diff --git a/Makefile b/Makefile
index ef1ff2228f..dc356ce4dd 100644
--- a/Makefile
+++ b/Makefile
@@ -738,7 +738,7 @@ TEST_BUILTINS_OBJS += test-run-command.o
 TEST_BUILTINS_OBJS += test-scrap-cache-tree.o
 TEST_BUILTINS_OBJS += test-serve-v2.o
 TEST_BUILTINS_OBJS += test-sha1.o
-TEST_BUILTINS_OBJS += test-sha1-array.o
+TEST_BUILTINS_OBJS += test-oid-array.o
 TEST_BUILTINS_OBJS += test-sha256.o
 TEST_BUILTINS_OBJS += test-sigchain.o
 TEST_BUILTINS_OBJS += test-strcmp-offset.o
@@ -929,6 +929,7 @@ LIB_OBJS += notes-utils.o
 LIB_OBJS += object.o
 LIB_OBJS += oidmap.o
 LIB_OBJS += oidset.o
+LIB_OBJS += oid-array.o
 LIB_OBJS += packfile.o
 LIB_OBJS += pack-bitmap.o
 LIB_OBJS += pack-bitmap-write.o
@@ -978,7 +979,6 @@ LIB_OBJS += sequencer.o
 LIB_OBJS += serve.o
 LIB_OBJS += server-info.o
 LIB_OBJS += setup.o
-LIB_OBJS += sha1-array.o
 LIB_OBJS += sha1-lookup.o
 LIB_OBJS += sha1-file.o
 LIB_OBJS += sha1-name.o
diff --git a/bisect.c b/bisect.c
index 9154f810f7..d5e830410f 100644
--- a/bisect.c
+++ b/bisect.c
@@ -10,7 +10,7 @@
 #include "run-command.h"
 #include "log-tree.h"
 #include "bisect.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "argv-array.h"
 #include "commit-slab.h"
 #include "commit-reach.h"
@@ -473,7 +473,7 @@ static void read_bisect_paths(struct argv_array *array)
 	fclose(fp);
 }
 
-static char *join_sha1_array_hex(struct oid_array *array, char delim)
+static char *join_oid_array_hex(struct oid_array *array, char delim)
 {
 	struct strbuf joined_hexs = STRBUF_INIT;
 	int i;
@@ -765,7 +765,7 @@ static enum bisect_error handle_bad_merge_base(void)
 {
 	if (is_expected_rev(current_bad_oid)) {
 		char *bad_hex = oid_to_hex(current_bad_oid);
-		char *good_hex = join_sha1_array_hex(&good_revs, ' ');
+		char *good_hex = join_oid_array_hex(&good_revs, ' ');
 		if (!strcmp(term_bad, "bad") && !strcmp(term_good, "good")) {
 			fprintf(stderr, _("The merge base %s is bad.\n"
 				"This means the bug has been fixed "
@@ -796,7 +796,7 @@ static void handle_skipped_merge_base(const struct object_id *mb)
 {
 	char *mb_hex = oid_to_hex(mb);
 	char *bad_hex = oid_to_hex(current_bad_oid);
-	char *good_hex = join_sha1_array_hex(&good_revs, ' ');
+	char *good_hex = join_oid_array_hex(&good_revs, ' ');
 
 	warning(_("the merge base between %s and [%s] "
 		"must be skipped.\n"
diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index 6ecc8ee6dc..0d03fdac6e 100644
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@ -12,7 +12,7 @@
 #include "userdiff.h"
 #include "streaming.h"
 #include "tree-walk.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "packfile.h"
 #include "object-store.h"
 #include "promisor-remote.h"
diff --git a/builtin/diff.c b/builtin/diff.c
index 42ac803091..8537b17bd5 100644
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -17,7 +17,7 @@
 #include "log-tree.h"
 #include "builtin.h"
 #include "submodule.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 
 #define DIFF_NO_INDEX_EXPLICIT 1
 #define DIFF_NO_INDEX_IMPLICIT 2
diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c
index dc1485c8aa..4771100072 100644
--- a/builtin/fetch-pack.c
+++ b/builtin/fetch-pack.c
@@ -3,7 +3,7 @@
 #include "fetch-pack.h"
 #include "remote.h"
 #include "connect.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "protocol.h"
 
