diff: parse patches with sha256

24 files changed, 307 insertions, 139 deletions

diff --git a/examples/diff.c b/examples/diff.c
index a9fb5d442..80c5200e9 100644
--- a/examples/diff.c
+++ b/examples/diff.c
@@ -188,9 +188,17 @@ static void compute_diff_no_index(git_diff **diff, struct diff_options *o) {
 	check_lg2(
 		git_patch_to_buf(&buf, patch),
 		"patch to buf", NULL);
+
+#ifdef GIT_EXPERIMENTAL_SHA256
+	check_lg2(
+		git_diff_from_buffer(diff, buf.ptr, buf.size, NULL),
+		"diff from patch", NULL);
+#else
 	check_lg2(
 		git_diff_from_buffer(diff, buf.ptr, buf.size),
 		"diff from patch", NULL);
+#endif
+
 	git_patch_free(patch);
 	git_buf_dispose(&buf);
 	free(file1_str);
diff --git a/include/git2/diff.h b/include/git2/diff.h
index 850d215a6..384b6e745 100644
--- a/include/git2/diff.h
+++ b/include/git2/diff.h
@@ -422,6 +422,22 @@ typedef struct {
 	uint32_t    interhunk_lines;
 
 	/**
+	 * The object ID type to emit in diffs; this is used by functions
+	 * that operate without a repository - namely `git_diff_buffers`,
+	 * or `git_diff_blobs` and `git_diff_blob_to_buffer` when one blob
+	 * is `NULL`.
+	 *
+	 * This may be omitted (set to `0`). If a repository is available,
+	 * the object ID format of the repository will be used. If no
+	 * repository is available then the default is `GIT_OID_SHA`.
+	 *
+	 * If this is specified and a repository is available, then the
+	 * specified `oid_type` must match the repository's object ID
+	 * format.
+	 */
+	git_oid_t   oid_type;
+
+	/**
 	 * The abbreviation length to use when formatting object ids.
 	 * Defaults to the value of 'core.abbrev' from the config, or 7 if unset.
 	 */
@@ -1153,9 +1169,8 @@ GIT_EXTERN(int) git_diff_to_buf(
 
 /**@}*/
 
-
 /*
- * Misc
+ * Low-level file comparison, invoking callbacks per difference.
  */
 
 /**
@@ -1271,6 +1286,25 @@ GIT_EXTERN(int) git_diff_buffers(
 	git_diff_line_cb line_cb,
 	void *payload);
 
+/* Patch file parsing. */
+
+/**
+ * Options for parsing a diff / patch file.
+ */
+typedef struct {
+	unsigned int version;
+	git_oid_t oid_type;
+} git_diff_parse_options;
+
+/* The current version of the diff parse options structure */
+#define GIT_DIFF_PARSE_OPTIONS_VERSION 1
+
+/* Stack initializer for diff parse options.  Alternatively use
+ * `git_diff_parse_options_init` programmatic initialization.
+ */
+#define GIT_DIFF_PARSE_OPTIONS_INIT \
+	{ GIT_DIFF_PARSE_OPTIONS_VERSION, GIT_OID_DEFAULT }
+
 /**
  * Read the contents of a git patch file into a `git_diff` object.
  *
@@ -1293,7 +1327,11 @@ GIT_EXTERN(int) git_diff_buffers(
 GIT_EXTERN(int) git_diff_from_buffer(
 	git_diff **out,
 	const char *content,
-	size_t content_len);
+	size_t content_len
+#ifdef GIT_EXPERIMENTAL_SHA256
+	, git_diff_parse_options *opts
+#endif
+	);
 
 /**
  * This is an opaque structure which is allocated by `git_diff_get_stats`.
diff --git a/src/libgit2/diff.c b/src/libgit2/diff.c
index 20a18c4b9..db12ccd68 100644
--- a/src/libgit2/diff.c
+++ b/src/libgit2/diff.c
@@ -19,8 +19,10 @@
 #include "git2/email.h"
 
 struct patch_id_args {
+	git_diff *diff;
 	git_hash_ctx ctx;
 	git_oid result;
+	git_oid_t oid_type;
 	int first_file;
 };
 
@@ -280,17 +282,19 @@ int git_diff_find_options_init(
 	return 0;
 }
 
-static int flush_hunk(git_oid *result, git_hash_ctx *ctx)
+static int flush_hunk(git_oid *result, struct patch_id_args *args)
 {
+	git_hash_ctx *ctx = &args->ctx;
 	git_oid hash;
 	unsigned short carry = 0;
-	int error, i;
+	size_t i;
+	int error;
 
 	if ((error = git_hash_final(hash.id, ctx)) < 0 ||
 	    (error = git_hash_init(ctx)) < 0)
 		return error;
 
-	for (i = 0; i < GIT_OID_SHA1_SIZE; i++) {
+	for (i = 0; i < git_oid_size(args->oid_type); i++) {
 		carry += result->id[i] + hash.id[i];
 		result->id[i] = (unsigned char)carry;
 		carry >>= 8;
@@ -338,7 +342,7 @@ static int diff_patchid_print_callback_to_buf(
 
 	if (line->origin == GIT_DIFF_LINE_FILE_HDR &&
 	    !args->first_file &&
-	    (error = flush_hunk(&args->result, &args->ctx) < 0))
+	    (error = flush_hunk(&args->result, args) < 0))
 			goto out;
 
 	if ((error = git_hash_update(&args->ctx, buf.ptr, buf.size)) < 0)
@@ -362,14 +366,19 @@ int git_diff_patchid_options_init(git_diff_patchid_options *opts, unsigned int v
 int git_diff_patchid(git_oid *out, git_diff *diff, git_diff_patchid_options *opts)
 {
 	struct patch_id_args args;
+	git_hash_algorithm_t algorithm;
 	int error;
 
 	GIT_ERROR_CHECK_VERSION(
 		opts, GIT_DIFF_PATCHID_OPTIONS_VERSION, "git_diff_patchid_options");
 
+	algorithm = git_oid_algorithm(diff->opts.oid_type);
+
 	memset(&args, 0, sizeof(args));
+	args.diff = diff;
 	args.first_file = 1;
-	if ((error = git_hash_ctx_init(&args.ctx, GIT_HASH_ALGORITHM_SHA1)) < 0)
+	args.oid_type = diff->opts.oid_type;
+	if ((error = git_hash_ctx_init(&args.ctx, algorithm)) < 0)
 		goto out;
 
 	if ((error = git_diff_print(diff,
@@ -378,11 +387,11 @@ int git_diff_patchid(git_oid *out, git_diff *diff, git_diff_patchid_options *opt
 				    &args)) < 0)
 		goto out;
 
-	if ((error = (flush_hunk(&args.result, &args.ctx))) < 0)
+	if ((error = (flush_hunk(&args.result, &args))) < 0)
 		goto out;
 
 #ifdef GIT_EXPERIMENTAL_SHA256
-	args.result.type = GIT_OID_SHA1;
+	args.result.type = diff->opts.oid_type;
 #endif
 
 	git_oid_cpy(out, &args.result);
diff --git a/src/libgit2/diff.h b/src/libgit2/diff.h
index 2cc35e65b..f21b27645 100644
--- a/src/libgit2/diff.h
+++ b/src/libgit2/diff.h
@@ -30,15 +30,15 @@ typedef enum {
 } git_diff_origin_t;
 
 struct git_diff {
-	git_refcount     rc;
+	git_refcount      rc;
 	git_repository   *repo;
-	git_attr_session attrsession;
+	git_attr_session  attrsession;
 	git_diff_origin_t type;
-	git_diff_options opts;
-	git_vector       deltas;    /* vector of git_diff_delta */
+	git_diff_options  opts;
+	git_vector        deltas;    /* vector of git_diff_delta */
 	git_pool pool;
-	git_iterator_t old_src;
-	git_iterator_t new_src;
+	git_iterator_t    old_src;
+	git_iterator_t    new_src;
 	git_diff_perfdata perf;
 
 	int (*strcomp)(const char *, const char *);
diff --git a/src/libgit2/diff_file.c b/src/libgit2/diff_file.c
index c2d08675a..6b7f9590c 100644
--- a/src/libgit2/diff_file.c
+++ b/src/libgit2/diff_file.c
@@ -144,7 +144,7 @@ int git_diff_file_content__init_from_src(
 
