..faf8a4a 100644
--- a/src/blob.c
+++ b/src/blob.c
@@ -50,25 +50,28 @@ int git_blob__parse(void *blob, git_odb_object *odb_obj)
 	return 0;
 }
 
-int git_blob_create_frombuffer(git_oid *oid, git_repository *repo, const void *buffer, size_t len)
+int git_blob_create_frombuffer(
+	git_oid *id, git_repository *repo, const void *buffer, size_t len)
 {
 	int error;
 	git_odb *odb;
 	git_odb_stream *stream;
 
+	assert(id && repo);
+
 	if ((error = git_repository_odb__weakptr(&odb, repo)) < 0 ||
 		(error = git_odb_open_wstream(&stream, odb, len, GIT_OBJ_BLOB)) < 0)
 		return error;
 
 	if ((error = git_odb_stream_write(stream, buffer, len)) == 0)
-		error = git_odb_stream_finalize_write(oid, stream);
+		error = git_odb_stream_finalize_write(id, stream);
 
 	git_odb_stream_free(stream);
 	return error;
 }
 
 static int write_file_stream(
-	git_oid *oid, git_odb *odb, const char *path, git_off_t file_size)
+	git_oid *id, git_odb *odb, const char *path, git_off_t file_size)
 {
 	int fd, error;
 	char buffer[4096];
@@ -97,14 +100,14 @@ static int write_file_stream(
 	}
 
 	if (!error)
-		error = git_odb_stream_finalize_write(oid, stream);
+		error = git_odb_stream_finalize_write(id, stream);
 
 	git_odb_stream_free(stream);
 	return error;
 }
 
 static int write_file_filtered(
-	git_oid *oid,
+	git_oid *id,
 	git_off_t *size,
 	git_odb *odb,
 	const char *full_path,
@@ -119,7 +122,7 @@ static int write_file_filtered(
 	if (!error) {
 		*size = tgt.size;
 
-		error = git_odb_write(oid, odb, tgt.ptr, tgt.size, GIT_OBJ_BLOB);
+		error = git_odb_write(id, odb, tgt.ptr, tgt.size, GIT_OBJ_BLOB);
 	}
 
 	git_buf_free(&tgt);
@@ -127,7 +130,7 @@ static int write_file_filtered(
 }
 
 static int write_symlink(
-	git_oid *oid, git_odb *odb, const char *path, size_t link_size)
+	git_oid *id, git_odb *odb, const char *path, size_t link_size)
 {
 	char *link_data;
 	ssize_t read_len;
@@ -143,13 +146,13 @@ static int write_symlink(
 		return -1;
 	}
 
-	error = git_odb_write(oid, odb, (void *)link_data, link_size, GIT_OBJ_BLOB);
+	error = git_odb_write(id, odb, (void *)link_data, link_size, GIT_OBJ_BLOB);
 	git__free(link_data);
 	return error;
 }
 
 int git_blob__create_from_paths(
-	git_oid *oid,
+	git_oid *id,
 	struct stat *out_st,
 	git_repository *repo,
 	const char *content_path,
@@ -188,7 +191,7 @@ int git_blob__create_from_paths(
 	mode = hint_mode ? hint_mode : st.st_mode;
 
 	if (S_ISLNK(mode)) {
-		error = write_symlink(oid, odb, content_path, (size_t)size);
+		error = write_symlink(id, odb, content_path, (size_t)size);
 	} else {
 		git_filter_list *fl = NULL;
 
@@ -202,10 +205,10 @@ int git_blob__create_from_paths(
 		else if (fl == NULL)
 			/* No filters need to be applied to the document: we can stream
 			 * directly from disk */
-			error = write_file_stream(oid, odb, content_path, size);
+			error = write_file_stream(id, odb, content_path, size);
 		else {
 			/* We need to apply one or more filters */
-			error = write_file_filtered(oid, &size, odb, content_path, fl);
+			error = write_file_filtered(id, &size, odb, content_path, fl);
 
 			git_filter_list_free(fl);
 		}
@@ -233,13 +236,13 @@ done:
 }
 
 int git_blob_create_fromworkdir(
-	git_oid *oid, git_repository *repo, const char *path)
+	git_oid *id, git_repository *repo, const char *path)
 {
-	return git_blob__create_from_paths(oid, NULL, repo, NULL, path, 0, true);
+	return git_blob__create_from_paths(id, NULL, repo, NULL, path, 0, true);
 }
 
