diff --git a/archive.c b/archive.c
index 295615580d..6cfb9e42d6 100644
--- a/archive.c
+++ b/archive.c
@@ -203,7 +203,7 @@ static void queue_directory(const unsigned char *sha1,
 	d->mode	   = mode;
 	c->bottom  = d;
 	d->len = xsnprintf(d->path, len, "%.*s%s/", (int)base->len, base->buf, filename);
-	hashcpy(d->oid.hash, sha1);
+	oidread(&d->oid, sha1);
 }
 
 static int write_directory(struct archiver_context *c)
diff --git a/builtin/fast-import.c b/builtin/fast-import.c
index 3afa81cf9a..9d2a058a66 100644
--- a/builtin/fast-import.c
+++ b/builtin/fast-import.c
@@ -1276,8 +1276,8 @@ static void load_tree(struct tree_entry *root)
 		e->versions[0].mode = e->versions[1].mode;
 		e->name = to_atom(c, strlen(c));
 		c += e->name->str_len + 1;
-		hashcpy(e->versions[0].oid.hash, (unsigned char *)c);
-		hashcpy(e->versions[1].oid.hash, (unsigned char *)c);
+		oidread(&e->versions[0].oid, (unsigned char *)c);
+		oidread(&e->versions[1].oid, (unsigned char *)c);
 		c += the_hash_algo->rawsz;
 	}
 	free(buf);
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 15507b5cff..41e2c240b8 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -524,7 +524,7 @@ static void *unpack_raw_entry(struct object_entry *obj,
 
 	switch (obj->type) {
 	case OBJ_REF_DELTA:
-		hashcpy(ref_oid->hash, fill(the_hash_algo->rawsz));
+		oidread(ref_oid, fill(the_hash_algo->rawsz));
 		use(the_hash_algo->rawsz);
 		break;
 	case OBJ_OFS_DELTA:
@@ -1358,7 +1358,7 @@ static struct object_entry *append_obj_to_pack(struct hashfile *f,
 	obj[1].idx.offset += write_compressed(f, buf, size);
 	obj[0].idx.crc32 = crc32_end(f);
 	hashflush(f);
-	hashcpy(obj->idx.oid.hash, sha1);
+	oidread(&obj->idx.oid, sha1);
 	return obj;
 }
 
diff --git a/builtin/unpack-objects.c b/builtin/unpack-objects.c
index 4a70b17f8f..a8b73ecf43 100644
--- a/builtin/unpack-objects.c
+++ b/builtin/unpack-objects.c
@@ -355,7 +355,7 @@ static void unpack_delta_entry(enum object_type type, unsigned long delta_size,
 	struct object_id base_oid;
 
 	if (type == OBJ_REF_DELTA) {
-		hashcpy(base_oid.hash, fill(the_hash_algo->rawsz));
+		oidread(&base_oid, fill(the_hash_algo->rawsz));
 		use(the_hash_algo->rawsz);
 		delta_data = get_data(delta_size);
 		if (dry_run || !delta_data) {
diff --git a/commit-graph.c b/commit-graph.c
index f18380b922..23fef56d31 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -425,7 +425,7 @@ struct commit_graph *parse_commit_graph(struct repository *r,
 		FREE_AND_NULL(graph->bloom_filter_settings);
 	}
 
-	hashcpy(graph->oid.hash, graph->data + graph->data_len - graph->hash_len);
+	oidread(&graph->oid, graph->data + graph->data_len - graph->hash_len);
 
 	if (verify_commit_graph_lite(graph))
 		goto free_and_return;
@@ -746,7 +746,7 @@ static void load_oid_from_graph(struct commit_graph *g,
 
 	lex_index = pos - g->num_commits_in_base;
 
-	hashcpy(oid->hash, g->chunk_oid_lookup + g->hash_len * lex_index);
+	oidread(oid, g->chunk_oid_lookup + g->hash_len * lex_index);
 }
 
 static struct commit_list **insert_parent_or_die(struct repository *r,
@@ -939,7 +939,7 @@ static struct tree *load_tree_for_commit(struct repository *r,
 	commit_data = g->chunk_commit_data +
 			GRAPH_DATA_WIDTH * (graph_pos - g->num_commits_in_base);
 
-	hashcpy(oid.hash, commit_data);
+	oidread(&oid, commit_data);
 	set_commit_tree(c, lookup_tree(r, &oid));
 
 	return c->maybe_tree;
@@ -2322,7 +2322,7 @@ int write_commit_graph(struct object_directory *odb,
 		struct commit_graph *g = ctx->r->objects->commit_graph;
 		for (i = 0; i < g->num_commits; i++) {
 			struct object_id oid;
-			hashcpy(oid.hash, g->chunk_oid_lookup + g->hash_len * i);
+			oidread(&oid, g->chunk_oid_lookup + g->hash_len * i);
 			oid_array_append(&ctx->oids, &oid);
 		}
 	}
@@ -2453,7 +2453,7 @@ int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
 	for (i = 0; i < g->num_commits; i++) {
 		struct commit *graph_commit;
 
-		hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
+		oidread(&cur_oid, g->chunk_oid_lookup + g->hash_len * i);
 
 		if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
 			graph_report(_("commit-graph has incorrect OID order: %s then %s"),
@@ -2501,7 +2501,7 @@ int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
 		timestamp_t generation;
 
 		display_progress(progress, i + 1);
-		hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
+		oidread(&cur_oid, g->chunk_oid_lookup + g->hash_len * i);
 
 		graph_commit = lookup_commit(r, &cur_oid);
 		odb_commit = (struct commit *)create_object(r, &cur_oid, alloc_commit_node(r));
diff --git a/dir.c b/dir.c
index 3474e67e8f..813dd7ba53 100644
--- a/dir.c
+++ b/dir.c
@@ -3344,7 +3344,7 @@ static void read_oid(size_t pos, void *cb)
 		rd->data = rd->end + 1;
 		return;
 	}
-	hashcpy(ud->exclude_oid.hash, rd->data);
+	oidread(&ud->exclude_oid, rd->data);
 	rd->data += the_hash_algo->rawsz;
 }
 