 	if (!src->blob && !src->buf) {
 		fc->flags |= GIT_DIFF_FLAG__NO_DATA;
-		git_oid_clear(&fc->file->id, GIT_OID_SHA1);
+		git_oid_clear(&fc->file->id, opts->oid_type);
 	} else {
 		fc->flags |= GIT_DIFF_FLAG__LOADED;
 		fc->file->flags |= GIT_DIFF_FLAG_VALID_ID;
@@ -154,7 +154,7 @@ int git_diff_file_content__init_from_src(
 			git_blob_dup((git_blob **)&fc->blob, (git_blob *) src->blob);
 			fc->file->size = git_blob_rawsize(src->blob);
 			git_oid_cpy(&fc->file->id, git_blob_id(src->blob));
-			fc->file->id_abbrev = GIT_OID_SHA1_HEXSIZE;
+			fc->file->id_abbrev = (uint16_t)git_oid_hexsize(repo->oid_type);
 
 			fc->map.len  = (size_t)fc->file->size;
 			fc->map.data = (char *)git_blob_rawcontent(src->blob);
@@ -162,10 +162,10 @@ int git_diff_file_content__init_from_src(
 			fc->flags |= GIT_DIFF_FLAG__FREE_BLOB;
 		} else {
 			int error;
-			if ((error = git_odb__hash(&fc->file->id, src->buf, src->buflen, GIT_OBJECT_BLOB, GIT_OID_SHA1)) < 0)
+			if ((error = git_odb__hash(&fc->file->id, src->buf, src->buflen, GIT_OBJECT_BLOB, opts->oid_type)) < 0)
 				return error;
 			fc->file->size = src->buflen;
-			fc->file->id_abbrev = GIT_OID_SHA1_HEXSIZE;
+			fc->file->id_abbrev = (uint16_t)git_oid_hexsize(opts->oid_type);
 
 			fc->map.len  = src->buflen;
 			fc->map.data = (char *)src->buf;
@@ -178,7 +178,7 @@ int git_diff_file_content__init_from_src(
 static int diff_file_content_commit_to_str(
 	git_diff_file_content *fc, bool check_status)
 {
-	char oid[GIT_OID_SHA1_HEXSIZE+1];
+	char oid[GIT_OID_MAX_HEXSIZE+1];
 	git_str content = GIT_STR_INIT;
 	const char *status = "";
 
@@ -420,7 +420,7 @@ static int diff_file_content_load_workdir(
 	if (!error && (fc->file->flags & GIT_DIFF_FLAG_VALID_ID) == 0) {
 		error = git_odb__hash(
 			&fc->file->id, fc->map.data, fc->map.len,
-			GIT_OBJECT_BLOB, GIT_OID_SHA1);
+			GIT_OBJECT_BLOB, diff_opts->oid_type);
 		fc->file->flags |= GIT_DIFF_FLAG_VALID_ID;
 	}
 
diff --git a/src/libgit2/diff_generate.c b/src/libgit2/diff_generate.c
index a88ce8c32..78fe510e7 100644
--- a/src/libgit2/diff_generate.c
+++ b/src/libgit2/diff_generate.c
@@ -61,8 +61,8 @@ static git_diff_delta *diff_delta__alloc(
 	}
 	delta->status = status;
 
-	git_oid_clear(&delta->old_file.id, GIT_OID_SHA1);
-	git_oid_clear(&delta->new_file.id, GIT_OID_SHA1);
+	git_oid_clear(&delta->old_file.id, diff->base.opts.oid_type);
+	git_oid_clear(&delta->new_file.id, diff->base.opts.oid_type);
 
 	return delta;
 }
@@ -149,10 +149,13 @@ static int diff_delta__from_one(
 	const git_index_entry *entry = nitem;
 	bool has_old = false;
 	git_diff_delta *delta;
+	git_oid_t oid_type;
 	const char *matched_pathspec;
 
 	GIT_ASSERT_ARG((oitem != NULL) ^ (nitem != NULL));
 
+	oid_type = diff->base.opts.oid_type;
+
 	if (oitem) {
 		entry = oitem;
 		has_old = true;
@@ -186,20 +189,23 @@ static int diff_delta__from_one(
 	GIT_ASSERT(status != GIT_DELTA_MODIFIED);
 	delta->nfiles = 1;
 
+	git_oid_clear(&delta->old_file.id, diff->base.opts.oid_type);
+	git_oid_clear(&delta->new_file.id, diff->base.opts.oid_type);
+
 	if (has_old) {
 		delta->old_file.mode = entry->mode;
 		delta->old_file.size = entry->file_size;
 		delta->old_file.flags |= GIT_DIFF_FLAG_EXISTS;
 		git_oid_cpy(&delta->old_file.id, &entry->id);
-		git_oid_clear(&delta->new_file.id, GIT_OID_SHA1);
-		delta->old_file.id_abbrev = GIT_OID_SHA1_HEXSIZE;
+		git_oid_clear(&delta->new_file.id, oid_type);
+		delta->old_file.id_abbrev = (uint16_t)git_oid_hexsize(oid_type);
 	} else /* ADDED, IGNORED, UNTRACKED */ {
 		delta->new_file.mode = entry->mode;
 		delta->new_file.size = entry->file_size;
 		delta->new_file.flags |= GIT_DIFF_FLAG_EXISTS;
-		git_oid_clear(&delta->old_file.id, GIT_OID_SHA1);
+		git_oid_clear(&delta->old_file.id, oid_type);
 		git_oid_cpy(&delta->new_file.id, &entry->id);
-		delta->new_file.id_abbrev = GIT_OID_SHA1_HEXSIZE;
+		delta->new_file.id_abbrev = (uint16_t)git_oid_hexsize(oid_type);
 	}
 
 	delta->old_file.flags |= GIT_DIFF_FLAG_VALID_ID;
@@ -225,6 +231,9 @@ static int diff_delta__from_two(
 	const git_oid *old_id = &old_entry->id;
 	git_diff_delta *delta;
 	const char *canonical_path = old_entry->path;
+	git_oid_t oid_type;
+
+	oid_type = diff->base.opts.oid_type;
 
 	if (status == GIT_DELTA_UNMODIFIED &&
 		DIFF_FLAG_ISNT_SET(diff, GIT_DIFF_INCLUDE_UNMODIFIED))
@@ -254,14 +263,14 @@ static int diff_delta__from_two(
 		delta->old_file.size = old_entry->file_size;
 		delta->old_file.mode = old_mode;
 		git_oid_cpy(&delta->old_file.id, old_id);
-		delta->old_file.id_abbrev = GIT_OID_SHA1_HEXSIZE;
+		delta->old_file.id_abbrev = (uint16_t)git_oid_hexsize(oid_type);
 		delta->old_file.flags |= GIT_DIFF_FLAG_VALID_ID |
 			GIT_DIFF_FLAG_EXISTS;
 	}
 
 	if (!git_index_entry_is_conflict(new_entry)) {
 		git_oid_cpy(&delta->new_file.id, new_id);
-		delta->new_file.id_abbrev = GIT_OID_SHA1_HEXSIZE;
+		delta->new_file.id_abbrev = (uint16_t)git_oid_hexsize(oid_type);
 		delta->new_file.size = new_entry->file_size;
 		delta->new_file.mode = new_mode;
 		delta->old_file.flags |= GIT_DIFF_FLAG_EXISTS;
@@ -490,6 +499,14 @@ static int diff_generated_apply_options(
 			return -1;
 	}
 
+	if (!diff->base.opts.oid_type) {
+		diff->base.opts.oid_type = repo->oid_type;
+	} else if (diff->base.opts.oid_type != repo->oid_type) {
+		git_error_set(GIT_ERROR_INVALID,
+			"specified object ID type does not match repository object ID type");
+		return -1;
+	}
+
 	/* flag INCLUDE_TYPECHANGE_TREES implies INCLUDE_TYPECHANGE */
 	if (DIFF_FLAG_IS_SET(diff, GIT_DIFF_INCLUDE_TYPECHANGE_TREES))
 		diff->base.opts.flags |= GIT_DIFF_INCLUDE_TYPECHANGE;
@@ -603,7 +620,7 @@ int git_diff__oid_for_file(
 	entry.mode = mode;
 	entry.file_size = (uint32_t)size;
 	entry.path = (char *)path;
-	git_oid_clear(&entry.id, GIT_OID_SHA1);
+	git_oid_clear(&entry.id, diff->opts.oid_type);
 
 	return git_diff__oid_for_entry(out, diff, &entry, mode, NULL);
 }
@@ -624,7 +641,7 @@ int git_diff__oid_for_entry(
 	GIT_ASSERT(d->type == GIT_DIFF_TYPE_GENERATED);
 	diff = (git_diff_generated *)d;
 