 int git_blob_create_fromdisk(
-	git_oid *oid, git_repository *repo, const char *path)
+	git_oid *id, git_repository *repo, const char *path)
 {
 	int error;
 	git_buf full_path = GIT_BUF_INIT;
@@ -257,7 +260,7 @@ int git_blob_create_fromdisk(
 		hintpath += strlen(workdir);
 
 	error = git_blob__create_from_paths(
-		oid, NULL, repo, git_buf_cstr(&full_path), hintpath, 0, true);
+		id, NULL, repo, git_buf_cstr(&full_path), hintpath, 0, true);
 
 	git_buf_free(&full_path);
 	return error;
@@ -266,7 +269,7 @@ int git_blob_create_fromdisk(
 #define BUFFER_SIZE 4096
 
 int git_blob_create_fromchunks(
-	git_oid *oid,
+	git_oid *id,
 	git_repository *repo,
 	const char *hintpath,
 	int (*source_cb)(char *content, size_t max_length, void *payload),
@@ -277,7 +280,7 @@ int git_blob_create_fromchunks(
 	git_filebuf file = GIT_FILEBUF_INIT;
 	git_buf path = GIT_BUF_INIT;
 
-	assert(oid && repo && source_cb);
+	assert(id && repo && source_cb);
 
 	if ((error = git_buf_joinpath(
 			&path, git_repository_path(repo), GIT_OBJECTS_DIR "streamed")) < 0)
@@ -313,7 +316,7 @@ int git_blob_create_fromchunks(
 		goto cleanup;
 
 	error = git_blob__create_from_paths(
-		oid, NULL, repo, file.path_lock, hintpath, 0, hintpath != NULL);
+		id, NULL, repo, file.path_lock, hintpath, 0, hintpath != NULL);
 
 cleanup:
 	git_buf_free(&path);
diff --git a/src/branch.c b/src/branch.c
index a1a04b2..d0dc21b 100644
--- a/src/branch.c
+++ b/src/branch.c
@@ -21,27 +21,22 @@ static int retrieve_branch_reference(
 	const char *branch_name,
 	int is_remote)
 {
-	git_reference *branch;
-	int error = -1;
+	git_reference *branch = NULL;
+	int error = 0;
 	char *prefix;
 	git_buf ref_name = GIT_BUF_INIT;
 
-	*branch_reference_out = NULL;
-
 	prefix = is_remote ? GIT_REFS_REMOTES_DIR : GIT_REFS_HEADS_DIR;
 
-	if (git_buf_joinpath(&ref_name, prefix, branch_name) < 0)
-		goto cleanup;
+	if ((error = git_buf_joinpath(&ref_name, prefix, branch_name)) < 0)
+		/* OOM */;
+	else if ((error = git_reference_lookup(&branch, repo, ref_name.ptr)) < 0)
+		giterr_set(
+			GITERR_REFERENCE, "Cannot locate %s branch '%s'",
+			is_remote ? "remote-tracking" : "local", branch_name);
 
-	if ((error = git_reference_lookup(&branch, repo, ref_name.ptr)) < 0) {
-		giterr_set(GITERR_REFERENCE,
-			"Cannot locate %s branch '%s'.", is_remote ? "remote-tracking" : "local", branch_name);
-		goto cleanup;
-	}
+	*branch_reference_out = branch; /* will be NULL on error */
 
-	*branch_reference_out = branch;
-
-cleanup:
 	git_buf_free(&ref_name);
 	return error;
 }
@@ -63,21 +58,19 @@ int git_branch_create(
 {
 	git_reference *branch = NULL;
 	git_buf canonical_branch_name = GIT_BUF_INIT;
-	int error = -1;
+	int error = 0;
 
 	assert(branch_name && commit && ref_out);
 	assert(git_object_owner((const git_object *)commit) == repository);
 
-	if (git_buf_joinpath(&canonical_branch_name, GIT_REFS_HEADS_DIR, branch_name) < 0)
-		goto cleanup;
-
-	error = git_reference_create(&branch, repository,
-		git_buf_cstr(&canonical_branch_name), git_commit_id(commit), force, NULL, NULL);
+	if (!(error = git_buf_joinpath(
+			&canonical_branch_name, GIT_REFS_HEADS_DIR, branch_name)))
+		error = git_reference_create(
+			&branch, repository, git_buf_cstr(&canonical_branch_name),
+			git_commit_id(commit), force, NULL, NULL);
 
-	if (!error)
-		*ref_out = branch;
+	*ref_out = branch;
 
