tree: fix LIKE suboperator with NULL LHS

If a NULL value was present in the LHS of a suboperator with a LIKE
comparison, then previously the server would crash with a panic. Now it
is handled and there are tests.

closes cockroachdb#40841

Release note (bug fix): Fix a crash that occurs when a suboperator with
a LIKE comparison has a NULL left-hand side.

pkg/sql/sem/tree/eval.go

@@ -2330,6 +2330,9 @@ func MatchLikeEscape(
 }
 
 func matchLike(ctx *EvalContext, left, right Datum, caseInsensitive bool) (Datum, error) {
+	if left == DNull || right == DNull {
+		return DNull, nil
+	}
 	s, pattern := string(MustBeDString(left)), string(MustBeDString(right))
 	if len(s) == 0 {
 		// An empty string only matches with an empty pattern or a pattern

pkg/sql/sem/tree/testdata/eval/any_some_all

@@ -25,6 +25,21 @@ eval
 ----
 false
 
+eval
+'foo' LIKE ANY ARRAY[]
+----
+false
+
+eval
+'foo' LIKE ANY (ARRAY['bar', 'baz'])
+----
+false
+
+eval
+'foo' LIKE ANY (ARRAY['foo', 'bar', 'baz'])
+----
+true
+
 eval
 1+1 = SOME (ARRAY[1, 3, 4])
 ----
@@ -50,6 +65,21 @@ eval
 ----
 true
 
+eval
+'foo' LIKE ALL ARRAY[]
+----
+true
+
+eval
+'foo' LIKE ALL (ARRAY['foo', 'bar', 'baz'])
+----
+false
+
+eval
+'foo' LIKE ALL (ARRAY['foo', 'foo'])
+----
+true
+
 eval
 1 = ANY (ARRAY[1, 2, NULL])
 ----
@@ -87,6 +117,11 @@ eval
 ----
 NULL
 
+eval
+'foo' LIKE ANY(NULL::string[])
+----
+NULL
+
 eval
 NULL::int = ANY(NULL::int[])
 ----
@@ -102,6 +137,11 @@ NULL::int = ALL(NULL::int[])
 ----
 NULL
 
+eval
+NULL::string LIKE ANY(NULL::string[])
+----
+NULL
+
 # A null LHS has different behavior if the array is empty or not
 eval
 NULL::int = ANY(ARRAY[1,2])
@@ -133,6 +173,21 @@ NULL::int = ALL(ARRAY[]:::int[])
 ----
 true
 
+eval
+NULL::string LIKE ANY(ARRAY[]:::string[])
+----
+false
+
+eval
+NULL::string LIKE SOME(ARRAY[]:::string[])
+----
+false
+
+eval
+NULL::string LIKE ALL(ARRAY[]:::string[])
+----
+true
+
 eval
 1 = ALL (ARRAY[1, 2, NULL])
 ----
@@ -232,3 +287,19 @@ eval
 'aaa' NOT ILIKE ANY (ARRAY['%A%', '%A%'])
 ----
 false
+
+# Regression test for #40841 -- make sure LIKE can handle nulls.
+eval
+NULL::string LIKE ANY(ARRAY['bar', 'baz'])
+----
+NULL
+
+eval
+NULL::string ILIKE ANY(ARRAY['bar%', 'baz'])
+----
+NULL
+
+eval
+NULL::string LIKE ANY(ARRAY['bar', NULL])
+----
+NULL