-	git_oid_clear(out, GIT_OID_SHA1);
+	git_oid_clear(out, diff->base.opts.oid_type);
 
 	if (git_repository_workdir_path(&full_path, diff->base.repo, entry.path) < 0)
 		return -1;
@@ -660,7 +677,8 @@ int git_diff__oid_for_entry(
 			git_error_clear();
 		}
 	} else if (S_ISLNK(mode)) {
-		error = git_odb__hashlink(out, full_path.ptr, GIT_OID_SHA1);
+		error = git_odb__hashlink(out, full_path.ptr,
+			diff->base.opts.oid_type);
 		diff->base.perf.oid_calculations++;
 	} else if (!git__is_sizet(entry.file_size)) {
 		git_error_set(GIT_ERROR_NOMEMORY, "file size overflow (for 32-bits) on '%s'",
@@ -676,7 +694,8 @@ int git_diff__oid_for_entry(
 		else {
 			error = git_odb__hashfd_filtered(
 				out, fd, (size_t)entry.file_size,
-				GIT_OBJECT_BLOB, GIT_OID_SHA1, fl);
+				GIT_OBJECT_BLOB, diff->base.opts.oid_type,
+				fl);
 			p_close(fd);
 			diff->base.perf.oid_calculations++;
 		}
@@ -785,7 +804,7 @@ static int maybe_modified(
 	git_diff_generated *diff,
 	diff_in_progress *info)
 {
-	git_oid noid = GIT_OID_SHA1_ZERO;
+	git_oid noid;
 	git_delta_t status = GIT_DELTA_MODIFIED;
 	const git_index_entry *oitem = info->oitem;
 	const git_index_entry *nitem = info->nitem;
@@ -796,6 +815,8 @@ static int maybe_modified(
 	const char *matched_pathspec;
 	int error = 0;
 
+	git_oid_clear(&noid, diff->base.opts.oid_type);
+
 	if (!diff_pathspec_match(&matched_pathspec, diff, oitem))
 		return 0;
 
@@ -1700,11 +1721,11 @@ int git_diff__commit(
 	*out = NULL;
 
 	if ((parents = git_commit_parentcount(commit)) > 1) {
-		char commit_oidstr[GIT_OID_SHA1_HEXSIZE + 1];
+		char commit_oidstr[GIT_OID_MAX_HEXSIZE + 1];
 
 		error = -1;
 		git_error_set(GIT_ERROR_INVALID, "commit %s is a merge commit",
-			git_oid_tostr(commit_oidstr, GIT_OID_SHA1_HEXSIZE + 1, git_commit_id(commit)));
+			git_oid_tostr(commit_oidstr, GIT_OID_MAX_HEXSIZE + 1, git_commit_id(commit)));
 		goto on_error;
 	}
 
diff --git a/src/libgit2/diff_parse.c b/src/libgit2/diff_parse.c
index 75e41a544..04603969e 100644
--- a/src/libgit2/diff_parse.c
+++ b/src/libgit2/diff_parse.c
@@ -29,7 +29,7 @@ static void diff_parsed_free(git_diff *d)
 	git__free(diff);
 }
 
-static git_diff_parsed *diff_parsed_alloc(void)
+static git_diff_parsed *diff_parsed_alloc(git_oid_t oid_type)
 {
 	git_diff_parsed *diff;
 
@@ -51,6 +51,7 @@ static git_diff_parsed *diff_parsed_alloc(void)
 	}
 
 	diff->base.opts.flags &= ~GIT_DIFF_IGNORE_CASE;
+	diff->base.opts.oid_type = oid_type;
 
 	if (git_pool_init(&diff->base.pool, 1) < 0 ||
 	    git_vector_init(&diff->patches, 0, NULL) < 0 ||
@@ -67,19 +68,34 @@ static git_diff_parsed *diff_parsed_alloc(void)
 int git_diff_from_buffer(
 	git_diff **out,
 	const char *content,
-	size_t content_len)
+	size_t content_len
+#ifdef GIT_EXPERIMENTAL_SHA256
+	, git_diff_parse_options *opts
+#endif
+	)
 {
 	git_diff_parsed *diff;
 	git_patch *patch;
 	git_patch_parse_ctx *ctx = NULL;
+	git_patch_options patch_opts = GIT_PATCH_OPTIONS_INIT;
+	git_oid_t oid_type;
 	int error = 0;
 
 	*out = NULL;
 
-	diff = diff_parsed_alloc();
+#ifdef GIT_EXPERIMENTAL_SHA256
+	oid_type = (opts && opts->oid_type) ? opts->oid_type :
+		GIT_OID_DEFAULT;
+#else
+	oid_type = GIT_OID_DEFAULT;
+#endif
+
+	patch_opts.oid_type = oid_type;
+
+	diff = diff_parsed_alloc(oid_type);
 	GIT_ERROR_CHECK_ALLOC(diff);
 
-	ctx = git_patch_parse_ctx_init(content, content_len, NULL);
+	ctx = git_patch_parse_ctx_init(content, content_len, &patch_opts);
 	GIT_ERROR_CHECK_ALLOC(ctx);
 
 	while (ctx->parse_ctx.remain_len) {
diff --git a/src/libgit2/diff_print.c b/src/libgit2/diff_print.c
index 3077e11e1..32c936826 100644
--- a/src/libgit2/diff_print.c
+++ b/src/libgit2/diff_print.c
@@ -29,6 +29,7 @@ typedef struct {
 	const char *new_prefix;
 	uint32_t flags;
 	int id_strlen;
+	git_oid_t oid_type;
 
 	int (*strcomp)(const char *, const char *);
 } diff_print_info;
@@ -46,6 +47,8 @@ static int diff_print_info_init__common(
 	pi->payload = payload;
 	pi->buf = out;
 
+	GIT_ASSERT(pi->oid_type);
+
 	if (!pi->id_strlen) {
 		if (!repo)
 			pi->id_strlen = GIT_ABBREV_DEFAULT;
@@ -53,8 +56,9 @@ static int diff_print_info_init__common(
 			return -1;
 	}
 
-	if (pi->id_strlen > GIT_OID_SHA1_HEXSIZE)
-		pi->id_strlen = GIT_OID_SHA1_HEXSIZE;
+	if (pi->id_strlen > 0 &&
+	    (size_t)pi->id_strlen > git_oid_hexsize(pi->oid_type))
+		pi->id_strlen = (int)git_oid_hexsize(pi->oid_type);
 
 	memset(&pi->line, 0, sizeof(pi->line));
 	pi->line.old_lineno = -1;
@@ -78,6 +82,7 @@ static int diff_print_info_init_fromdiff(
 
 	if (diff) {
 		pi->flags = diff->opts.flags;
+		pi->oid_type = diff->opts.oid_type;
 		pi->id_strlen = diff->opts.id_abbrev;
 		pi->old_prefix = diff->opts.old_prefix;
 		pi->new_prefix = diff->opts.new_prefix;
@@ -101,6 +106,7 @@ static int diff_print_info_init_frompatch(
 	memset(pi, 0, sizeof(diff_print_info));
 
 	pi->flags = patch->diff_opts.flags;
+	pi->oid_type = patch->diff_opts.oid_type;
 	pi->id_strlen = patch->diff_opts.id_abbrev;
 	pi->old_prefix = patch->diff_opts.old_prefix;
 	pi->new_prefix = patch->diff_opts.new_prefix;
@@ -212,7 +218,10 @@ static int diff_print_one_raw(
 	git_str *out = pi->buf;
 	int id_abbrev;
 	char code = git_diff_status_char(delta->status);
-	char start_oid[GIT_OID_SHA1_HEXSIZE+1], end_oid[GIT_OID_SHA1_HEXSIZE+1];
+	char start_oid[GIT_OID_MAX_HEXSIZE + 1],
+	     end_oid[GIT_OID_MAX_HEXSIZE + 1];
+	size_t oid_hexsize;
+	bool id_is_abbrev;
 
 	GIT_UNUSED(progress);
 
@@ -231,12 +240,21 @@ static int diff_print_one_raw(
 		return -1;
 	}
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+	GIT_ASSERT(delta->old_file.id.type == delta->new_file.id.type);
+	oid_hexsize = git_oid_hexsize(delta->old_file.id.type);
+#else
+	oid_hexsize = GIT_OID_SHA1_HEXSIZE;
+#endif
+
+	id_is_abbrev = (pi->id_strlen > 0 &&
+	                (size_t)pi->id_strlen <= oid_hexsize);
+
 	git_oid_tostr(start_oid, pi->id_strlen + 1, &delta->old_file.id);
 	git_oid_tostr(end_oid, pi->id_strlen + 1, &delta->new_file.id);
 
