fix(storage): fixes panic when building predicates

Fixes #15916.

If a predicate was passed in with multiple key/value matches for the
same tag key, then the value index would be incorrect. This ensures that
each tag key can only be added to the location map once.

tsdb/tsm1/predicate.go

@@ -75,9 +75,17 @@ func NewProtobufPredicate(pred *datatypes.Predicate) (Predicate, error) {
 		if node.GetNodeType() == datatypes.NodeTypeTagRef {
 			switch value := node.GetValue().(type) {
 			case *datatypes.Node_TagRefValue:
+				// Only add to the matcher locations the first time we encounter
+				// the tag key reference. This prevents problems with redundant
+				// predicates like:
+				//
+				//   foo = a AND foo = b
+				//   foo = c AND foo = d
+				if _, ok := locs[value.TagRefValue]; !ok {
 					locs[value.TagRefValue] = len(locs)
 				}
 			}
+		}
 	})
 
 	// Construct the shared state and root predicate node.

tsdb/tsm1/predicate_test.go

@@ -85,6 +85,16 @@ func TestPredicate_Matches(t *testing.T) {
 			Matches: true,
 		},
 
+		{
+			Name: "Logical And Matching Reduce (Simplify)",
+			Predicate: predicate(
+				andNode(
+					comparisonNode(datatypes.ComparisonEqual, tagNode("foo"), stringNode("bar")),
+					comparisonNode(datatypes.ComparisonNotEqual, tagNode("foo"), stringNode("bif")))),
+			Key:     "bucketorg,baz=bif,foo=bar,tag3=val3",
+			Matches: true,
+		},
+
 		{
 			Name: "Regex Matching",
 			Predicate: predicate(