[FFM-1355]: The golang SDK was not evaluating custom rules for segments added directly to the flag

What:
If a segment is added to the flag directly (as opposed to using the segmentMatch operator) then we
call segment.Evaluate()
This will check if the target is included, excluded or added via custom rules.

Why:
Previously we only checked in the target was included in a segment, it meant custom rules were being ignored.T

Author: Dave Johnston

evaluation/feature.go

@@ -85,10 +85,20 @@ type Clauses []Clause
 func (c Clauses) Evaluate(target *Target, segments Segments) bool {
 	// AND operation
 	for _, clause := range c {
-		// operator should be evaluated based on type of attribute
-		op, err := target.GetOperator(clause.Attribute)
-		if err != nil {
-			log.Warn(err)
+
+		// If this is a SegmentMatch clause, then we don't need to get the operator for the
+		// attribute, as it is handled inside the Evaluate code below.
+		//
+		// If it is any other type of clause (i.e. if its an equals, contains etc)
+		// then we need to get the appropriate operator depending on the type of attribute
+		var op types.ValueType
+		var err error
+
+		if clause.Op != segmentMatchOperator {
+			op, err = target.GetOperator(clause.Attribute)
+			if err != nil {
+				log.Warn(err)
+			}
 		}
 		if !clause.Evaluate(target, segments, op) {
 			return false
@@ -239,12 +249,8 @@ func (fc FeatureConfig) GetVariationName(target *Target) string {
 						if !ok {
 							log.Error("The segment in variation map is invalid")
 						} else {
-							if segment.Included != nil {
-								for _, t := range segment.Included {
-									if t == target.Identifier {
-										return variationMap.Variation
-									}
-								}
+							if segment.Evaluate(target) {
+								return variationMap.Variation
 							}
 						}
 					}