-	git_str_printf(
-		out, (pi->id_strlen <= GIT_OID_SHA1_HEXSIZE) ?
-			":%06o %06o %s... %s... %c" : ":%06o %06o %s %s %c",
+	git_str_printf(out,
+		id_is_abbrev ? ":%06o %06o %s... %s... %c" : ":%06o %06o %s %s %c",
 		delta->old_file.mode, delta->new_file.mode, start_oid, end_oid, code);
 
 	if (delta->similarity > 0)
@@ -273,7 +291,8 @@ static int diff_print_oid_range(
 	git_str *out, const git_diff_delta *delta, int id_strlen,
 	bool print_index)
 {
-	char start_oid[GIT_OID_SHA1_HEXSIZE+1], end_oid[GIT_OID_SHA1_HEXSIZE+1];
+	char start_oid[GIT_OID_MAX_HEXSIZE + 1],
+	     end_oid[GIT_OID_MAX_HEXSIZE + 1];
 
 	if (delta->old_file.mode &&
 			id_strlen > delta->old_file.id_abbrev) {
diff --git a/src/libgit2/diff_tform.c b/src/libgit2/diff_tform.c
index 8c0c1b7fc..4a156c7a3 100644
--- a/src/libgit2/diff_tform.c
+++ b/src/libgit2/diff_tform.c
@@ -364,7 +364,7 @@ static int insert_delete_side_of_split(
 	memset(&deleted->new_file, 0, sizeof(deleted->new_file));
 	deleted->new_file.path = deleted->old_file.path;
 	deleted->new_file.flags |= GIT_DIFF_FLAG_VALID_ID;
-	git_oid_clear(&deleted->new_file.id, GIT_OID_SHA1);
+	git_oid_clear(&deleted->new_file.id, diff->opts.oid_type);
 
 	return git_vector_insert(onto, deleted);
 }
@@ -398,7 +398,7 @@ static int apply_splits_and_deletes(
 			memset(&delta->old_file, 0, sizeof(delta->old_file));
 			delta->old_file.path = delta->new_file.path;
 			delta->old_file.flags |= GIT_DIFF_FLAG_VALID_ID;
-			git_oid_clear(&delta->old_file.id, GIT_OID_SHA1);
+			git_oid_clear(&delta->old_file.id, diff->opts.oid_type);
 		}
 
 		/* clean up delta before inserting into new list */
@@ -997,7 +997,7 @@ find_best_matches:
 				memset(&src->new_file, 0, sizeof(src->new_file));
 				src->new_file.path = src->old_file.path;
 				src->new_file.flags |= GIT_DIFF_FLAG_VALID_ID;
-				git_oid_clear(&src->new_file.id, GIT_OID_SHA1);
+				git_oid_clear(&src->new_file.id, diff->opts.oid_type);
 
 				num_updates++;
 
@@ -1023,7 +1023,7 @@ find_best_matches:
 				memset(&src->old_file, 0, sizeof(src->old_file));
 				src->old_file.path = src->new_file.path;
 				src->old_file.flags |= GIT_DIFF_FLAG_VALID_ID;
-				git_oid_clear(&src->old_file.id, GIT_OID_SHA1);
+				git_oid_clear(&src->old_file.id, diff->opts.oid_type);
 
 				src->flags &= ~GIT_DIFF_FLAG__TO_SPLIT;
 				num_rewrites--;
diff --git a/src/libgit2/patch.h b/src/libgit2/patch.h
index 1e1471ed6..86328e886 100644
--- a/src/libgit2/patch.h
+++ b/src/libgit2/patch.h
@@ -59,9 +59,15 @@ typedef struct {
 	 * This prefix will be removed when looking for files.  The default is 1.
 	 */
 	uint32_t prefix_len;
+
+	/**
+	 * The type of object IDs in the patch file. The default is
+	 * `GIT_OID_DEFAULT`.
+	 */
+	git_oid_t oid_type;
 } git_patch_options;
 
-#define GIT_PATCH_OPTIONS_INIT { 1 }
+#define GIT_PATCH_OPTIONS_INIT { 1, GIT_OID_DEFAULT }
 
 extern int git_patch__to_buf(git_str *out, git_patch *patch);
 extern void git_patch_free(git_patch *patch);
diff --git a/src/libgit2/patch_generate.c b/src/libgit2/patch_generate.c
index bc598fea8..079bc53ae 100644
--- a/src/libgit2/patch_generate.c
+++ b/src/libgit2/patch_generate.c
@@ -81,7 +81,8 @@ static void patch_generated_init_common(git_patch_generated *patch)
 
 static int patch_generated_normalize_options(
 	git_diff_options *out,
-	const git_diff_options *opts)
+	const git_diff_options *opts,
+	git_repository *repo)
 {
 	if (opts) {
 		GIT_ERROR_CHECK_VERSION(opts, GIT_DIFF_OPTIONS_VERSION, "git_diff_options");
@@ -91,6 +92,23 @@ static int patch_generated_normalize_options(
 		memcpy(out, &default_opts, sizeof(git_diff_options));
 	}
 
+	if (repo && opts && opts->oid_type && repo->oid_type != opts->oid_type) {
+		/*
+		 * This limitation feels unnecessary - we should consider
+		 * allowing users to generate diffs with a different object
+		 * ID format than the repository.
+		 */
+		git_error_set(GIT_ERROR_INVALID,
+			"specified object ID type does not match repository object ID type");
+		return -1;
+	} else if (repo) {
+		out->oid_type = repo->oid_type;
+	} else if (opts && opts->oid_type) {
+		out->oid_type = opts->oid_type;
+	} else {
+		out->oid_type = GIT_OID_DEFAULT;
+	}
+
 	out->old_prefix = opts && opts->old_prefix ?
 		git__strdup(opts->old_prefix) :
 		git__strdup(DIFF_OLD_PREFIX_DEFAULT);
@@ -118,7 +136,7 @@ static int patch_generated_init(
 	patch->delta_index = delta_index;
 
 	if ((error = patch_generated_normalize_options(
-			&patch->base.diff_opts, &diff->opts)) < 0 ||
+			&patch->base.diff_opts, &diff->opts, diff->repo)) < 0 ||
 		(error = git_diff_file_content__init_from_diff(
 			&patch->ofile, diff, patch->base.delta, true)) < 0 ||
 		(error = git_diff_file_content__init_from_diff(
@@ -449,7 +467,7 @@ static int patch_generated_from_sources(
 	git_xdiff_output *xo,
 	git_diff_file_content_src *oldsrc,
 	git_diff_file_content_src *newsrc,
-	const git_diff_options *opts)
+	const git_diff_options *given_opts)
 {
 	int error = 0;
 	git_repository *repo =
@@ -457,11 +475,12 @@ static int patch_generated_from_sources(
 		newsrc->blob ? git_blob_owner(newsrc->blob) : NULL;
 	git_diff_file *lfile = &pd->delta.old_file, *rfile = &pd->delta.new_file;
 	git_diff_file_content *ldata = &pd->patch.ofile, *rdata = &pd->patch.nfile;
+	git_diff_options *opts = &pd->patch.base.diff_opts;
 
-	if ((error = patch_generated_normalize_options(&pd->patch.base.diff_opts, opts)) < 0)
+	if ((error = patch_generated_normalize_options(opts, given_opts, repo)) < 0)
 		return error;
 
-	if (opts && (opts->flags & GIT_DIFF_REVERSE) != 0) {
+	if ((opts->flags & GIT_DIFF_REVERSE) != 0) {
 		void *tmp = lfile; lfile = rfile; rfile = tmp;
 		tmp = ldata; ldata = rdata; rdata = tmp;
 	}
diff --git a/src/libgit2/patch_parse.c b/src/libgit2/patch_parse.c
index ffdb99231..c06915537 100644
--- a/src/libgit2/patch_parse.c
+++ b/src/libgit2/patch_parse.c
@@ -166,15 +166,19 @@ static int parse_header_oid(
 	uint16_t *oid_len,
 	git_patch_parse_ctx *ctx)
 {
-	size_t len;
+	size_t hexsize, len;
+
+	hexsize = git_oid_hexsize(ctx->opts.oid_type);
 
-	for (len = 0; len < ctx->parse_ctx.line_len && len < GIT_OID_SHA1_HEXSIZE; len++) {
+	for (len = 0;
+	     len < ctx->parse_ctx.line_len && len < hexsize;
+	     len++) {
 		if (!git__isxdigit(ctx->parse_ctx.line[len]))
 			break;
 	}
 
