diff --git a/builtin/log.c b/builtin/log.c
index 37d4e2562c199f..3b2cc034c594da 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -648,6 +648,9 @@ int cmd_show(int argc, const char **argv, const char *prefix)
 	init_log_defaults();
 	git_config(git_log_config, NULL);
 
+	prepare_repo_settings(the_repository);
+	the_repository->settings.command_requires_full_index = 0;
+
 	memset(&match_all, 0, sizeof(match_all));
 	repo_init_revisions(the_repository, &rev, prefix);
 	rev.diff = 1;
diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh
index ed71042acbadd3..6974c42dbdd448 100755
--- a/t/t1092-sparse-checkout-compatibility.sh
+++ b/t/t1092-sparse-checkout-compatibility.sh
@@ -1164,6 +1164,34 @@ test_expect_success 'clean' '
 	test_sparse_match test_path_is_dir folder1
 '
 
+test_expect_success 'show (cached blobs/trees)' '
+	init_repos &&
+
+	test_all_match git show :a &&
+	test_all_match git show :deep/a &&
+	test_sparse_match git show :folder1/a &&
+
+	# Asking "git show" for directories in the index
+	# does not work as implemented. The error message is
+	# different for a full checkout and a sparse checkout
+	# when the directory is outside of the cone.
+	test_all_match test_must_fail git show :deep/ &&
+	test_must_fail git -C full-checkout show :folder1/ &&
+	test_must_fail git -C sparse-checkout show :folder1/ &&
+
+	# The sparse index actually has "folder1" inside, so
+	# "git show :folder1/" succeeds when it did not before.
+	git -C sparse-index show :folder1/ >actual &&
+	git -C sparse-index show HEAD:folder1 >expect &&
+
+	# The output of "git show" includes the way we
+	# referenced the objects, so strip that out.
+	test_line_count = 4 actual &&
+	tail -n 2 actual >actual-trunc &&
+	tail -n 2 expect >expect-trunc &&
+	test_cmp expect-trunc actual-trunc
+'
+
 test_expect_success 'submodule handling' '
 	init_repos &&
 
@@ -1278,6 +1306,9 @@ test_expect_success 'sparse-index is not expanded' '
 	echo >>sparse-index/untracked.txt &&
 	ensure_not_expanded add . &&
 
+	ensure_not_expanded show :a &&
+	ensure_not_expanded show :deep/a &&
+
 	echo >>sparse-index/a &&
 	ensure_not_expanded stash &&
 	ensure_not_expanded stash list &&