@@ -3352,7 +3352,7 @@ static void load_oid_stat(struct oid_stat *oid_stat, const unsigned char *data,
 			  const unsigned char *sha1)
 {
 	stat_data_from_disk(&oid_stat->stat, data);
-	hashcpy(oid_stat->oid.hash, sha1);
+	oidread(&oid_stat->oid, sha1);
 	oid_stat->valid = 1;
 }
 
diff --git a/http-walker.c b/http-walker.c
index 4fb1235cd4..90d8ecb57e 100644
--- a/http-walker.c
+++ b/http-walker.c
@@ -155,7 +155,7 @@ static void prefetch(struct walker *walker, unsigned char *sha1)
 
 	newreq = xmalloc(sizeof(*newreq));
 	newreq->walker = walker;
-	hashcpy(newreq->oid.hash, sha1);
+	oidread(&newreq->oid, sha1);
 	newreq->repo = data->alt;
 	newreq->state = WAITING;
 	newreq->req = NULL;
diff --git a/match-trees.c b/match-trees.c
index f6c194c1cc..df413989fa 100644
--- a/match-trees.c
+++ b/match-trees.c
@@ -226,7 +226,7 @@ static int splice_tree(const struct object_id *oid1, const char *prefix,
 		    oid_to_hex(oid1));
 	if (*subpath) {
 		struct object_id tree_oid;
-		hashcpy(tree_oid.hash, rewrite_here);
+		oidread(&tree_oid, rewrite_here);
 		status = splice_tree(&tree_oid, subpath, oid2, &subtree);
 		if (status)
 			return status;
diff --git a/midx.c b/midx.c
index 9e86583172..21d6a05e88 100644
--- a/midx.c
+++ b/midx.c
@@ -247,7 +247,7 @@ struct object_id *nth_midxed_object_oid(struct object_id *oid,
 	if (n >= m->num_objects)
 		return NULL;
 
-	hashcpy(oid->hash, m->chunk_oid_lookup + m->hash_len * n);
+	oidread(oid, m->chunk_oid_lookup + m->hash_len * n);
 	return oid;
 }
 
diff --git a/notes.c b/notes.c
index a19e4ad794..a44b25858f 100644
--- a/notes.c
+++ b/notes.c
@@ -352,7 +352,7 @@ static void add_non_note(struct notes_tree *t, char *path,
 	n->next = NULL;
 	n->path = path;
 	n->mode = mode;
-	hashcpy(n->oid.hash, sha1);
+	oidread(&n->oid, sha1);
 	t->prev_non_note = n;
 
 	if (!t->first_non_note) {
@@ -1134,7 +1134,7 @@ int remove_note(struct notes_tree *t, const unsigned char *object_sha1)
 	if (!t)
 		t = &default_notes_tree;
 	assert(t->initialized);
-	hashcpy(l.key_oid.hash, object_sha1);
+	oidread(&l.key_oid, object_sha1);
 	oidclr(&l.val_oid);
 	note_tree_remove(t, t->root, 0, &l);
 	if (is_null_oid(&l.val_oid)) /* no note was removed */
diff --git a/read-cache.c b/read-cache.c
index 5a907af2fb..2944146545 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1845,7 +1845,7 @@ static struct cache_entry *create_from_disk(struct mem_pool *ce_mem_pool,
 	ce->ce_flags = flags & ~CE_NAMEMASK;
 	ce->ce_namelen = len;
 	ce->index = 0;
-	hashcpy(ce->oid.hash, ondisk->data);
+	oidread(&ce->oid, ondisk->data);
 	memcpy(ce->name, name, len);
 	ce->name[len] = '\0';
 
@@ -2195,7 +2195,7 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)
 	if (verify_hdr(hdr, mmap_size) < 0)
 		goto unmap;
 
-	hashcpy(istate->oid.hash, (const unsigned char *)hdr + mmap_size - the_hash_algo->rawsz);
+	oidread(&istate->oid, (const unsigned char *)hdr + mmap_size - the_hash_algo->rawsz);
 	istate->version = ntohl(hdr->hdr_version);
 	istate->cache_nr = ntohl(hdr->hdr_entries);
 	istate->cache_alloc = alloc_nr(istate->cache_nr);
diff --git a/split-index.c b/split-index.c
index 94937d21a3..4d6e52d46f 100644
--- a/split-index.c
+++ b/split-index.c
@@ -21,7 +21,7 @@ int read_link_extension(struct index_state *istate,
 	if (sz < the_hash_algo->rawsz)
 		return error("corrupt link extension (too short)");
 	si = init_split_index(istate);
-	hashcpy(si->base_oid.hash, data);
+	oidread(&si->base_oid, data);
 	data += the_hash_algo->rawsz;
 	sz -= the_hash_algo->rawsz;
 	if (!sz)
diff --git a/tree-walk.c b/tree-walk.c
index 2d6226d5f1..3a94959d64 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -49,7 +49,7 @@ static int decode_tree_entry(struct tree_desc *desc, const char *buf, unsigned l
 	desc->entry.path = path;
 	desc->entry.mode = canon_mode(mode);
 	desc->entry.pathlen = len - 1;
-	hashcpy(desc->entry.oid.hash, (const unsigned char *)path + len);
+	oidread(&desc->entry.oid, (const unsigned char *)path + len);
 
 	return 0;
 }