-	if (len < GIT_OID_MINPREFIXLEN || len > GIT_OID_SHA1_HEXSIZE ||
-		git_oid__fromstrn(oid, ctx->parse_ctx.line, len, GIT_OID_SHA1) < 0)
+	if (len < GIT_OID_MINPREFIXLEN || len > hexsize ||
+		git_oid__fromstrn(oid, ctx->parse_ctx.line, len, ctx->opts.oid_type) < 0)
 		return git_parse_err("invalid hex formatted object id at line %"PRIuZ,
 			ctx->parse_ctx.line_num);
 
@@ -1065,12 +1069,14 @@ static int check_patch(git_patch_parsed *patch)
 		return git_parse_err("patch with no hunks");
 
 	if (delta->status == GIT_DELTA_ADDED) {
-		git_oid_clear(&delta->old_file.id, GIT_OID_SHA1);
+		git_oid_clear(&delta->old_file.id,
+			patch->base.diff_opts.oid_type);
 		delta->old_file.id_abbrev = 0;
 	}
 
 	if (delta->status == GIT_DELTA_DELETED) {
-		git_oid_clear(&delta->new_file.id, GIT_OID_SHA1);
+		git_oid_clear(&delta->new_file.id,
+			patch->base.diff_opts.oid_type);
 		delta->new_file.id_abbrev = 0;
 	}
 
@@ -1187,11 +1193,13 @@ int git_patch_parse(
 	patch->base.delta->status = GIT_DELTA_MODIFIED;
 	patch->base.delta->nfiles = 2;
 
+	patch->base.diff_opts.oid_type = ctx->opts.oid_type;
+
 	start = ctx->parse_ctx.remain_len;
 
 	if ((error = parse_patch_header(patch, ctx)) < 0 ||
-		(error = parse_patch_body(patch, ctx)) < 0 ||
-		(error = check_patch(patch)) < 0)
+	    (error = parse_patch_body(patch, ctx)) < 0 ||
+	    (error = check_patch(patch)) < 0)
 		goto done;
 
 	used = start - ctx->parse_ctx.remain_len;
diff --git a/tests/libgit2/apply/apply_helpers.h b/tests/libgit2/apply/apply_helpers.h
index 82094773e..b1a1479de 100644
--- a/tests/libgit2/apply/apply_helpers.h
+++ b/tests/libgit2/apply/apply_helpers.h
@@ -1,4 +1,5 @@
 #include "../merge/merge_helpers.h"
+#include "../diff/diff_helpers.h"
 
 #define TEST_REPO_PATH "merge-recursive"
 
diff --git a/tests/libgit2/apply/both.c b/tests/libgit2/apply/both.c
index 1331e7ea4..44c5b1937 100644
--- a/tests/libgit2/apply/both.c
+++ b/tests/libgit2/apply/both.c
@@ -78,7 +78,7 @@ void test_apply_both__parsed_diff(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff,
+	cl_git_pass(diff_from_buffer(&diff,
 		DIFF_MODIFY_TWO_FILES, strlen(DIFF_MODIFY_TWO_FILES)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -102,7 +102,7 @@ void test_apply_both__removes_file(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 	    sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_DELETE_FILE,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_DELETE_FILE,
 		strlen(DIFF_DELETE_FILE)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -128,7 +128,7 @@ void test_apply_both__adds_file(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 	    sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff,
+	cl_git_pass(diff_from_buffer(&diff,
 		DIFF_ADD_FILE, strlen(DIFF_ADD_FILE)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -161,7 +161,7 @@ void test_apply_both__application_failure_leaves_index_unmodified(void)
 	cl_git_pass(git_index_write(index));
 	git_index_free(index);
 
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_fail_with(GIT_EAPPLYFAIL, git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
 	validate_apply_index(repo, index_expected, index_expected_cnt);
@@ -198,7 +198,7 @@ void test_apply_both__index_must_match_workdir(void)
 	cl_git_pass(git_index_write(index));
 	git_index_free(index);
 
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_fail_with(GIT_EAPPLYFAIL, git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
 	git_diff_free(diff);
@@ -214,7 +214,7 @@ void test_apply_both__index_mode_must_match_workdir(void)
 	/* Set a file in the working directory executable. */
 	cl_must_pass(p_chmod("merge-recursive/asparagus.txt", 0755));
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_MODIFY_TWO_FILES,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_MODIFY_TWO_FILES,
 	    strlen(DIFF_MODIFY_TWO_FILES)));
 	cl_git_fail_with(GIT_EAPPLYFAIL, git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -248,7 +248,7 @@ void test_apply_both__application_failure_leaves_workdir_unmodified(void)
 	cl_git_pass(git_index_write(index));
 	git_index_free(index);
 
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_fail_with(GIT_EAPPLYFAIL, git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
 	validate_apply_workdir(repo, workdir_expected, workdir_expected_cnt);
@@ -301,7 +301,7 @@ void test_apply_both__keeps_nonconflicting_changes(void)
 	cl_git_rmfile("merge-recursive/oyster.txt");
 	cl_git_rewritefile("merge-recursive/gravy.txt", "Hello, world.\n");
 
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
 	validate_apply_index(repo, index_expected, index_expected_cnt);
@@ -341,7 +341,7 @@ void test_apply_both__can_apply_nonconflicting_file_changes(void)
 	cl_git_pass(git_index_write(index));
 	git_index_free(index);
 
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
 	validate_apply_index(repo, both_expected, both_expected_cnt);
@@ -391,7 +391,7 @@ void test_apply_both__honors_crlf_attributes(void)
 	cl_git_pass(git_reset(repo, (git_object *)commit, GIT_RESET_HARD, NULL));
 	git_commit_free(commit);
 
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
 	validate_apply_index(repo, index_expected, index_expected_cnt);
@@ -415,7 +415,7 @@ void test_apply_both__rename(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_RENAME_FILE,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_RENAME_FILE,
 		strlen(DIFF_RENAME_FILE)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -440,7 +440,7 @@ void test_apply_both__rename_and_modify(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_RENAME_AND_MODIFY_FILE,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_RENAME_AND_MODIFY_FILE,
 		strlen(DIFF_RENAME_AND_MODIFY_FILE)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -465,7 +465,7 @@ void test_apply_both__rename_a_to_b_to_c(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_RENAME_A_TO_B_TO_C,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_RENAME_A_TO_B_TO_C,
 		strlen(DIFF_RENAME_A_TO_B_TO_C)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -490,7 +490,7 @@ void test_apply_both__rename_a_to_b_to_c_exact(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_RENAME_A_TO_B_TO_C_EXACT,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_RENAME_A_TO_B_TO_C_EXACT,
 		strlen(DIFF_RENAME_A_TO_B_TO_C_EXACT)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -515,7 +515,7 @@ void test_apply_both__rename_circular(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_RENAME_CIRCULAR,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_RENAME_CIRCULAR,
 		strlen(DIFF_RENAME_CIRCULAR)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -539,7 +539,7 @@ void test_apply_both__rename_2_to_1(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_RENAME_2_TO_1,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_RENAME_2_TO_1,
 		strlen(DIFF_RENAME_2_TO_1)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -565,7 +565,7 @@ void test_apply_both__rename_1_to_2(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_RENAME_1_TO_2,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_RENAME_1_TO_2,
 		strlen(DIFF_RENAME_1_TO_2)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -590,7 +590,7 @@ void test_apply_both__two_deltas_one_file(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_TWO_DELTAS_ONE_FILE,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_TWO_DELTAS_ONE_FILE,
 		strlen(DIFF_TWO_DELTAS_ONE_FILE)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -616,7 +616,7 @@ void test_apply_both__two_deltas_one_new_file(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_TWO_DELTAS_ONE_NEW_FILE,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_TWO_DELTAS_ONE_NEW_FILE,
 		strlen(DIFF_TWO_DELTAS_ONE_NEW_FILE)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -641,7 +641,7 @@ void test_apply_both__rename_and_modify_deltas(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_RENAME_AND_MODIFY_DELTAS,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_RENAME_AND_MODIFY_DELTAS,
 		strlen(DIFF_RENAME_AND_MODIFY_DELTAS)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -667,7 +667,7 @@ void test_apply_both__rename_delta_after_modify_delta(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_RENAME_AFTER_MODIFY,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_RENAME_AFTER_MODIFY,
 		strlen(DIFF_RENAME_AFTER_MODIFY)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -681,7 +681,7 @@ void test_apply_both__cant_rename_after_modify_nonexistent_target_path(void)
 {
 	git_diff *diff;
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_RENAME_AFTER_MODIFY_TARGET_PATH,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_RENAME_AFTER_MODIFY_TARGET_PATH,
 		strlen(DIFF_RENAME_AFTER_MODIFY_TARGET_PATH)));
 	cl_git_fail(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -692,7 +692,7 @@ void test_apply_both__cant_modify_source_path_after_rename(void)
 {
 	git_diff *diff;
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_RENAME_AND_MODIFY_SOURCE_PATH,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_RENAME_AND_MODIFY_SOURCE_PATH,
 		strlen(DIFF_RENAME_AND_MODIFY_SOURCE_PATH)));
 	cl_git_fail(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -714,7 +714,7 @@ void test_apply_both__readd_deleted_file(void)
 	size_t both_expected_cnt = sizeof(both_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_DELETE_AND_READD_FILE,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_DELETE_AND_READD_FILE,
 		strlen(DIFF_DELETE_AND_READD_FILE)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -728,7 +728,7 @@ void test_apply_both__cant_remove_file_twice(void)
 {
 	git_diff *diff;
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_REMOVE_FILE_TWICE,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_REMOVE_FILE_TWICE,
 		strlen(DIFF_REMOVE_FILE_TWICE)));
 	cl_git_fail(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
@@ -739,7 +739,7 @@ void test_apply_both__cant_add_invalid_filename(void)
 {
 	git_diff *diff;
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_ADD_INVALID_FILENAME,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_ADD_INVALID_FILENAME,
 		strlen(DIFF_ADD_INVALID_FILENAME)));
 	cl_git_fail(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
 