-cleanup:
 	git_buf_free(&canonical_branch_name);
 	return error;
 }
diff --git a/src/indexer.c b/src/indexer.c
index 9b60ef4..346870f 100644
--- a/src/indexer.c
+++ b/src/indexer.c
@@ -659,7 +659,7 @@ static int inject_object(git_indexer *idx, git_oid *id)
 	hdr_len = git_packfile__object_header(hdr, len, git_odb_object_type(obj));
 	git_filebuf_write(&idx->pack_file, hdr, hdr_len);
 	idx->pack->mwf.size += hdr_len;
-	entry->crc = crc32(entry->crc, hdr, hdr_len);
+	entry->crc = crc32(entry->crc, hdr, (uInt)hdr_len);
 
 	if ((error = git_zstream_deflatebuf(&buf, data, len)) < 0)
 		goto cleanup;
diff --git a/src/pack-objects.c b/src/pack-objects.c
index 1774b07..8b65ac2 100644
--- a/src/pack-objects.c
+++ b/src/pack-objects.c
@@ -291,7 +291,6 @@ static int write_object(
 	void *delta_data = NULL;
 	void *data;
 	size_t hdr_len, zbuf_len = COMPRESS_BUFLEN, data_len;
-	ssize_t written;
 	int error;
 
 	if (po->delta) {
@@ -337,19 +336,15 @@ static int write_object(
 		GITERR_CHECK_ALLOC(zbuf);
 
 		git_zstream_reset(&pb->zstream);
+		git_zstream_set_input(&pb->zstream, data, data_len);
 
-		while ((written = git_zstream_deflate(zbuf, zbuf_len, &pb->zstream, data, data_len)) > 0) {
-			if ((error = write_cb(zbuf, written, cb_data)) < 0 ||
-				(error = git_hash_update(&pb->ctx, zbuf, written)) < 0)
+		while (!git_zstream_done(&pb->zstream)) {
+			if ((error = git_zstream_get_output(zbuf, &zbuf_len, &pb->zstream)) < 0 ||
+				(error = write_cb(zbuf, zbuf_len, cb_data)) < 0 ||
+				(error = git_hash_update(&pb->ctx, zbuf, zbuf_len)) < 0)
 				goto done;
 
-			data = (char *)data + written;
-			data_len -= written;
-		}
-
-		if (written < 0) {
-			error = written;
-			goto done;
+			zbuf_len = COMPRESS_BUFLEN; /* reuse buffer */
 		}
 
 		if (po->delta)
diff --git a/src/submodule.c b/src/submodule.c
index 720681d..2388bd1 100644
--- a/src/submodule.c
+++ b/src/submodule.c
@@ -498,6 +498,7 @@ int git_submodule_save(git_submodule *submodule)
 
 	submodule->ignore_default = submodule->ignore;
 	submodule->update_default = submodule->update;
+	submodule->fetch_recurse_default = submodule->fetch_recurse;
 	submodule->flags |= GIT_SUBMODULE_STATUS_IN_CONFIG;
 
 cleanup:
@@ -650,6 +651,9 @@ git_submodule_recurse_t git_submodule_set_fetch_recurse_submodules(
 
 	assert(submodule);
 
+	if (fetch_recurse_submodules == GIT_SUBMODULE_RECURSE_RESET)
+		fetch_recurse_submodules = submodule->fetch_recurse_default;
+
 	old = submodule->fetch_recurse;
 	submodule->fetch_recurse = fetch_recurse_submodules;
 	return old;
@@ -1000,7 +1004,7 @@ static git_submodule *submodule_alloc(git_repository *repo, const char *name)
 	GIT_REFCOUNT_INC(sm);
 	sm->ignore = sm->ignore_default = GIT_SUBMODULE_IGNORE_NONE;
 	sm->update = sm->update_default = GIT_SUBMODULE_UPDATE_CHECKOUT;
-	sm->fetch_recurse = GIT_SUBMODULE_RECURSE_YES;
+	sm->fetch_recurse = sm->fetch_recurse_default = GIT_SUBMODULE_RECURSE_NO;
 	sm->repo   = repo;
 	sm->branch = NULL;
 
