From a389bb64b8e6e2f37c029929c80b3cba3c352e74 Mon Sep 17 00:00:00 2001
From: Mike Farah <mikefarah@gmail.com>
Date: Fri, 31 Mar 2023 16:24:23 +1100
Subject: [PATCH] Fixed bug when splatting empty array #1613

---
 pkg/yqlib/operator_collect.go            | 5 +++++
 pkg/yqlib/operator_traverse_path.go      | 7 ++++++-
 pkg/yqlib/operator_traverse_path_test.go | 7 +++++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/pkg/yqlib/operator_collect.go b/pkg/yqlib/operator_collect.go
index a7f25465..2a114592 100644
--- a/pkg/yqlib/operator_collect.go
+++ b/pkg/yqlib/operator_collect.go
@@ -27,6 +27,7 @@ func collectOperator(d *dataTreeNavigator, context Context, expressionNode *Expr
 	log.Debugf("-- collectOperation")
 
 	if context.MatchingNodes.Len() == 0 {
+		log.Debugf("nothing to collect")
 		node := &yaml.Node{Kind: yaml.SequenceNode, Tag: "!!seq", Value: "[]"}
 		candidate := &CandidateNode{Node: node}
 		return context.SingleChildContext(candidate), nil
@@ -41,6 +42,7 @@ func collectOperator(d *dataTreeNavigator, context Context, expressionNode *Expr
 	}
 
 	if evaluateAllTogether {
+		log.Debugf("collect together")
 		collectedNode, err := collectTogether(d, context, expressionNode.RHS)
 		if err != nil {
 			return Context{}, err
@@ -56,6 +58,8 @@ func collectOperator(d *dataTreeNavigator, context Context, expressionNode *Expr
 		collectedNode := &yaml.Node{Kind: yaml.SequenceNode, Tag: "!!seq"}
 		collectCandidate := candidate.CreateReplacement(collectedNode)
 
+		log.Debugf("collect rhs: %v", expressionNode.RHS.Operation.toString())
+
 		collectExpResults, err := d.GetMatchingNodes(context.SingleChildContext(candidate), expressionNode.RHS)
 		if err != nil {
 			return Context{}, err
@@ -66,6 +70,7 @@ func collectOperator(d *dataTreeNavigator, context Context, expressionNode *Expr
 			log.Debugf("found this: %v", NodeToString(resultC))
 			collectedNode.Content = append(collectedNode.Content, unwrapDoc(resultC.Node))
 		}
+		log.Debugf("done collect rhs: %v", expressionNode.RHS.Operation.toString())
 
 		results.PushBack(collectCandidate)
 	}
diff --git a/pkg/yqlib/operator_traverse_path.go b/pkg/yqlib/operator_traverse_path.go
index 54e6baa7..4308545a 100644
--- a/pkg/yqlib/operator_traverse_path.go
+++ b/pkg/yqlib/operator_traverse_path.go
@@ -80,6 +80,8 @@ func traverseArrayOperator(d *dataTreeNavigator, context Context, expressionNode
 	// BUT we still return the original context back (see jq)
 	// https://stedolan.github.io/jq/manual/#Variable/SymbolicBindingOperator:...as$identifier|...
 
+	log.Debugf("--traverseArrayOperator")
+
 	if expressionNode.RHS != nil && expressionNode.RHS.RHS != nil && expressionNode.RHS.RHS.Operation.OperationType == createMapOpType {
 		return sliceArrayOperator(d, context, expressionNode.RHS.RHS)
 	}
@@ -103,6 +105,8 @@ func traverseArrayOperator(d *dataTreeNavigator, context Context, expressionNode
 	}
 	var indicesToTraverse = rhs.MatchingNodes.Front().Value.(*CandidateNode).Node.Content
 
+	log.Debugf("indicesToTraverse %v", len(indicesToTraverse))
+
 	//now we traverse the result of the lhs against the indices we found
 	result, err := traverseNodesWithArrayIndices(lhs, indicesToTraverse, prefs)
 	if err != nil {
@@ -231,7 +235,8 @@ func traverseMap(context Context, matchingNode *CandidateNode, keyNode *yaml.Nod
 		return nil, err
 	}
 
-	if !prefs.DontAutoCreate && !context.DontAutoCreate && newMatches.Len() == 0 {
+	if !splat && !prefs.DontAutoCreate && !context.DontAutoCreate && newMatches.Len() == 0 {
+		log.Debugf("no matches, creating one")
 		//no matches, create one automagically
 		valueNode := &yaml.Node{Tag: "!!null", Kind: yaml.ScalarNode, Value: "null"}
 
diff --git a/pkg/yqlib/operator_traverse_path_test.go b/pkg/yqlib/operator_traverse_path_test.go
index e82acc2b..5d62447c 100644
--- a/pkg/yqlib/operator_traverse_path_test.go
+++ b/pkg/yqlib/operator_traverse_path_test.go
@@ -35,6 +35,13 @@ steps:
 `
 
 var traversePathOperatorScenarios = []expressionScenario{
+	{
+		skipDoc:     true,
+		description: "splat empty map",
+		document:    "{}",
+		expression:  ".[]",
+		expected:    []string{},
+	},
 	{
 		skipDoc:    true,
 		document:   `[[1]]`,