diff --git a/tests/libgit2/apply/callbacks.c b/tests/libgit2/apply/callbacks.c
index 2f9af3101..f076ca486 100644
--- a/tests/libgit2/apply/callbacks.c
+++ b/tests/libgit2/apply/callbacks.c
@@ -40,7 +40,7 @@ void test_apply_callbacks__delta_aborts(void)
 
 	opts.delta_cb = delta_abort_cb;
 
-	cl_git_pass(git_diff_from_buffer(&diff,
+	cl_git_pass(diff_from_buffer(&diff,
 		DIFF_MODIFY_TWO_FILES, strlen(DIFF_MODIFY_TWO_FILES)));
 	cl_git_fail_with(-99,
 		git_apply(repo, diff, GIT_APPLY_LOCATION_INDEX, &opts));
@@ -79,7 +79,7 @@ void test_apply_callbacks__delta_can_skip(void)
 
 	opts.delta_cb = delta_skip_cb;
 
-	cl_git_pass(git_diff_from_buffer(&diff,
+	cl_git_pass(diff_from_buffer(&diff,
 		DIFF_MODIFY_TWO_FILES, strlen(DIFF_MODIFY_TWO_FILES)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_WORKDIR, &opts));
 
@@ -117,7 +117,7 @@ void test_apply_callbacks__hunk_can_skip(void)
 	opts.hunk_cb = hunk_skip_odds_cb;
 	opts.payload = &count;
 
-	cl_git_pass(git_diff_from_buffer(&diff,
+	cl_git_pass(diff_from_buffer(&diff,
 		DIFF_MANY_CHANGES_ONE, strlen(DIFF_MANY_CHANGES_ONE)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_WORKDIR, &opts));
 
diff --git a/tests/libgit2/apply/check.c b/tests/libgit2/apply/check.c
index d055d455b..0c1f86dc5 100644
--- a/tests/libgit2/apply/check.c
+++ b/tests/libgit2/apply/check.c
@@ -60,7 +60,7 @@ void test_apply_check__parsed_diff(void)
 	git_apply_options opts = GIT_APPLY_OPTIONS_INIT;
 
 	opts.flags |= GIT_APPLY_CHECK;
-	cl_git_pass(git_diff_from_buffer(&diff,
+	cl_git_pass(diff_from_buffer(&diff,
 		DIFF_MODIFY_TWO_FILES, strlen(DIFF_MODIFY_TWO_FILES)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_INDEX, &opts));
 
@@ -76,7 +76,7 @@ void test_apply_check__binary(void)
    git_apply_options opts = GIT_APPLY_OPTIONS_INIT;
 
    opts.flags |= GIT_APPLY_CHECK;
-   cl_git_pass(git_diff_from_buffer(&diff,
+   cl_git_pass(diff_from_buffer(&diff,
        DIFF_MODIFY_TWO_FILES_BINARY,
        strlen(DIFF_MODIFY_TWO_FILES_BINARY)));
    cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_INDEX, &opts));
@@ -112,7 +112,7 @@ void test_apply_check__does_not_apply(void)
 	git_index_free(index);
 
 	opts.flags |= GIT_APPLY_CHECK;
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_fail_with(GIT_EAPPLYFAIL, git_apply(repo, diff, GIT_APPLY_LOCATION_INDEX, &opts));
 
 	validate_apply_index(repo, index_expected, index_expected_cnt);
diff --git a/tests/libgit2/apply/index.c b/tests/libgit2/apply/index.c
index 2dc0d53cb..564d55c8c 100644
--- a/tests/libgit2/apply/index.c
+++ b/tests/libgit2/apply/index.c
@@ -78,7 +78,7 @@ void test_apply_index__parsed_diff(void)
 	size_t index_expected_cnt = sizeof(index_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff,
+	cl_git_pass(diff_from_buffer(&diff,
 		DIFF_MODIFY_TWO_FILES, strlen(DIFF_MODIFY_TWO_FILES)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_INDEX, NULL));
 
@@ -102,7 +102,7 @@ void test_apply_index__removes_file(void)
 	size_t index_expected_cnt = sizeof(index_expected) /
 	    sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_DELETE_FILE,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_DELETE_FILE,
 		strlen(DIFF_DELETE_FILE)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_INDEX, NULL));
 
@@ -128,7 +128,7 @@ void test_apply_index__adds_file(void)
 	size_t index_expected_cnt = sizeof(index_expected) /
 	    sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff,
+	cl_git_pass(diff_from_buffer(&diff,
 		DIFF_ADD_FILE, strlen(DIFF_ADD_FILE)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_INDEX, NULL));
 
@@ -169,7 +169,7 @@ void test_apply_index__modified_workdir_with_unmodified_index_is_ok(void)
 	cl_git_rmfile("merge-recursive/asparagus.txt");
 	cl_git_rewritefile("merge-recursive/veal.txt", "Hello, world.\n");
 
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_INDEX, NULL));
 
 	validate_apply_index(repo, index_expected, index_expected_cnt);
@@ -201,7 +201,7 @@ void test_apply_index__application_failure_leaves_index_unmodified(void)
 	cl_git_pass(git_index_write(index));
 	git_index_free(index);
 
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_fail_with(GIT_EAPPLYFAIL, git_apply(repo, diff, GIT_APPLY_LOCATION_INDEX, NULL));
 
 	validate_apply_index(repo, index_expected, index_expected_cnt);
@@ -240,7 +240,7 @@ void test_apply_index__keeps_nonconflicting_changes(void)
 	cl_git_pass(git_index_write(index));
 	git_index_free(index);
 
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_INDEX, NULL));
 
 	validate_apply_index(repo, index_expected, index_expected_cnt);
@@ -285,7 +285,7 @@ void test_apply_index__can_apply_nonconflicting_file_changes(void)
 	cl_git_pass(git_index_write(index));
 	git_index_free(index);
 
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_INDEX, NULL));
 
 	validate_apply_index(repo, index_expected, index_expected_cnt);
@@ -311,7 +311,7 @@ void test_apply_index__change_mode(void)
 	size_t index_expected_cnt = sizeof(index_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_INDEX, NULL));
 
 	validate_apply_index(repo, index_expected, index_expected_cnt);
diff --git a/tests/libgit2/apply/tree.c b/tests/libgit2/apply/tree.c
index 667bb9d40..b97fe8d35 100644
--- a/tests/libgit2/apply/tree.c
+++ b/tests/libgit2/apply/tree.c
@@ -81,7 +81,7 @@ void test_apply_tree__adds_file(void)
 
 	cl_git_pass(git_commit_tree(&a_tree, a_commit));
 