@@ -1218,6 +1222,7 @@ static int submodule_load_from_config(
 	else if (strcasecmp(property, "fetchRecurseSubmodules") == 0) {
 		if (git_submodule_parse_recurse(&sm->fetch_recurse, value) < 0)
 			return -1;
+		sm->fetch_recurse_default = sm->fetch_recurse;
 	}
 	else if (strcasecmp(property, "ignore") == 0) {
 		if ((error = git_submodule_parse_ignore(&sm->ignore, value)) < 0)
diff --git a/src/submodule.h b/src/submodule.h
index 94748ac..5e532e1 100644
--- a/src/submodule.h
+++ b/src/submodule.h
@@ -60,7 +60,9 @@
  * - `update_default` is the update value from the config
  * - `ignore` is a git_submodule_ignore_t value - see gitmodules(5) ignore.
  * - `ignore_default` is the ignore value from the config
- * - `fetch_recurse` is 0 or 1 - see gitmodules(5) fetchRecurseSubmodules.
+ * - `fetch_recurse` is a git_submodule_recurse_t value - see gitmodules(5)
+ *    fetchRecurseSubmodules.
+ * - `fetch_recurse_default` is the recurse value from the config
  *
  * - `repo` is the parent repository that contains this submodule.
  * - `flags` after for internal use, tracking where this submodule has been
@@ -87,6 +89,7 @@ struct git_submodule {
 	git_submodule_ignore_t ignore;
 	git_submodule_ignore_t ignore_default;
 	git_submodule_recurse_t fetch_recurse;
+	git_submodule_recurse_t fetch_recurse_default;
 
 	/* internal information */
 	git_repository *repo;
diff --git a/src/userdiff.h b/src/userdiff.h
index 9318b54..7eb0952 100644
--- a/src/userdiff.h
+++ b/src/userdiff.h
@@ -193,9 +193,9 @@ PATTERNS("php",
 	 "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"),
 
 PATTERNS("javascript",
-	 "^[ \t]*(function[ \t][a-zA-Z_][^\{]*)\n"
-	 "^[ \t]*(var[ \t]+[a-zA-Z_][a-zA-Z0-9_]*[ \t]*=[ \t]*function[ \t\(][^\{]*)\n"
-	 "^[ \t]*([a-zA-Z_][a-zA-Z0-9_]*[ \t]*:[ \t]*function[ \t\(][^\{]*)",
+	 "^[ \t]*(function[ \t][a-zA-Z_][^\\{]*)\n"
+	 "^[ \t]*(var[ \t]+[a-zA-Z_][a-zA-Z0-9_]*[ \t]*=[ \t]*function[ \t\\(][^\\{]*)\n"
+	 "^[ \t]*([a-zA-Z_][a-zA-Z0-9_]*[ \t]*:[ \t]*function[ \t\\(][^\\{]*)",
 	 /* -- */
 	 "[a-zA-Z_][a-zA-Z0-9_]*"
 	 "|[-+0-9.e]+[fFlL]?|0[xX]?[0-9a-fA-F]+[lL]?"
diff --git a/src/zstream.c b/src/zstream.c
index 0bca72f..85fa2e0 100644
--- a/src/zstream.c
+++ b/src/zstream.c
@@ -10,14 +10,18 @@
 #include "zstream.h"
 #include "buffer.h"
 
-#define BUFFER_SIZE (1024 * 1024)
+#define ZSTREAM_BUFFER_SIZE (1024 * 1024)
+#define ZSTREAM_BUFFER_MIN_EXTRA 8
 
-static int zstream_seterr(int zerr, git_zstream *zstream)
+static int zstream_seterr(git_zstream *zs)
 {
-	if (zerr == Z_MEM_ERROR)
+	if (zs->zerr == Z_OK || zs->zerr == Z_STREAM_END)
+		return 0;
+
+	if (zs->zerr == Z_MEM_ERROR)
 		giterr_set_oom();
-	else if (zstream->msg)
-		giterr_set(GITERR_ZLIB, zstream->msg);
+	else if (zs->z.msg)
+		giterr_set(GITERR_ZLIB, zs->z.msg);
 	else
 		giterr_set(GITERR_ZLIB, "Unknown compression error");
 
@@ -26,69 +30,127 @@ static int zstream_seterr(int zerr, git_zstream *zstream)
 
 int git_zstream_init(git_zstream *zstream)
 {
-	int zerr;
-
-	if ((zerr = deflateInit(zstream, Z_DEFAULT_COMPRESSION)) != Z_OK)
-		return zstream_seterr(zerr, zstream);
-
-	return 0;
+	zstream->zerr = deflateInit(&zstream->z, Z_DEFAULT_COMPRESSION);
+	return zstream_seterr(zstream);
 }
 
-ssize_t git_zstream_deflate(void *out, size_t out_len, git_zstream *zstream, const void *in, size_t in_len)
+void git_zstream_free(git_zstream *zstream)
 {
-	int zerr;
-
-	if ((ssize_t)out_len < 0)
-		out_len = INT_MAX;
+	deflateEnd(&zstream->z);
+}
 