 static const char fetch_pack_usage[] =
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index dc7c58ce3f..fdd18c7ccb 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -26,7 +26,7 @@
 #include "pack-bitmap.h"
 #include "delta-islands.h"
 #include "reachable.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "argv-array.h"
 #include "list.h"
 #include "packfile.h"
diff --git a/builtin/pull.c b/builtin/pull.c
index ef0baa0fe2..b5d51ea74f 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -12,7 +12,7 @@
 #include "parse-options.h"
 #include "exec-cmd.h"
 #include "run-command.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "remote.h"
 #include "dir.h"
 #include "rebase.h"
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 2cc18bbffd..d46147f709 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -13,7 +13,7 @@
 #include "remote.h"
 #include "connect.h"
 #include "string-list.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "connected.h"
 #include "argv-array.h"
 #include "version.h"
diff --git a/builtin/send-pack.c b/builtin/send-pack.c
index 098ebf22d0..f2c5a34402 100644
--- a/builtin/send-pack.c
+++ b/builtin/send-pack.c
@@ -11,7 +11,7 @@
 #include "quote.h"
 #include "transport.h"
 #include "version.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "gpg-interface.h"
 #include "gettext.h"
 #include "protocol.h"
diff --git a/builtin/tag.c b/builtin/tag.c
index cc30d346f5..dd160b49c7 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -17,7 +17,7 @@
 #include "diff.h"
 #include "revision.h"
 #include "gpg-interface.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "column.h"
 #include "ref-filter.h"
 
diff --git a/cache.h b/cache.h
index c77b95870a..0f0485ecfe 100644
--- a/cache.h
+++ b/cache.h
@@ -14,7 +14,7 @@
 #include "pack-revindex.h"
 #include "hash.h"
 #include "path.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "repository.h"
 #include "mem-pool.h"
 
diff --git a/combine-diff.c b/combine-diff.c
index d5c4d839dc..002e0e5438 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -10,7 +10,7 @@
 #include "log-tree.h"
 #include "refs.h"
 #include "userdiff.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "revision.h"
 
 static int compare_paths(const struct combine_diff_path *one,
diff --git a/connect.c b/connect.c
index b6451ab5e8..23013c6344 100644
--- a/connect.c
+++ b/connect.c
@@ -9,7 +9,7 @@
 #include "connect.h"
 #include "url.h"
 #include "string-list.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "transport.h"
 #include "strbuf.h"
 #include "version.h"
diff --git a/delta-islands.c b/delta-islands.c
index 09dbd3cf72..aa98b2e541 100644
--- a/delta-islands.c
+++ b/delta-islands.c
@@ -17,7 +17,7 @@
 #include "pack-bitmap.h"
 #include "pack-objects.h"
 #include "delta-islands.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "config.h"
 
 KHASH_INIT(str, const char *, void *, 1, kh_str_hash_func, kh_str_hash_equal)
diff --git a/fetch-pack.c b/fetch-pack.c
index 1734a573b0..0b07b3ee73 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -15,7 +15,7 @@
 #include "connect.h"
 #include "transport.h"
 #include "version.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "oidset.h"
 #include "packfile.h"
 #include "object-store.h"
diff --git a/object-store.h b/object-store.h
index be72fee7d5..d1e490f203 100644
--- a/object-store.h
+++ b/object-store.h
@@ -4,7 +4,7 @@
 #include "cache.h"
 #include "oidmap.h"
 #include "list.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "strbuf.h"
 #include "thread-utils.h"
 
diff --git a/sha1-array.c b/oid-array.c
similarity index 93%
rename from sha1-array.c
rename to oid-array.c
index 3eeadfede9..8657a5cedf 100644
--- a/sha1-array.c
+++ b/oid-array.c
@@ -1,5 +1,5 @@
 #include "cache.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "sha1-lookup.h"
 
 void oid_array_append(struct oid_array *array, const struct object_id *oid)
@@ -46,9 +46,9 @@ int oid_array_for_each(struct oid_array *array,
 		       for_each_oid_fn fn,
 		       void *data)
 {
-	int i;
+	size_t i;
 