-	cl_git_pass(git_diff_from_buffer(&diff,
+	cl_git_pass(diff_from_buffer(&diff,
 		DIFF_ADD_FILE, strlen(DIFF_ADD_FILE)));
 
 	cl_git_pass(git_apply_to_tree(&index, repo, a_tree, diff, NULL));
diff --git a/tests/libgit2/apply/workdir.c b/tests/libgit2/apply/workdir.c
index e1011d114..5ae56847a 100644
--- a/tests/libgit2/apply/workdir.c
+++ b/tests/libgit2/apply/workdir.c
@@ -77,7 +77,7 @@ void test_apply_workdir__parsed_diff(void)
 	size_t workdir_expected_cnt = sizeof(workdir_expected) /
 	    sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff,
+	cl_git_pass(diff_from_buffer(&diff,
 		DIFF_MODIFY_TWO_FILES, strlen(DIFF_MODIFY_TWO_FILES)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_WORKDIR, NULL));
 
@@ -101,7 +101,7 @@ void test_apply_workdir__removes_file(void)
 	size_t workdir_expected_cnt = sizeof(workdir_expected) /
 	    sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, DIFF_DELETE_FILE,
+	cl_git_pass(diff_from_buffer(&diff, DIFF_DELETE_FILE,
 		strlen(DIFF_DELETE_FILE)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_WORKDIR, NULL));
 
@@ -127,7 +127,7 @@ void test_apply_workdir__adds_file(void)
 	size_t workdir_expected_cnt = sizeof(workdir_expected) /
 	    sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff,
+	cl_git_pass(diff_from_buffer(&diff,
 		DIFF_ADD_FILE, strlen(DIFF_ADD_FILE)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_WORKDIR, NULL));
 
@@ -177,7 +177,7 @@ void test_apply_workdir__modified_index_with_unmodified_workdir_is_ok(void)
 	cl_git_pass(git_index_remove(index, "asparagus.txt", 0));
 	cl_git_pass(git_index_write(index));
 
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_WORKDIR, NULL));
 
 	validate_apply_index(repo, index_expected, index_expected_cnt);
@@ -208,7 +208,7 @@ void test_apply_workdir__application_failure_leaves_workdir_unmodified(void)
 	cl_git_rewritefile("merge-recursive/veal.txt",
 	    "This is a modification.\n");
 
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_fail_with(GIT_EAPPLYFAIL, git_apply(repo, diff, GIT_APPLY_LOCATION_WORKDIR, NULL));
 
 	validate_apply_workdir(repo, workdir_expected, workdir_expected_cnt);
@@ -233,7 +233,7 @@ void test_apply_workdir__keeps_nonconflicting_changes(void)
 	cl_git_rmfile("merge-recursive/oyster.txt");
 	cl_git_rewritefile("merge-recursive/gravy.txt", "Hello, world.\n");
 
-	cl_git_pass(git_diff_from_buffer(&diff,
+	cl_git_pass(diff_from_buffer(&diff,
 		DIFF_MODIFY_TWO_FILES, strlen(DIFF_MODIFY_TWO_FILES)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_WORKDIR, NULL));
 
@@ -268,7 +268,7 @@ void test_apply_workdir__can_apply_nonconflicting_file_changes(void)
 	cl_git_append2file("merge-recursive/asparagus.txt",
 	    "This line is added in the workdir.\n");
 
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_WORKDIR, NULL));
 
 	validate_index_unchanged(repo);
@@ -295,7 +295,7 @@ void test_apply_workdir__change_mode(void)
 	size_t workdir_expected_cnt = sizeof(workdir_expected) /
 		sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff, diff_file, strlen(diff_file)));
+	cl_git_pass(diff_from_buffer(&diff, diff_file, strlen(diff_file)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_WORKDIR, NULL));
 
 	validate_index_unchanged(repo);
@@ -321,7 +321,7 @@ void test_apply_workdir__apply_many_changes_one(void)
 	size_t workdir_expected_cnt = sizeof(workdir_expected) /
 	    sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff,
+	cl_git_pass(diff_from_buffer(&diff,
 		DIFF_MANY_CHANGES_ONE, strlen(DIFF_MANY_CHANGES_ONE)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_WORKDIR, &opts));
 
@@ -347,7 +347,7 @@ void test_apply_workdir__apply_many_changes_two(void)
 	size_t workdir_expected_cnt = sizeof(workdir_expected) /
 	    sizeof(struct merge_index_entry);
 
-	cl_git_pass(git_diff_from_buffer(&diff,
+	cl_git_pass(diff_from_buffer(&diff,
 		DIFF_MANY_CHANGES_TWO, strlen(DIFF_MANY_CHANGES_TWO)));
 	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_WORKDIR, &opts));
 
diff --git a/tests/libgit2/diff/diff_helpers.c b/tests/libgit2/diff/diff_helpers.c
index 341b0a448..5daebffeb 100644
--- a/tests/libgit2/diff/diff_helpers.c
+++ b/tests/libgit2/diff/diff_helpers.c
@@ -314,3 +314,20 @@ void diff_assert_equal(git_diff *a, git_diff *b)
 	}
 }
 
+#ifdef GIT_EXPERIMENTAL_SHA256
+int diff_from_buffer(
+	git_diff **out,
+	const char *content,
+	size_t content_len)
+{
+	return git_diff_from_buffer(out, content, content_len, NULL);
+}
+#else
+int diff_from_buffer(
+	git_diff **out,
+	const char *content,
+	size_t content_len)
+{
+	return git_diff_from_buffer(out, content, content_len);
+}
+#endif
diff --git a/tests/libgit2/diff/diff_helpers.h b/tests/libgit2/diff/diff_helpers.h
index af855ce68..1be4b4780 100644
--- a/tests/libgit2/diff/diff_helpers.h
+++ b/tests/libgit2/diff/diff_helpers.h
@@ -71,3 +71,7 @@ extern void diff_print_raw(FILE *fp, git_diff *diff);
 
 extern void diff_assert_equal(git_diff *a, git_diff *b);
 
+extern int diff_from_buffer(
+	git_diff **out,
+	const char *content,
+	size_t content_len);
diff --git a/tests/libgit2/diff/parse.c b/tests/libgit2/diff/parse.c
index cae843cc8..79745b995 100644
--- a/tests/libgit2/diff/parse.c
+++ b/tests/libgit2/diff/parse.c
@@ -19,19 +19,19 @@ void test_diff_parse__nonpatches_fail_with_notfound(void)
 	const char *not_with_both = "Lead.\n" PATCH_NOT_A_PATCH "Trail.\n";
 
 	cl_git_fail_with(GIT_ENOTFOUND,
-		git_diff_from_buffer(&diff,
+		diff_from_buffer(&diff,
 		not,
 		strlen(not)));
 	cl_git_fail_with(GIT_ENOTFOUND,
-		git_diff_from_buffer(&diff,
+		diff_from_buffer(&diff,
 		not_with_leading,
 		strlen(not_with_leading)));
 	cl_git_fail_with(GIT_ENOTFOUND,
-		git_diff_from_buffer(&diff,
+		diff_from_buffer(&diff,
 		not_with_trailing,
 		strlen(not_with_trailing)));
 	cl_git_fail_with(GIT_ENOTFOUND,
-		git_diff_from_buffer(&diff,
+		diff_from_buffer(&diff,
 		not_with_both,
 		strlen(not_with_both)));
 }
@@ -51,7 +51,7 @@ static void test_parse_invalid_diff(const char *invalid_diff)
 	git_str_puts(&buf, PATCH_BINARY_LITERAL);
 
 	cl_git_fail_with(GIT_ERROR,
-		git_diff_from_buffer(&diff, buf.ptr, buf.size));
+		diff_from_buffer(&diff, buf.ptr, buf.size));
 
 	git_str_dispose(&buf);
 }
@@ -72,7 +72,7 @@ void test_diff_parse__exact_rename(void)
 	    "2.9.3\n";
 	git_diff *diff;
 
-	cl_git_pass(git_diff_from_buffer(
+	cl_git_pass(diff_from_buffer(
 		&diff, content, strlen(content)));
 	git_diff_free(diff);
 }
@@ -92,7 +92,7 @@ void test_diff_parse__empty_file(void)
 	    "2.20.1\n";
 	git_diff *diff;
 
-	cl_git_pass(git_diff_from_buffer(
+	cl_git_pass(diff_from_buffer(
 		&diff, content, strlen(content)));
 	git_diff_free(diff);
 }
@@ -102,7 +102,7 @@ void test_diff_parse__no_extended_headers(void)
 	const char *content = PATCH_NO_EXTENDED_HEADERS;
 	git_diff *diff;
 