-	zstream->next_in = (Bytef *)in;
-	zstream->avail_in = in_len;
-	zstream->next_out = out;
-	zstream->avail_out = out_len;
+void git_zstream_reset(git_zstream *zstream)
+{
+	deflateReset(&zstream->z);
+	zstream->in = NULL;
+	zstream->in_len = 0;
+	zstream->zerr = Z_STREAM_END;
+}
 
-	if ((zerr = deflate(zstream, Z_FINISH)) == Z_STREAM_ERROR)
-		return zstream_seterr(zerr, zstream);
+int git_zstream_set_input(git_zstream *zstream, const void *in, size_t in_len)
+{
+	zstream->in = in;
+	zstream->in_len = in_len;
+	zstream->zerr = Z_OK;
+	return 0;
+}
 
-	return (out_len - zstream->avail_out);
+bool git_zstream_done(git_zstream *zstream)
+{
+	return (!zstream->in_len && zstream->zerr == Z_STREAM_END);
 }
 
-void git_zstream_reset(git_zstream *zstream)
+size_t git_zstream_suggest_output_len(git_zstream *zstream)
 {
-	deflateReset(zstream);
+	if (zstream->in_len > ZSTREAM_BUFFER_SIZE)
+		return ZSTREAM_BUFFER_SIZE;
+	else if (zstream->in_len > ZSTREAM_BUFFER_MIN_EXTRA)
+		return zstream->in_len;
+	else
+		return ZSTREAM_BUFFER_MIN_EXTRA;
 }
 
-void git_zstream_free(git_zstream *zstream)
+int git_zstream_get_output(void *out, size_t *out_len, git_zstream *zstream)
 {
-	deflateEnd(zstream);
+	int zflush = Z_FINISH;
+	size_t out_remain = *out_len;
+
+	while (out_remain > 0 && zstream->zerr != Z_STREAM_END) {
+		size_t out_queued, in_queued, out_used, in_used;
+
+		/* set up in data */
+		zstream->z.next_in  = (Bytef *)zstream->in;
+		zstream->z.avail_in = (uInt)zstream->in_len;
+		if ((size_t)zstream->z.avail_in != zstream->in_len) {
+			zstream->z.avail_in = INT_MAX;
+			zflush = Z_NO_FLUSH;
+		} else {
+			zflush = Z_FINISH;
+		}
+		in_queued = (size_t)zstream->z.avail_in;
+
+		/* set up out data */
+		zstream->z.next_out = out;
+		zstream->z.avail_out = (uInt)out_remain;
+		if ((size_t)zstream->z.avail_out != out_remain)
+			zstream->z.avail_out = INT_MAX;
+		out_queued = (size_t)zstream->z.avail_out;
+
+		/* compress next chunk */
+		zstream->zerr = deflate(&zstream->z, zflush);
+
+		if (zstream->zerr == Z_STREAM_ERROR)
+			return zstream_seterr(zstream);
+
+		out_used = (out_queued - zstream->z.avail_out);
+		out_remain -= out_used;
+		out = ((char *)out) + out_used;
+
+		in_used = (in_queued - zstream->z.avail_in);
+		zstream->in_len -= in_used;
+		zstream->in += in_used;
+	}
+
+	/* either we finished the input or we did not flush the data */
+	assert(zstream->in_len > 0 || zflush == Z_FINISH);
+
+	/* set out_size to number of bytes actually written to output */
+	*out_len = *out_len - out_remain;
+
+	return 0;
 }
 
 int git_zstream_deflatebuf(git_buf *out, const void *in, size_t in_len)
 {
-	git_zstream zstream = GIT_ZSTREAM_INIT;
-	size_t out_len;
-	ssize_t written;
+	git_zstream zs = GIT_ZSTREAM_INIT;
 	int error = 0;
 
-	if ((error = git_zstream_init(&zstream)) < 0)
+	if ((error = git_zstream_init(&zs)) < 0)
 		return error;
 
-	do {
-		if (out->asize - out->size < BUFFER_SIZE)
-			git_buf_grow(out, out->asize + BUFFER_SIZE);
+	if ((error = git_zstream_set_input(&zs, in, in_len)) < 0)
+		goto done;
+
+	while (!git_zstream_done(&zs)) {
+		size_t step = git_zstream_suggest_output_len(&zs), written;
+
+		if ((error = git_buf_grow(out, out->asize + step)) < 0)
+			goto done;
 
-		out_len = out->asize - out->size;
+		written = out->asize - out->size;
 