-	/* No oid_array_sort() here! See sha1-array.h */
+	/* No oid_array_sort() here! See oid-array.h */
 
 	for (i = 0; i < array->nr; i++) {
 		int ret = fn(array->oid + i, data);
@@ -62,7 +62,7 @@ int oid_array_for_each_unique(struct oid_array *array,
 			      for_each_oid_fn fn,
 			      void *data)
 {
-	int i;
+	size_t i;
 
 	if (!array->sorted)
 		oid_array_sort(array);
@@ -82,7 +82,7 @@ void oid_array_filter(struct oid_array *array,
 		      for_each_oid_fn want,
 		      void *cb_data)
 {
-	unsigned nr = array->nr, src, dst;
+	size_t nr = array->nr, src, dst;
 	struct object_id *oids = array->oid;
 
 	for (src = dst = 0; src < nr; src++) {
diff --git a/sha1-array.h b/oid-array.h
similarity index 97%
rename from sha1-array.h
rename to oid-array.h
index dc1bca9c9a..f28d322c90 100644
--- a/sha1-array.h
+++ b/oid-array.h
@@ -19,7 +19,7 @@
  *
  * void some_func(void)
  * {
- *     struct sha1_array hashes = OID_ARRAY_INIT;
+ *     struct oid_array hashes = OID_ARRAY_INIT;
  *     struct object_id oid;
  *
  *     // Read objects into our set
@@ -49,8 +49,8 @@
  */
 struct oid_array {
 	struct object_id *oid;
-	int nr;
-	int alloc;
+	size_t nr;
+	size_t alloc;
 	int sorted;
 };
 
diff --git a/oidset.h b/oidset.h
index d8a106b127..3a2d9d1115 100644
--- a/oidset.h
+++ b/oidset.h
@@ -4,7 +4,7 @@
 #include "khash.h"
 
 /**
- * This API is similar to sha1-array, in that it maintains a set of object ids
+ * This API is similar to oid-array, in that it maintains a set of object ids
  * in a memory-efficient way. The major differences are:
  *
  *   1. It uses a hash, so we can do online duplicate removal, rather than
diff --git a/parse-options-cb.c b/parse-options-cb.c
index a28b55be48..86cd393013 100644
--- a/parse-options-cb.c
+++ b/parse-options-cb.c
@@ -5,7 +5,7 @@
 #include "color.h"
 #include "string-list.h"
 #include "argv-array.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 
 /*----- some often used options -----*/
 
diff --git a/ref-filter.c b/ref-filter.c
index b1812cb69a..35776838f4 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -1976,10 +1976,9 @@ static int for_each_fullref_in_pattern(struct ref_filter *filter,
 }
 
 /*
- * Given a ref (sha1, refname), check if the ref belongs to the array
- * of sha1s. If the given ref is a tag, check if the given tag points
- * at one of the sha1s in the given sha1 array.
- * the given sha1_array.
+ * Given a ref (oid, refname), check if the ref belongs to the array
+ * of oids. If the given ref is a tag, check if the given tag points
+ * at one of the oids in the given oid array.
  * NEEDSWORK:
  * 1. Only a single level of inderection is obtained, we might want to
  * change this to account for multiple levels (e.g. annotated tags
diff --git a/ref-filter.h b/ref-filter.h
index f1dcff4c6e..64330e9601 100644
--- a/ref-filter.h
+++ b/ref-filter.h
@@ -1,7 +1,7 @@
 #ifndef REF_FILTER_H
 #define REF_FILTER_H
 
