grep: Fix -f FILE when FILE is empty and -x provided

Grep currently special-cased empty pattern file to be the same as
pattern file with one empty line (empty pattern). That does mirror how
GNU grep behaves, except when -x is provided. In that case .* pattern
needs to be used instead.

Signed-off-by: Gray Wolf <wolf@wolfsden.cz>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/testsuite/grep.tests b/testsuite/grep.tests
index 26f8e69cf..9c1f35499 100755
--- a/testsuite/grep.tests
+++ b/testsuite/grep.tests
@@ -129,6 +129,12 @@ testing "grep -v -f EMPTY_FILE" \
         "" \
         "test\n"
 
+testing "grep -vxf EMPTY_FILE" \
+        "grep -vxf input" \
+        "test\n" \
+        "" \
+        "test\n"
+
 testing "grep -Fw matches only words" \
         "grep -Fw foo input" \
         "" \