-		if ((written = git_zstream_deflate(out->ptr + out->size, out_len, &zstream, in, in_len)) <= 0)
-			break;
+		if ((error = git_zstream_get_output(
+				out->ptr + out->size, &written, &zs)) < 0)
+			goto done;
 
-		in = (char *)in + written;
-		in_len -= written;
 		out->size += written;
-	} while (written > 0);
+	}
 
-	if (written < 0)
-		error = written;
+	/* NULL terminate for consistency if possible */
+	if (out->size < out->asize)
+		out->ptr[out->size] = '\0';
 
-	git_zstream_free(&zstream);
+done:
+	git_zstream_free(&zs);
 	return error;
 }
diff --git a/src/zstream.h b/src/zstream.h
index 9672903..9b5bf6a 100644
--- a/src/zstream.h
+++ b/src/zstream.h
@@ -12,15 +12,28 @@
 #include "common.h"
 #include "buffer.h"
 
-#define git_zstream z_stream
+typedef struct {
+	z_stream z;
+	const char *in;
+	size_t in_len;
+	int zerr;
+} git_zstream;
 
-#define GIT_ZSTREAM_INIT {0}
+#define GIT_ZSTREAM_INIT {{0}}
 
 int git_zstream_init(git_zstream *zstream);
-ssize_t git_zstream_deflate(void *out, size_t out_len, git_zstream *zstream, const void *in, size_t in_len);
-void git_zstream_reset(git_zstream *zstream);
 void git_zstream_free(git_zstream *zstream);
 
+int git_zstream_set_input(git_zstream *zstream, const void *in, size_t in_len);
+
+size_t git_zstream_suggest_output_len(git_zstream *zstream);
+
+int git_zstream_get_output(void *out, size_t *out_len, git_zstream *zstream);
+
+bool git_zstream_done(git_zstream *zstream);
+
+void git_zstream_reset(git_zstream *zstream);
+
 int git_zstream_deflatebuf(git_buf *out, const void *in, size_t in_len);
 
