whitespace: symbolic links usually lack LF at the end

For a patch that touches a symbolic link, it is perfectly normal
that the contents ends with "\ No newline at end of file".  The
checks introduced recently to detect incomplete lines (i.e., a text
file that lack the newline on its final line) should not trigger.

Disable the check early for symbolic links, both in "git apply" and
"git diff" and test them.  For "git apply", we check only when the
postimage is a symbolic link regardless of the preimage, and we only
care about preimage when applying in reverse.  Similarly, "git diff"
would warn only when the postimage is a symbolic link, or the
preimage when running "git diff -R".

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index 3c8eb02e4f..b691d29479 100755
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -90,6 +90,32 @@ test_expect_success "new incomplete line in post-image" '
 	git -c core.whitespace=incomplete diff -R --check x
 '
 
+test_expect_success SYMLINKS "incomplete-line error is disabled for symlinks" '
+	test_when_finished "git reset --hard" &&
+	test_when_finished "rm -f mylink" &&
+
+	# a regular file with an incomplete line
+	printf "%s" one >mylink &&
+	git add mylink &&
+
+	# a symbolic link
+	rm mylink &&
+	ln -s two mylink &&
+
+	git -c diff.color=always -c core.whitespace=incomplete \
+		diff mylink >forward.raw &&
+	test_decode_color >forward <forward.raw &&
+	test_grep ! "<BRED>\\\\ No newline at end of file<RESET>" forward &&
+
+	git -c diff.color=always -c core.whitespace=incomplete \
+		diff -R mylink >reverse.raw &&
+	test_decode_color >reverse <reverse.raw &&
+	test_grep "<BRED>\\\\ No newline at end of file<RESET>" reverse &&
+
+	git -c core.whitespace=incomplete diff --check mylink &&
+	test_must_fail git -c core.whitespace=incomplete diff --check -R mylink
+'
+
 test_expect_success "Ray Lehtiniemi's example" '
 	cat <<-\EOF >x &&
 	do {