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "refs.h"
 #include "commit.h"
 #include "parse-options.h"
diff --git a/remote-curl.c b/remote-curl.c
index e4cd321844..1c9aa3d0ab 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -12,7 +12,7 @@
 #include "sideband.h"
 #include "argv-array.h"
 #include "credential.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "send-pack.h"
 #include "protocol.h"
 #include "quote.h"
diff --git a/send-pack.c b/send-pack.c
index 0407841ae8..da4741ce4a 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -12,7 +12,7 @@
 #include "quote.h"
 #include "transport.h"
 #include "version.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "gpg-interface.h"
 #include "cache.h"
 
diff --git a/sha1-name.c b/sha1-name.c
index 5bb006e5a9..6561cd9097 100644
--- a/sha1-name.c
+++ b/sha1-name.c
@@ -8,7 +8,7 @@
 #include "refs.h"
 #include "remote.h"
 #include "dir.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "packfile.h"
 #include "object-store.h"
 #include "repository.h"
diff --git a/shallow.c b/shallow.c
index 7fd04afed1..14f7fa6e27 100644
--- a/shallow.c
+++ b/shallow.c
@@ -8,7 +8,7 @@
 #include "pkt-line.h"
 #include "remote.h"
 #include "refs.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "diff.h"
 #include "revision.h"
 #include "commit-slab.h"
diff --git a/submodule.c b/submodule.c
index c3aadf3fff..e2ef5698c8 100644
--- a/submodule.c
+++ b/submodule.c
@@ -12,7 +12,7 @@
 #include "diffcore.h"
 #include "refs.h"
 #include "string-list.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "argv-array.h"
 #include "blob.h"
 #include "thread-utils.h"
diff --git a/t/helper/test-sha1-array.c b/t/helper/test-oid-array.c
similarity index 83%
rename from t/helper/test-sha1-array.c
rename to t/helper/test-oid-array.c
index ad5e69f9d3..ce9fd5f091 100644
--- a/t/helper/test-sha1-array.c
+++ b/t/helper/test-oid-array.c
@@ -1,6 +1,6 @@
 #include "test-tool.h"
 #include "cache.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 
 static int print_oid(const struct object_id *oid, void *data)
 {
@@ -8,7 +8,7 @@ static int print_oid(const struct object_id *oid, void *data)
 	return 0;
 }
 
-int cmd__sha1_array(int argc, const char **argv)
+int cmd__oid_array(int argc, const char **argv)
 {
 	struct oid_array array = OID_ARRAY_INIT;
 	struct strbuf line = STRBUF_INIT;
@@ -19,11 +19,11 @@ int cmd__sha1_array(int argc, const char **argv)
 
 		if (skip_prefix(line.buf, "append ", &arg)) {
 			if (get_oid_hex(arg, &oid))
-				die("not a hexadecimal SHA1: %s", arg);
+				die("not a hexadecimal oid: %s", arg);
 			oid_array_append(&array, &oid);
 		} else if (skip_prefix(line.buf, "lookup ", &arg)) {
 			if (get_oid_hex(arg, &oid))
-				die("not a hexadecimal SHA1: %s", arg);
+				die("not a hexadecimal oid: %s", arg);
 			printf("%d\n", oid_array_lookup(&array, &oid));
 		} else if (!strcmp(line.buf, "clear"))
 			oid_array_clear(&array);
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index 5f395972c0..2ece4d1ebf 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -37,6 +37,7 @@ static struct test_cmd cmds[] = {
 	{ "match-trees", cmd__match_trees },
 	{ "mergesort", cmd__mergesort },
 	{ "mktemp", cmd__mktemp },
+	{ "oid-array", cmd__oid_array },
 	{ "oidmap", cmd__oidmap },
 	{ "online-cpus", cmd__online_cpus },
 	{ "parse-options", cmd__parse_options },
@@ -57,7 +58,6 @@ static struct test_cmd cmds[] = {
 	{ "scrap-cache-tree", cmd__scrap_cache_tree },
 	{ "serve-v2", cmd__serve_v2 },
 	{ "sha1", cmd__sha1 },
-	{ "sha1-array", cmd__sha1_array },
 	{ "sha256", cmd__sha256 },
 	{ "sigchain", cmd__sigchain },
 	{ "strcmp-offset", cmd__strcmp_offset },
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index 4eb5e6609e..1cbaec02f3 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -47,7 +47,7 @@ int cmd__run_command(int argc, const char **argv);
 int cmd__scrap_cache_tree(int argc, const char **argv);
 int cmd__serve_v2(int argc, const char **argv);
 int cmd__sha1(int argc, const char **argv);
-int cmd__sha1_array(int argc, const char **argv);
+int cmd__oid_array(int argc, const char **argv);
 int cmd__sha256(int argc, const char **argv);
 int cmd__sigchain(int argc, const char **argv);
 int cmd__strcmp_offset(int argc, const char **argv);
diff --git a/t/t0064-sha1-array.sh b/t/t0064-sha1-array.sh
index 5dda570b9a..45685af2fd 100755
--- a/t/t0064-sha1-array.sh
+++ b/t/t0064-sha1-array.sh
@@ -18,7 +18,7 @@ test_expect_success 'ordered enumeration' '
 	{
 		echoid append 88 44 aa 55 &&
 		echo for_each_unique
-	} | test-tool sha1-array >actual &&
+	} | test-tool oid-array >actual &&
 	test_cmp expect actual
 '
 