 #endif /* INCLUDE_zstream_h__ */
diff --git a/tests/core/zstream.c b/tests/core/zstream.c
new file mode 100644
index 0000000..7ba9424
--- /dev/null
+++ b/tests/core/zstream.c
@@ -0,0 +1,143 @@
+#include "clar_libgit2.h"
+#include "buffer.h"
+#include "zstream.h"
+
+static const char *data = "This is a test test test of This is a test";
+
+#define INFLATE_EXTRA 2
+
+static void assert_zlib_equal_(
+	const void *expected, size_t e_len,
+	const void *compressed, size_t c_len,
+	const char *msg, const char *file, int line)
+{
+	z_stream stream;
+	char *expanded = git__calloc(1, e_len + INFLATE_EXTRA);
+	cl_assert(expanded);
+
+	memset(&stream, 0, sizeof(stream));
+	stream.next_out  = (Bytef *)expanded;
+	stream.avail_out = (uInt)(e_len + INFLATE_EXTRA);
+	stream.next_in   = (Bytef *)compressed;
+	stream.avail_in  = (uInt)c_len;
+
+	cl_assert(inflateInit(&stream) == Z_OK);
+	cl_assert(inflate(&stream, Z_FINISH));
+	inflateEnd(&stream);
+
+	clar__assert_equal(
+		file, line, msg, 1,
+		"%d", (int)stream.total_out, (int)e_len);
+	clar__assert_equal(
+		file, line, "Buffer len was not exact match", 1,
+		"%d", (int)stream.avail_out, (int)INFLATE_EXTRA);
+
+	clar__assert(
+		memcmp(expanded, expected, e_len) == 0,
+		file, line, "uncompressed data did not match", NULL, 1);
+
+	git__free(expanded);
+}
+
+#define assert_zlib_equal(E,EL,C,CL) \
+	assert_zlib_equal_(E, EL, C, CL, #EL " != " #CL, __FILE__, (int)__LINE__)
+
+void test_core_zstream__basic(void)
+{
+	git_zstream z = GIT_ZSTREAM_INIT;
+	char out[128];
+	size_t outlen = sizeof(out);
+
+	cl_git_pass(git_zstream_init(&z));
+	cl_git_pass(git_zstream_set_input(&z, data, strlen(data) + 1));
+	cl_git_pass(git_zstream_get_output(out, &outlen, &z));
+	cl_assert(git_zstream_done(&z));
+	cl_assert(outlen > 0);
+	git_zstream_free(&z);
+
+	assert_zlib_equal(data, strlen(data) + 1, out, outlen);
+}
+
+void test_core_zstream__buffer(void)
+{
+	git_buf out = GIT_BUF_INIT;
+	cl_git_pass(git_zstream_deflatebuf(&out, data, strlen(data) + 1));
+	assert_zlib_equal(data, strlen(data) + 1, out.ptr, out.size);
+	git_buf_free(&out);
+}
+
+#define BIG_STRING_PART "Big Data IS Big - Long Data IS Long - We need a buffer larger than 1024 x 1024 to make sure we trigger chunked compression - Big Big Data IS Bigger than Big - Long Long Data IS Longer than Long"
+
+static void compress_input_various_ways(git_buf *input)
+{
+	git_buf out1 = GIT_BUF_INIT, out2 = GIT_BUF_INIT;
+	size_t i, fixed_size = max(input->size / 2, 256);
+	char *fixed = git__malloc(fixed_size);
+	cl_assert(fixed);
+
+	/* compress with deflatebuf */
+
+	cl_git_pass(git_zstream_deflatebuf(&out1, input->ptr, input->size));
+	assert_zlib_equal(input->ptr, input->size, out1.ptr, out1.size);
+
+	/* compress with various fixed size buffer (accumulating the output) */
+
+	for (i = 0; i < 3; ++i) {
+		git_zstream zs = GIT_ZSTREAM_INIT;
+		size_t use_fixed_size;
+
+		switch (i) {
+		case 0: use_fixed_size = 256; break;
+		case 1: use_fixed_size = fixed_size / 2; break;
+		case 2: use_fixed_size = fixed_size; break;
+		}
+		cl_assert(use_fixed_size <= fixed_size);
+
+		cl_git_pass(git_zstream_init(&zs));
+		cl_git_pass(git_zstream_set_input(&zs, input->ptr, input->size));
+
+		while (!git_zstream_done(&zs)) {
+			size_t written = use_fixed_size;
+			cl_git_pass(git_zstream_get_output(fixed, &written, &zs));
+			cl_git_pass(git_buf_put(&out2, fixed, written));
+		}
+
+		git_zstream_free(&zs);
+		assert_zlib_equal(input->ptr, input->size, out2.ptr, out2.size);
+
+		/* did both approaches give the same data? */
+		cl_assert_equal_sz(out1.size, out2.size);
+		cl_assert(!memcmp(out1.ptr, out2.ptr, out1.size));
+
+		git_buf_free(&out2);
+	}
+
+	git_buf_free(&out1);
+	git__free(fixed);
+}
+
+void test_core_zstream__big_data(void)
+{
+	git_buf in = GIT_BUF_INIT;
+	size_t scan, target;
+
+	for (target = 1024; target <= 1024 * 1024 * 4; target *= 8) {
+
+		/* make a big string that's easy to compress */
+		git_buf_clear(&in);
+		while (in.size < target)
+			cl_git_pass(
+				git_buf_put(&in, BIG_STRING_PART, strlen(BIG_STRING_PART)));
+
+		compress_input_various_ways(&in);
+
+		/* make a big string that's hard to compress */
+		srand(0xabad1dea);
+		for (scan = 0; scan < in.size; ++scan)
+			in.ptr[scan] = (char)rand();
+
+		compress_input_various_ways(&in);
+	}
+
+	git_buf_free(&in);
+}
diff --git a/tests/status/renames.c b/tests/status/renames.c
index a81910e..df5e230 100644
--- a/tests/status/renames.c
+++ b/tests/status/renames.c
@@ -560,7 +560,6 @@ void test_status_renames__zero_byte_file_does_not_fail(void)
 {
 	git_status_list *statuslist;
 	git_status_options opts = GIT_STATUS_OPTIONS_INIT;
-	status_entry_counts counts = {0};
 
 	struct status_entry expected[] = {
 		{ GIT_STATUS_WT_DELETED, "ikeepsix.txt", "ikeepsix.txt" },
diff --git a/tests/submodule/modify.c b/tests/submodule/modify.c
index 8ec9fce..e3e4d8a 100644
--- a/tests/submodule/modify.c
+++ b/tests/submodule/modify.c
@@ -178,25 +178,28 @@ void test_submodule_modify__edit_and_save(void)
 	cl_git_pass(git_submodule_set_url(sm1, SM_LIBGIT2_URL));
 	old_ignore = git_submodule_set_ignore(sm1, GIT_SUBMODULE_IGNORE_UNTRACKED);
 	old_update = git_submodule_set_update(sm1, GIT_SUBMODULE_UPDATE_REBASE);
-	old_fetchrecurse = git_submodule_set_fetch_recurse_submodules(sm1, GIT_SUBMODULE_RECURSE_YES);
+	old_fetchrecurse = git_submodule_set_fetch_recurse_submodules(
+		sm1, GIT_SUBMODULE_RECURSE_YES);
 
