diff --git a/builtin/blame.c b/builtin/blame.c
index 126b8c9e5ba627ee5514f5a472bd7ae5cb9f9f67..cffc62654084b025ffbdb947448fa86c81dc6442 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -1901,7 +1901,7 @@ static void emit_porcelain(struct scoreboard *sb, struct blame_entry *ent,
 	struct origin *suspect = ent->suspect;
 	char hex[GIT_SHA1_HEXSZ + 1];
 
-	sha1_to_hex_r(hex, suspect->commit->object.oid.hash);
+	oid_to_hex_r(hex, &suspect->commit->object.oid);
 	printf("%s %d %d %d\n",
 	       hex,
 	       ent->s_lno + 1,
@@ -1941,7 +1941,7 @@ static void emit_other(struct scoreboard *sb, struct blame_entry *ent, int opt)
 	int show_raw_time = !!(opt & OUTPUT_RAW_TIMESTAMP);
 
 	get_commit_info(suspect->commit, &ci, 1);
-	sha1_to_hex_r(hex, suspect->commit->object.oid.hash);
+	oid_to_hex_r(hex, &suspect->commit->object.oid);
 
 	cp = nth_line(sb, ent->lno);
 	for (cnt = 0; cnt < ent->num_lines; cnt++) {
diff --git a/builtin/checkout.c b/builtin/checkout.c
index bfe685c198cd38b59ffe66fa6b3d3a7bced60824..80d5e389813bed951b63ae5bd8e4347af4da53df 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -56,8 +56,8 @@ static int post_checkout_hook(struct commit *old, struct commit *new,
 			      int changed)
 {
 	return run_hook_le(NULL, "post-checkout",
-			   sha1_to_hex(old ? old->object.oid.hash : null_sha1),
-			   sha1_to_hex(new ? new->object.oid.hash : null_sha1),
+			   oid_to_hex(old ? &old->object.oid : &null_oid),
+			   oid_to_hex(new ? &new->object.oid : &null_oid),
 			   changed ? "1" : "0", NULL);
 	/* "new" can be NULL when checking out from the index before
 	   a commit exists. */
diff --git a/builtin/merge-index.c b/builtin/merge-index.c
index ce356b1da126e31b4ef78b29dcc49246881b6a59..2d1b6db6bd7a33f838a50deceb108ee1ad468db1 100644
--- a/builtin/merge-index.c
+++ b/builtin/merge-index.c
@@ -22,7 +22,7 @@ static int merge_entry(int pos, const char *path)
 		if (strcmp(ce->name, path))
 			break;
 		found++;
-		sha1_to_hex_r(hexbuf[stage], ce->oid.hash);
+		oid_to_hex_r(hexbuf[stage], &ce->oid);
 		xsnprintf(ownbuf[stage], sizeof(ownbuf[stage]), "%o", ce->ce_mode);
 		arguments[stage] = hexbuf[stage];
 		arguments[stage + 4] = ownbuf[stage];
diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index c43decda70112a9cdb7789dc81394286459aa3af..0aa93d58919742852b05b952e8e35b5270f74ba8 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -237,7 +237,7 @@ static int show_bisect_vars(struct rev_list_info *info, int reaches, int all)
 		cnt = reaches;
 
 	if (revs->commits)
-		sha1_to_hex_r(hex, revs->commits->item->object.oid.hash);
+		oid_to_hex_r(hex, &revs->commits->item->object.oid);
 
 	if (flags & BISECT_SHOW_ALL) {
 		traverse_commit_list(revs, show_commit, show_object, info);
diff --git a/diff.c b/diff.c
index f08cd8e033d104253a4b120f70cb188e39ef9aee..d91a344908abe7335eaffef4157fc59fefdf3815 100644
--- a/diff.c
+++ b/diff.c
@@ -3015,7 +3015,7 @@ static struct diff_tempfile *prepare_temp_file(const char *name,
 			if (!one->oid_valid)
 				sha1_to_hex_r(temp->hex, null_sha1);
 			else
-				sha1_to_hex_r(temp->hex, one->oid.hash);
+				oid_to_hex_r(temp->hex, &one->oid);
 			/* Even though we may sometimes borrow the
 			 * contents from the work tree, we always want
 			 * one->mode.  mode is trustworthy even when
diff --git a/refs/files-backend.c b/refs/files-backend.c
index f9023939d5884e0f975d5997336313695e407ca1..8ee2aba39f2b0bae36e66bc65610b429543bc1d8 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -697,7 +697,7 @@ static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator,
 
 	if (peel_entry(entry, 0))
 		return -1;
-	hashcpy(peeled->hash, entry->u.value.peeled.hash);
+	oidcpy(peeled, &entry->u.value.peeled);
 	return 0;
 }
 
diff --git a/wt-status.c b/wt-status.c
index 4dff0b3e2108bbd41e638c7beb69e62b20fa8740..d47012048f81c92a82758d87f8726cb919501104 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -628,7 +628,7 @@ static void wt_status_collect_changes_initial(struct wt_status *s)
 			d->index_status = DIFF_STATUS_ADDED;
 			/* Leave {mode,oid}_head zero for adds. */
 			d->mode_index = ce->ce_mode;
-			hashcpy(d->oid_index.hash, ce->oid.hash);
+			oidcpy(&d->oid_index, &ce->oid);
 		}
 	}
 }
@@ -2102,7 +2102,7 @@ static void wt_porcelain_v2_print_unmerged_entry(
 		if (strcmp(ce->name, it->string) || !stage)
 			break;
 		stages[stage - 1].mode = ce->ce_mode;
-		hashcpy(stages[stage - 1].oid.hash, ce->oid.hash);
+		oidcpy(&stages[stage - 1].oid, &ce->oid);
 		sum |= (1 << (stage - 1));
 	}
 	if (sum != d->stagemask)