-	cl_git_pass(git_diff_from_buffer(
+	cl_git_pass(diff_from_buffer(
 		&diff, content, strlen(content)));
 	git_diff_free(diff);
 }
@@ -125,7 +125,7 @@ void test_diff_parse__add_delete_no_index(void)
 	    "-three\n";
 	git_diff *diff;
 
-	cl_git_pass(git_diff_from_buffer(
+	cl_git_pass(diff_from_buffer(
 		&diff, content, strlen(content)));
 	git_diff_free(diff);
 }
@@ -166,7 +166,7 @@ static void test_tree_to_tree_computed_to_parsed(
 	cl_git_pass(git_diff_to_buf(&computed_buf,
 		computed, GIT_DIFF_FORMAT_PATCH));
 
-	cl_git_pass(git_diff_from_buffer(&parsed,
+	cl_git_pass(diff_from_buffer(&parsed,
 		computed_buf.ptr, computed_buf.size));
 
 	diff_assert_equal(computed, parsed);
@@ -248,7 +248,7 @@ void test_diff_parse__get_patch_from_diff(void)
 		computed, GIT_DIFF_FORMAT_PATCH));
 	cl_git_pass(git_patch_from_diff(&patch_computed, computed, 0));
 
-	cl_git_pass(git_diff_from_buffer(&parsed,
+	cl_git_pass(diff_from_buffer(&parsed,
 		computed_buf.ptr, computed_buf.size));
 	cl_git_pass(git_patch_from_diff(&patch_parsed, parsed, 0));
 
@@ -292,7 +292,7 @@ void test_diff_parse__foreach_works_with_parsed_patch(void)
 	int called = 0;
 	git_diff *diff;
 
-	cl_git_pass(git_diff_from_buffer(&diff, patch, strlen(patch)));
+	cl_git_pass(diff_from_buffer(&diff, patch, strlen(patch)));
 	cl_git_pass(git_diff_foreach(diff, file_cb, NULL, NULL, NULL, &called));
 	cl_assert_equal_i(called, 1);
 
@@ -312,7 +312,7 @@ void test_diff_parse__parsing_minimal_patch_succeeds(void)
 	git_buf buf = GIT_BUF_INIT;
 	git_diff *diff;
 
-	cl_git_pass(git_diff_from_buffer(&diff, patch, strlen(patch)));
+	cl_git_pass(diff_from_buffer(&diff, patch, strlen(patch)));
 	cl_git_pass(git_diff_to_buf(&buf, diff, GIT_DIFF_FORMAT_PATCH));
 	cl_assert_equal_s(patch, buf.ptr);
 
@@ -330,7 +330,7 @@ void test_diff_parse__patch_roundtrip_succeeds(void)
 	cl_git_pass(git_patch_from_buffers(&patch, buf1, strlen(buf1), "obj1", buf2, strlen(buf2), "obj2", NULL));
 	cl_git_pass(git_patch_to_buf(&patchbuf, patch));
 
-	cl_git_pass(git_diff_from_buffer(&diff, patchbuf.ptr, patchbuf.size));
+	cl_git_pass(diff_from_buffer(&diff, patchbuf.ptr, patchbuf.size));
 	cl_git_pass(git_diff_to_buf(&diffbuf, diff, GIT_DIFF_FORMAT_PATCH));
 
 	cl_assert_equal_s(patchbuf.ptr, diffbuf.ptr);
@@ -372,7 +372,7 @@ void test_diff_parse__issue4672(void)
 	const git_diff_hunk *hunk;
 	size_t n, l = 0;
 
-	cl_git_pass(git_diff_from_buffer(&diff, text, strlen(text)));
+	cl_git_pass(diff_from_buffer(&diff, text, strlen(text)));
 	cl_git_pass(git_patch_from_diff(&patch, diff, 0));
 	cl_git_pass(git_patch_get_hunk(&hunk, &n, patch, 0));
 
@@ -393,7 +393,7 @@ void test_diff_parse__lineinfo(void)
 	const git_diff_hunk *hunk;
 	size_t n, l = 0;
 
-	cl_git_pass(git_diff_from_buffer(&diff, text, strlen(text)));
+	cl_git_pass(diff_from_buffer(&diff, text, strlen(text)));
 	cl_git_pass(git_patch_from_diff(&patch, diff, 0));
 	cl_git_pass(git_patch_get_hunk(&hunk, &n, patch, 0));
 
@@ -419,7 +419,7 @@ void test_diff_parse__new_file_with_space(void)
 	git_patch *patch;
 	git_diff *diff;
 
-	cl_git_pass(git_diff_from_buffer(&diff, content, strlen(content)));
+	cl_git_pass(diff_from_buffer(&diff, content, strlen(content)));
 	cl_git_pass(git_patch_from_diff((git_patch **) &patch, diff, 0));
 
 	cl_assert_equal_p(patch->diff_opts.old_prefix, NULL);
@@ -437,7 +437,7 @@ void test_diff_parse__new_file_with_space_and_regenerate_patch(void)
 	git_diff *diff = NULL;
 	git_buf buf = GIT_BUF_INIT;
 
-	cl_git_pass(git_diff_from_buffer(&diff, content, strlen(content)));
+	cl_git_pass(diff_from_buffer(&diff, content, strlen(content)));
 	cl_git_pass(git_diff_to_buf(&buf, diff, GIT_DIFF_FORMAT_PATCH));
 
 	git_buf_dispose(&buf);
@@ -450,7 +450,7 @@ void test_diff_parse__delete_file_with_space_and_regenerate_patch(void)
 	git_diff *diff = NULL;
 	git_buf buf = GIT_BUF_INIT;
 
-	cl_git_pass(git_diff_from_buffer(&diff, content, strlen(content)));
+	cl_git_pass(diff_from_buffer(&diff, content, strlen(content)));
 	cl_git_pass(git_diff_to_buf(&buf, diff, GIT_DIFF_FORMAT_PATCH));
 
 	git_buf_dispose(&buf);
@@ -464,7 +464,7 @@ void test_diff_parse__crlf(void)
 	git_patch *patch;
 	const git_diff_delta *delta;
 
-	cl_git_pass(git_diff_from_buffer(&diff, text, strlen(text)));
+	cl_git_pass(diff_from_buffer(&diff, text, strlen(text)));
 	cl_git_pass(git_patch_from_diff(&patch, diff, 0));
 	delta = git_patch_get_delta(patch);
 
diff --git a/tests/libgit2/diff/patchid.c b/tests/libgit2/diff/patchid.c
index 1cc368e21..91807e7b7 100644
--- a/tests/libgit2/diff/patchid.c
+++ b/tests/libgit2/diff/patchid.c
@@ -1,5 +1,6 @@
 #include "clar_libgit2.h"
 #include "patch/patch_common.h"
+#include "diff_helpers.h"
 
 static void verify_patch_id(const char *diff_content, const char *expected_id)
 {
@@ -7,7 +8,7 @@ static void verify_patch_id(const char *diff_content, const char *expected_id)
 	git_diff *diff;
 
 	cl_git_pass(git_oid__fromstr(&expected_oid, expected_id, GIT_OID_SHA1));
-	cl_git_pass(git_diff_from_buffer(&diff, diff_content, strlen(diff_content)));
+	cl_git_pass(diff_from_buffer(&diff, diff_content, strlen(diff_content)));
 	cl_git_pass(git_diff_patchid(&actual_oid, diff, NULL));
 
 	cl_assert_equal_oid(&expected_oid, &actual_oid);
diff --git a/tests/libgit2/diff/stats.c b/tests/libgit2/diff/stats.c
index b076ad5a9..7af891550 100644
--- a/tests/libgit2/diff/stats.c
+++ b/tests/libgit2/diff/stats.c
@@ -4,6 +4,7 @@
 #include "commit.h"
 #include "diff.h"
 #include "diff_generate.h"
+#include "diff_helpers.h"
 
 static git_repository *_repo;
 static git_diff_stats *_stats;
@@ -368,7 +369,7 @@ void test_diff_stats__new_file(void)
 	" 1 file changed, 1 insertion(+)\n"
 	" create mode 100644 Gurjeet Singh\n";
 
-	cl_git_pass(git_diff_from_buffer(&diff, input, strlen(input)));
+	cl_git_pass(diff_from_buffer(&diff, input, strlen(input)));
 	cl_git_pass(git_diff_get_stats(&_stats, diff));
 	cl_git_pass(git_diff_stats_to_buf(&buf, _stats, GIT_DIFF_STATS_FULL | GIT_DIFF_STATS_INCLUDE_SUMMARY, 0));
 	cl_assert_equal_s(stat, buf.ptr);