 	cl_assert_equal_s(SM_LIBGIT2_URL, git_submodule_url(sm1));
 	cl_assert_equal_i(
-		(int)GIT_SUBMODULE_IGNORE_UNTRACKED, (int)git_submodule_ignore(sm1));
+		GIT_SUBMODULE_IGNORE_UNTRACKED, git_submodule_ignore(sm1));
 	cl_assert_equal_i(
-		(int)GIT_SUBMODULE_UPDATE_REBASE, (int)git_submodule_update(sm1));
-	cl_assert_equal_i(GIT_SUBMODULE_RECURSE_YES, git_submodule_fetch_recurse_submodules(sm1));
+		GIT_SUBMODULE_UPDATE_REBASE, git_submodule_update(sm1));
+	cl_assert_equal_i(
+		GIT_SUBMODULE_RECURSE_YES, git_submodule_fetch_recurse_submodules(sm1));
 
 	/* revert without saving (and confirm setters return old value) */
 	cl_git_pass(git_submodule_set_url(sm1, old_url));
 	cl_assert_equal_i(
-		(int)GIT_SUBMODULE_IGNORE_UNTRACKED,
-		(int)git_submodule_set_ignore(sm1, GIT_SUBMODULE_IGNORE_RESET));
+		GIT_SUBMODULE_IGNORE_UNTRACKED,
+		git_submodule_set_ignore(sm1, GIT_SUBMODULE_IGNORE_RESET));
 	cl_assert_equal_i(
-		(int)GIT_SUBMODULE_UPDATE_REBASE,
-		(int)git_submodule_set_update(sm1, GIT_SUBMODULE_UPDATE_RESET));
+		GIT_SUBMODULE_UPDATE_REBASE,
+		git_submodule_set_update(sm1, GIT_SUBMODULE_UPDATE_RESET));
 	cl_assert_equal_i(
-		GIT_SUBMODULE_RECURSE_YES, git_submodule_set_fetch_recurse_submodules(sm1, old_fetchrecurse));
+		GIT_SUBMODULE_RECURSE_YES, git_submodule_set_fetch_recurse_submodules(
+			sm1, GIT_SUBMODULE_RECURSE_RESET));
 
 	/* check that revert was successful */
 	cl_assert_equal_s(old_url, git_submodule_url(sm1));
@@ -243,19 +246,22 @@ void test_submodule_modify__edit_and_save(void)
 
 	cl_assert_equal_s(SM_LIBGIT2_URL, git_submodule_url(sm2));
 	cl_assert_equal_i(
-		(int)GIT_SUBMODULE_IGNORE_UNTRACKED, (int)git_submodule_ignore(sm2));
+		GIT_SUBMODULE_IGNORE_UNTRACKED, git_submodule_ignore(sm2));
 	cl_assert_equal_i(
-		(int)GIT_SUBMODULE_UPDATE_REBASE, (int)git_submodule_update(sm2));
-	cl_assert_equal_i(GIT_SUBMODULE_RECURSE_YES, git_submodule_fetch_recurse_submodules(sm2));
+		GIT_SUBMODULE_UPDATE_REBASE, git_submodule_update(sm2));
+	cl_assert_equal_i(
+		GIT_SUBMODULE_RECURSE_NO, git_submodule_fetch_recurse_submodules(sm2));
 
 	/* set fetchRecurseSubmodules on-demand */
 	cl_git_pass(git_submodule_reload(sm1));
 	git_submodule_set_fetch_recurse_submodules(sm1, GIT_SUBMODULE_RECURSE_ONDEMAND);
-	cl_assert_equal_i(GIT_SUBMODULE_RECURSE_ONDEMAND, git_submodule_fetch_recurse_submodules(sm1));
+	cl_assert_equal_i(
+		GIT_SUBMODULE_RECURSE_ONDEMAND, git_submodule_fetch_recurse_submodules(sm1));
 	/* call save */
 	cl_git_pass(git_submodule_save(sm1));
 	cl_git_pass(git_submodule_reload(sm1));
-	cl_assert_equal_i(GIT_SUBMODULE_RECURSE_ONDEMAND, git_submodule_fetch_recurse_submodules(sm1));
+	cl_assert_equal_i(
+		GIT_SUBMODULE_RECURSE_ONDEMAND, git_submodule_fetch_recurse_submodules(sm1));
 
 	git_repository_free(r2);
 	git__free(old_url);