teach config --blob option to parse config from database

This can be used to read configuration values directly from git's
database. For example it is useful for reading to be checked out
.gitmodules files directly from the database.

Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 70 insertions, 0 deletions

diff --git a/t/t1307-config-blob.sh b/t/t1307-config-blob.sh
new file mode 100755
index 0000000000..fdc257e66f
--- /dev/null
+++ b/t/t1307-config-blob.sh
@@ -0,0 +1,70 @@
+#!/bin/sh
+
+test_description='support for reading config from a blob'
+. ./test-lib.sh
+
+test_expect_success 'create config blob' '
+	cat >config <<-\EOF &&
+	[some]
+		value = 1
+	EOF
+	git add config &&
+	git commit -m foo
+'
+
+test_expect_success 'list config blob contents' '
+	echo some.value=1 >expect &&
+	git config --blob=HEAD:config --list >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'fetch value from blob' '
+	echo true >expect &&
+	git config --blob=HEAD:config --bool some.value >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'reading non-existing value from blob is an error' '
+	test_must_fail git config --blob=HEAD:config non.existing
+'
+
+test_expect_success 'reading from blob and file is an error' '
+	test_must_fail git config --blob=HEAD:config --system --list
+'
+
+test_expect_success 'reading from missing ref is an error' '
+	test_must_fail git config --blob=HEAD:doesnotexist --list
+'
+
+test_expect_success 'reading from non-blob is an error' '
+	test_must_fail git config --blob=HEAD --list
+'
+
+test_expect_success 'setting a value in a blob is an error' '
+	test_must_fail git config --blob=HEAD:config some.value foo
+'
+
+test_expect_success 'deleting a value in a blob is an error' '
+	test_must_fail git config --blob=HEAD:config --unset some.value
+'
+
+test_expect_success 'editing a blob is an error' '
+	test_must_fail git config --blob=HEAD:config --edit
+'
+
+test_expect_success 'parse errors in blobs are properly attributed' '
+	cat >config <<-\EOF &&
+	[some]
+		value = "
+	EOF
+	git add config &&
+	git commit -m broken &&
+
+	test_must_fail git config --blob=HEAD:config some.value 2>err &&
+
+	# just grep for our token as the exact error message is likely to
+	# change or be internationalized
+	grep "HEAD:config" err
+'
+
+test_done