t6038 (merge.renormalize): check that it can be turned off

An unusual sort of person (not me) may even enjoy the conflicts
from line-ending changes.  But more importantly, it is useful to
document that behavior so we can more easily notice if it changes
in an uncontrolled way while no one is watching.

Cc: Eyvind Bernhardsen <eyvind.bernhardsen@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t6038-merge-text-auto.sh

@@ -15,7 +15,6 @@ test_description='CRLF merge conflict across text=auto change
 . ./test-lib.sh
 
 test_expect_success setup '
-	git config merge.renormalize true &&
 	git config core.autocrlf false &&
 
 	echo first line | append_cr >file &&
@@ -59,12 +58,19 @@ test_expect_success setup '
 	git checkout master
 '
 
+test_expect_success 'set up fuzz_conflict() helper' '
+	fuzz_conflict() {
+		sed -e "s/^\([<>=]......\) .*/\1/" "$@"
+	}
+'
+
 test_expect_success 'Merge after setting text=auto' '
 	cat <<-\EOF >expected &&
 	first line
 	same line
 	EOF
 
+	git config merge.renormalize true &&
 	git rm -fr . &&
 	rm -f .gitattributes &&
 	git reset --hard a &&
@@ -78,6 +84,7 @@ test_expect_success 'Merge addition of text=auto' '
 	same line
 	EOF
 
+	git config merge.renormalize true &&
 	git rm -fr . &&
 	rm -f .gitattributes &&
 	git reset --hard b &&
@@ -85,12 +92,51 @@ test_expect_success 'Merge addition of text=auto' '
 	test_cmp expected file
 '
 
+test_expect_success 'Detect CRLF/LF conflict after setting text=auto' '
+	q_to_cr <<-\EOF >expected &&
+	<<<<<<<
+	first line
+	same line
+	=======
+	first lineQ
+	same lineQ
+	>>>>>>>
+	EOF
+
+	git config merge.renormalize false &&
+	rm -f .gitattributes &&
+	git reset --hard a &&
+	test_must_fail git merge b &&
+	fuzz_conflict file >file.fuzzy &&
+	test_cmp expected file.fuzzy
+'
+
+test_expect_success 'Detect LF/CRLF conflict from addition of text=auto' '
+	q_to_cr <<-\EOF >expected &&
+	<<<<<<<
+	first lineQ
+	same lineQ
+	=======
+	first line
+	same line
+	>>>>>>>
+	EOF
+
+	git config merge.renormalize false &&
+	rm -f .gitattributes &&
+	git reset --hard b &&
+	test_must_fail git merge a &&
+	fuzz_conflict file >file.fuzzy &&
+	test_cmp expected file.fuzzy
+'
+
 test_expect_failure 'checkout -m after setting text=auto' '
 	cat <<-\EOF >expected &&
 	first line
 	same line
 	EOF
 
+	git config merge.renormalize true &&
 	git rm -fr . &&
 	rm -f .gitattributes &&
 	git reset --hard initial &&
@@ -105,6 +151,7 @@ test_expect_failure 'checkout -m addition of text=auto' '
 	same line
 	EOF
 
+	git config merge.renormalize true &&
 	git rm -fr . &&
 	rm -f .gitattributes file &&
 	git reset --hard initial &&
@@ -119,6 +166,7 @@ test_expect_failure 'cherry-pick patch from after text=auto was added' '
 	same line
 	EOF
 
+	git config merge.renormalize true &&
 	git rm -fr . &&
 	git reset --hard b &&
 	test_must_fail git cherry-pick a >err 2>&1 &&