@@ -28,7 +28,7 @@ test_expect_success 'ordered enumeration with duplicate suppression' '
 		echoid append 88 44 aa 55 &&
 		echoid append 88 44 aa 55 &&
 		echo for_each_unique
-	} | test-tool sha1-array >actual &&
+	} | test-tool oid-array >actual &&
 	test_cmp expect actual
 '
 
@@ -36,7 +36,7 @@ test_expect_success 'lookup' '
 	{
 		echoid append 88 44 aa 55 &&
 		echoid lookup 55
-	} | test-tool sha1-array >actual &&
+	} | test-tool oid-array >actual &&
 	n=$(cat actual) &&
 	test "$n" -eq 1
 '
@@ -45,7 +45,7 @@ test_expect_success 'lookup non-existing entry' '
 	{
 		echoid append 88 44 aa 55 &&
 		echoid lookup 33
-	} | test-tool sha1-array >actual &&
+	} | test-tool oid-array >actual &&
 	n=$(cat actual) &&
 	test "$n" -lt 0
 '
@@ -55,7 +55,7 @@ test_expect_success 'lookup with duplicates' '
 		echoid append 88 44 aa 55 &&
 		echoid append 88 44 aa 55 &&
 		echoid lookup 55
-	} | test-tool sha1-array >actual &&
+	} | test-tool oid-array >actual &&
 	n=$(cat actual) &&
 	test "$n" -ge 2 &&
 	test "$n" -le 3
@@ -66,7 +66,7 @@ test_expect_success 'lookup non-existing entry with duplicates' '
 		echoid append 88 44 aa 55 &&
 		echoid append 88 44 aa 55 &&
 		echoid lookup 66
-	} | test-tool sha1-array >actual &&
+	} | test-tool oid-array >actual &&
 	n=$(cat actual) &&
 	test "$n" -lt 0
 '
@@ -81,7 +81,7 @@ test_expect_success 'lookup with almost duplicate values' '
 		echo "append $id1" &&
 		echo "append $id2" &&
 		echoid lookup 55
-	} | test-tool sha1-array >actual &&
+	} | test-tool oid-array >actual &&
 	n=$(cat actual) &&
 	test "$n" -eq 0
 '
@@ -90,7 +90,7 @@ test_expect_success 'lookup with single duplicate value' '
 	{
 		echoid append 55 55 &&
 		echoid lookup 55
-	} | test-tool sha1-array >actual &&
+	} | test-tool oid-array >actual &&
 	n=$(cat actual) &&
 	test "$n" -ge 0 &&
 	test "$n" -le 1
diff --git a/transport.c b/transport.c
index 1fdc7dac1a..471c5bd339 100644
--- a/transport.c
+++ b/transport.c
@@ -16,7 +16,7 @@
 #include "url.h"
 #include "submodule.h"
 #include "string-list.h"
-#include "sha1-array.h"
+#include "oid-array.h"
 #include "sigchain.h"
 #include "transport-internal.h"
 #include "protocol.h"