Fixing merge anchor key order

pkg/yqlib/operator_anchors_aliases.go

@@ -138,6 +138,41 @@ func explodeOperator(d *dataTreeNavigator, context Context, expressionNode *Expr
 	return context, nil
 }
 
+func fixedReconstructAliasedMap(node *CandidateNode) error {
+	var newContent = []*CandidateNode{}
+
+	for index := 0; index < len(node.Content); index = index + 2 {
+		keyNode := node.Content[index]
+		valueNode := node.Content[index+1]
+		if keyNode.Value != "<<" {
+			// always add in plain nodes
+			newContent = append(newContent, keyNode, valueNode)
+		} else {
+			sequence := valueNode
+			if sequence.Kind != SequenceNode {
+				sequence = &CandidateNode{Content: []*CandidateNode{sequence}}
+			}
+			for index := 0; index < len(sequence.Content); index = index + 1 {
+				// for merge anchors, we only set them if the key is not already in node or the newContent
+				mergeNodeSeq := sequence.Content[index]
+				if mergeNodeSeq.Kind == AliasNode {
+					mergeNodeSeq = mergeNodeSeq.Alias
+				}
+				if mergeNodeSeq.Kind != MappingNode {
+					return fmt.Errorf("merge anchor only supports maps, got !!seq instead")
+				}
+				itemsToAdd := mergeNodeSeq.FilterMapContentByKey(func(keyNode *CandidateNode) bool {
+					return getContentValueByKey(node.Content, keyNode.Value) == nil &&
+						getContentValueByKey(newContent, keyNode.Value) == nil
+				})
+				newContent = append(newContent, itemsToAdd...)
+			}
+		}
+	}
+	node.Content = newContent
+	return nil
+}
+
 func reconstructAliasedMap(node *CandidateNode, context Context) error {
 	var newContent = list.New()
 	// can I short cut here by prechecking if there's an anchor in the map?
@@ -215,6 +250,10 @@ func explodeNode(node *CandidateNode, context Context) error {
 		}
 
 		if hasAlias {
+			if ConfiguredYamlPreferences.FixMergeAnchorToSpec {
+				return fixedReconstructAliasedMap(node)
+			}
+			log.Warning("--yaml-fix-merge-anchor-to-spec is false; causing merge anchors to override the existing values which isn't to the yaml spec. This flag will default to true in late 2025.")
 			// this is a slow op, which is why we want to check before running it.
 			return reconstructAliasedMap(node, context)
 		}
@@ -272,10 +311,7 @@ func overrideEntry(node *CandidateNode, key *CandidateNode, value *CandidateNode
 		log.Debugf("checking new content %v:%v", keyNode.Value, valueEl.Value.(*CandidateNode).Value)
 		if keyNode.Value == key.Value && keyNode.Alias == nil && key.Alias == nil {
 			log.Debugf("overridign new content")
-			if !ConfiguredYamlPreferences.FixMergeAnchorToSpec {
-				log.Warning("--yaml-fix-merge-anchor-to-spec is false; causing the merge anchor to override the existing value at %v which isn't to the yaml spec. This flag will default to true in late 2025.", keyNode.GetNicePath())
-				valueEl.Value = value
-			}
+			valueEl.Value = value
 			return nil
 		}
 		newEl = valueEl // move forward twice