1 files changed, 122 insertions, 0 deletions
diff --git a/t/t7418-submodule-sparse-gitmodules.sh b/t/t7418-submodule-sparse-gitmodules.sh
new file mode 100755
index 0000000000..3f7f271883
--- /dev/null
+++ b/t/t7418-submodule-sparse-gitmodules.sh
@@ -0,0 +1,122 @@
+#!/bin/sh
+#
+# Copyright (C) 2018  Antonio Ospite <ao2@ao2.it>
+#
+
+test_description='Test reading/writing .gitmodules when not in the working tree
+
+This test verifies that, when .gitmodules is in the current branch but is not
+in the working tree reading from it still works but writing to it does not.
+
+The test setup uses a sparse checkout, however the same scenario can be set up
+also by committing .gitmodules and then just removing it from the filesystem.
+'
+
+. ./test-lib.sh
+
+test_expect_success 'sparse checkout setup which hides .gitmodules' '
+	git init upstream &&
+	git init submodule &&
+	(cd submodule &&
+		echo file >file &&
+		git add file &&
+		test_tick &&
+		git commit -m "Add file"
+	) &&
+	(cd upstream &&
+		git submodule add ../submodule &&
+		test_tick &&
+		git commit -m "Add submodule"
+	) &&
+	git clone upstream super &&
+	(cd super &&
+		cat >.git/info/sparse-checkout <<-\EOF &&
+		/*
+		!/.gitmodules
+		EOF
+		git config core.sparsecheckout true &&
+		git read-tree -m -u HEAD &&
+		test_path_is_missing .gitmodules
+	)
+'
+
+test_expect_success 'reading gitmodules config file when it is not checked out' '
+	echo "../submodule" >expect &&
+	git -C super submodule--helper config submodule.submodule.url >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'not writing gitmodules config file when it is not checked out' '
+	test_must_fail git -C super submodule--helper config submodule.submodule.url newurl &&
+	test_path_is_missing super/.gitmodules
+'
+
+test_expect_success 'initialising submodule when the gitmodules config is not checked out' '
+	test_must_fail git -C super config submodule.submodule.url &&
+	git -C super submodule init &&
+	git -C super config submodule.submodule.url >actual &&
+	echo "$(pwd)/submodule" >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success 'updating submodule when the gitmodules config is not checked out' '
+	test_path_is_missing super/submodule/file &&
+	git -C super submodule update &&
+	test_cmp submodule/file super/submodule/file
+'
+
+ORIG_SUBMODULE=$(git -C submodule rev-parse HEAD)
+ORIG_UPSTREAM=$(git -C upstream rev-parse HEAD)
+ORIG_SUPER=$(git -C super rev-parse HEAD)
+
+test_expect_success 're-updating submodule when the gitmodules config is not checked out' '
+	test_when_finished "git -C submodule reset --hard $ORIG_SUBMODULE;
+			    git -C upstream reset --hard $ORIG_UPSTREAM;
+			    git -C super reset --hard $ORIG_SUPER;
+			    git -C upstream submodule update --remote;
+			    git -C super pull;
+			    git -C super submodule update --remote" &&
+	(cd submodule &&
+		echo file2 >file2 &&
+		git add file2 &&
+		test_tick &&
+		git commit -m "Add file2 to submodule"
+	) &&
+	(cd upstream &&
+		git submodule update --remote &&
+		git add submodule &&
+		test_tick &&
+		git commit -m "Update submodule"
+	) &&
+	git -C super pull &&
+	# The --for-status options reads the gitmodules config
+	git -C super submodule summary --for-status >actual &&
+	rev1=$(git -C submodule rev-parse --short HEAD) &&
+	rev2=$(git -C submodule rev-parse --short HEAD^) &&
+	cat >expect <<-EOF &&
+	* submodule ${rev1}...${rev2} (1):
+	  < Add file2 to submodule
+
+	EOF
+	test_cmp expect actual &&
+	# Test that the update actually succeeds
+	test_path_is_missing super/submodule/file2 &&
+	git -C super submodule update &&
+	test_cmp submodule/file2 super/submodule/file2 &&
+	git -C super status --short >output &&
+	test_must_be_empty output
+'
+
+test_expect_success 'not adding submodules when the gitmodules config is not checked out' '
+	git clone submodule new_submodule &&
+	test_must_fail git -C super submodule add ../new_submodule &&
+	test_path_is_missing .gitmodules
+'
+
+# This test checks that the previous "git submodule add" did not leave the
+# repository in a spurious state when it failed.
+test_expect_success 'init submodule still works even after the previous add failed' '
+	git -C super submodule init
+'
+
+test_done