[RFC PATCH 10/10] t7415: add new test about using HEAD:.gitmodules from the index

[Antonio Ospite <ao2@ao2.it>]

git submodule commands can now access .gitmodules from the index when
it's not checked out in the work tree, add some tests for that scenario.

Signed-off-by: Antonio Ospite <ao2@ao2.it>
---
 t/t7415-submodule-sparse-gitmodules.sh | 124 +++++++++++++++++++++++++
 1 file changed, 124 insertions(+)
 create mode 100755 t/t7415-submodule-sparse-gitmodules.sh

diff --git a/t/t7415-submodule-sparse-gitmodules.sh b/t/t7415-submodule-sparse-gitmodules.sh
new file mode 100755
index 000000000..3ae269b3a
--- /dev/null
+++ b/t/t7415-submodule-sparse-gitmodules.sh
@@ -0,0 +1,124 @@
+#!/bin/sh
+#
+# Copyright (C) 2018  Antonio Ospite <ao2@ao2.it>
+#
+
+test_description=' Test reading/writing the gitmodules config file when not checked out
+
+This test verifies that reading the gitmodules config file from the index when
+it is not checked out works, and that writing to it does not.
+'
+
+. ./test-lib.sh
+
+test_expect_success 'sparse checkout setup which hides .gitmodules' '
+	echo file > file &&
+	git add file &&
+	test_tick &&
+	git commit -m upstream &&
+	git clone . super &&
+	git clone super submodule &&
+	git clone super new_submodule &&
+	(cd super &&
+		git submodule add ../submodule
+		test_tick &&
+		git commit -m submodule &&
+		cat >.git/info/sparse-checkout <<\EOF &&
+/*
+!/.gitmodules
+EOF
+		git config core.sparsecheckout true &&
+		git read-tree -m -u HEAD &&
+		test ! -e .gitmodules
+	)
+'
+
+test_expect_success 'reading gitmodules config file when it is not checked out' '
+	(cd super &&
+		echo "../submodule" >expected &&
+		git submodule--helper config submodule.submodule.url >actual &&
+		test_cmp expected actual
+	)
+'
+
+test_expect_success 'not writing gitmodules config file when it is not checked out' '
+	(cd super &&
+		test_must_fail git submodule--helper config submodule.submodule.url newurl
+	)
+'
+
+test_expect_success 'not staging gitmodules config when it is not checked out' '
+	(cd super &&
+		test_must_fail git submodule--helper config --stage
+	)
+'
+
+test_expect_success 'not even staging manually crafted .gitmodules when it is not supposed to be checked out' '
+	(cd super &&
+		echo "bogus content" > .gitmodules &&
+		test_must_fail git submodule--helper config --stage &&
+		rm .gitmodules
+	)
+'
+
+test_expect_success 'initialising submodule when the gitmodules config is not checked out' '
+	(cd super &&
+		git submodule init
+	)
+'
+
+test_expect_success 'showing submodule summary when the gitmodules config is not checked out' '
+	(cd super &&
+		git submodule summary
+	)
+'
+
+test_expect_success 'updating submodule when the gitmodules config is not checked out' '
+	(cd submodule &&
+		echo file2 >file2 &&
+		git add file2 &&
+		git commit -m "add file2 to submodule"
+	) &&
+	(cd super &&
+		git submodule update
+	)
+'
+
+test_expect_success 'not moving submodule when the gitmodules config is not checked out' '
+	(cd super &&
+		test_must_fail git mv submodule moved_submodule
+	)
+'
+
+test_expect_success 'not removing submodule when the gitmodules config is not checked out' '
+	(cd super &&
+		test_must_fail git rm -r submodule
+	)
+'
+
+test_expect_success 'not adding submodules when the gitmodules config is not checked out' '
+	(cd super &&
+		test_must_fail git submodule add ../new_submodule
+	)
+'
+
+# "git add" in the test above fails as expected, however it still leaves the
+# cloned directory there and adds a config entry to .git/config. This is
+# because no cleanup is done by cmd_add in git-submodule.sh when "git
+# submodule--helper config" fails to add a new config setting.
+#
+# If we added the following commands to the test above:
+#
+#   rm -rf .git/modules/new_submodule &&
+#   git reset HEAD new_submodule &&
+#   rm -rf new_submodule
+#
+# then the repository would be in a clean status and the test below would
+# pass, but maybe cmd_add should do that.
+test_expect_failure 'init submodule after adding failed when the gitmodules config is not checked out' '
+	(cd super &&
+		git submodule init
+	)
+'
+
+test_done
-- 
2.17.0