From 4d88d51b1b5d7d3e9513ac424fac5ef870f47e81 Mon Sep 17 00:00:00 2001
From: Steven WdV <swdv@cs.ru.nl>
Date: Mon, 16 Jun 2025 13:36:42 +0200
Subject: [PATCH] Fix precedence of merge anchor sequence for traverse (explode
 was already correct)

---
 pkg/yqlib/doc/operators/traverse-read.md |  8 ++++----
 pkg/yqlib/operator_traverse_path.go      | 14 ++++++++------
 pkg/yqlib/operator_traverse_path_test.go |  8 ++++----
 3 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/pkg/yqlib/doc/operators/traverse-read.md b/pkg/yqlib/doc/operators/traverse-read.md
index fefe24df..af5c965b 100644
--- a/pkg/yqlib/doc/operators/traverse-read.md
+++ b/pkg/yqlib/doc/operators/traverse-read.md
@@ -399,7 +399,7 @@ foobar_thing
 ```
 
 ## Traversing merge anchor lists
-Note that the later merge anchors override previous
+Note that the keys earlier in the merge anchors sequence override later ones
 
 Given a sample.yml file of:
 ```yaml
@@ -428,7 +428,7 @@ yq '.foobarList.thing' sample.yml
 ```
 will output
 ```yaml
-bar_thing
+foo_thing
 ```
 
 ## Splatting merge anchor lists
@@ -460,9 +460,9 @@ yq '.foobarList[]' sample.yml
 will output
 ```yaml
 bar_b
-foo_a
-bar_thing
+foo_thing
 foobarList_c
+foo_a
 ```
 
 ## Select multiple indices
diff --git a/pkg/yqlib/operator_traverse_path.go b/pkg/yqlib/operator_traverse_path.go
index 88c8f31d..ecdeafbd 100644
--- a/pkg/yqlib/operator_traverse_path.go
+++ b/pkg/yqlib/operator_traverse_path.go
@@ -292,15 +292,17 @@ func doTraverseMap(newMatches *orderedmap.OrderedMap, node *CandidateNode, wante
 	return nil
 }
 
-func traverseMergeAnchor(newMatches *orderedmap.OrderedMap, value *CandidateNode, wantedKey string, prefs traversePreferences, splat bool) error {
-	if value.Kind == AliasNode {
-		value = value.Alias
+func traverseMergeAnchor(newMatches *orderedmap.OrderedMap, merge *CandidateNode, wantedKey string, prefs traversePreferences, splat bool) error {
+	if merge.Kind == AliasNode {
+		merge = merge.Alias
 	}
-	switch value.Kind {
+	switch merge.Kind {
 	case MappingNode:
-		return doTraverseMap(newMatches, value, wantedKey, prefs, splat)
+		return doTraverseMap(newMatches, merge, wantedKey, prefs, splat)
 	case SequenceNode:
-		for _, childValue := range value.Content {
+		// Earlier keys take precedence
+		for index := len(merge.Content) - 1; index >= 0; index = index - 1 {
+			childValue := merge.Content[index]
 			if childValue.Kind == AliasNode {
 				childValue = childValue.Alias
 			}
diff --git a/pkg/yqlib/operator_traverse_path_test.go b/pkg/yqlib/operator_traverse_path_test.go
index bf1cad19..4b456d0e 100644
--- a/pkg/yqlib/operator_traverse_path_test.go
+++ b/pkg/yqlib/operator_traverse_path_test.go
@@ -449,11 +449,11 @@ var traversePathOperatorScenarios = []expressionScenario{
 	},
 	{
 		description:    "Traversing merge anchor lists",
-		subdescription: "Note that the later merge anchors override previous",
+		subdescription: "Note that the keys earlier in the merge anchors sequence override later ones",
 		document:       mergeDocSample,
 		expression:     `.foobarList.thing`,
 		expected: []string{
-			"D0, P[bar thing], (!!str)::bar_thing\n",
+			"D0, P[foo thing], (!!str)::foo_thing\n",
 		},
 	},
 	{
@@ -478,9 +478,9 @@ var traversePathOperatorScenarios = []expressionScenario{
 		expression:  `.foobarList[]`,
 		expected: []string{
 			"D0, P[bar b], (!!str)::bar_b\n",
-			"D0, P[foo a], (!!str)::foo_a\n",
-			"D0, P[bar thing], (!!str)::bar_thing\n",
+			"D0, P[foo thing], (!!str)::foo_thing\n",
 			"D0, P[foobarList c], (!!str)::foobarList_c\n",
+			"D0, P[foo a], (!!str)::foo_a\n",
 		},
 	},
 	{