From c8f4ba7f45e3f043a65eb0290fc970ddc35cab08 Mon Sep 17 00:00:00 2001
From: Mike Farah <mikefarah@gmail.com>
Date: Wed, 18 Oct 2023 12:36:52 +1100
Subject: [PATCH] Removing copier lib

---
 pkg/yqlib/context.go      | 40 ++++++++++++------------------
 pkg/yqlib/context_test.go | 51 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 24 deletions(-)
 create mode 100644 pkg/yqlib/context_test.go

diff --git a/pkg/yqlib/context.go b/pkg/yqlib/context.go
index d2dc656b..aaa80da6 100644
--- a/pkg/yqlib/context.go
+++ b/pkg/yqlib/context.go
@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"time"
 
-	"github.com/jinzhu/copier"
 	logging "gopkg.in/op/go-logging.v1"
 )
 
@@ -58,13 +57,19 @@ func (n *Context) SetVariable(name string, value *list.List) {
 func (n *Context) ChildContext(results *list.List) Context {
 	clone := Context{DontAutoCreate: n.DontAutoCreate, datetimeLayout: n.datetimeLayout}
 	clone.Variables = make(map[string]*list.List)
-	if len(n.Variables) > 0 {
-		err := copier.Copy(&clone.Variables, n.Variables)
-		if err != nil {
-			log.Error("Error cloning context :(")
-			panic(err)
+	for variableKey, originalValueList := range n.Variables {
+
+		variableCopyList := list.New()
+		for el := originalValueList.Front(); el != nil; el = el.Next() {
+			// note that we dont make a copy of the candidate node
+			// this is so the 'ref' operator can work correctly.
+			clonedNode := el.Value.(*CandidateNode)
+			variableCopyList.PushBack(clonedNode)
 		}
+
+		clone.Variables[variableKey] = variableCopyList
 	}
+
 	clone.MatchingNodes = results
 	return clone
 }
@@ -78,31 +83,18 @@ func (n *Context) ToString() string {
 }
 
 func (n *Context) DeepClone() Context {
-	clone := Context{}
-	err := copier.Copy(&clone, n)
-	// copier doesn't do lists properly for some reason
-	clone.MatchingNodes = list.New()
+
+	clonedContent := list.New()
 	for el := n.MatchingNodes.Front(); el != nil; el = el.Next() {
 		clonedNode := el.Value.(*CandidateNode).Copy()
-		clone.MatchingNodes.PushBack(clonedNode)
+		clonedContent.PushBack(clonedNode)
 	}
 
-	if err != nil {
-		log.Error("Error cloning context :(")
-		panic(err)
-	}
-	return clone
+	return n.ChildContext(clonedContent)
 }
 
 func (n *Context) Clone() Context {
-	clone := Context{}
-	err := copier.Copy(&clone, n)
-
-	if err != nil {
-		log.Error("Error cloning context :(")
-		panic(err)
-	}
-	return clone
+	return n.ChildContext(n.MatchingNodes)
 }
 
 func (n *Context) ReadOnlyClone() Context {
diff --git a/pkg/yqlib/context_test.go b/pkg/yqlib/context_test.go
new file mode 100644
index 00000000..13ec0e2f
--- /dev/null
+++ b/pkg/yqlib/context_test.go
@@ -0,0 +1,51 @@
+package yqlib
+
+import (
+	"container/list"
+	"testing"
+
+	"github.com/mikefarah/yq/v4/test"
+)
+
+func TestChildContext(t *testing.T) {
+
+	expectedOriginal := make(map[string]*list.List)
+	expectedOriginal["dog"] = list.New()
+	expectedOriginal["dog"].PushBack(&CandidateNode{Value: "woof"})
+
+	originalVariables := make(map[string]*list.List)
+	originalVariables["dog"] = list.New()
+	originalVariables["dog"].PushBack(&CandidateNode{Value: "woof"})
+
+	original := Context{
+		DontAutoCreate: true,
+		datetimeLayout: "cat",
+		Variables:      originalVariables,
+	}
+
+	newResults := list.New()
+	newResults.PushBack(&CandidateNode{Value: "bar"})
+
+	clone := original.ChildContext(newResults)
+	test.AssertResultComplex(t, originalVariables, clone.Variables)
+
+	clone.Variables["dog"].PushBack("bark")
+	// ensure this is a separate copy
+	test.AssertResultComplex(t, 1, originalVariables["dog"].Len())
+
+}
+
+func TestChildContextNoVariables(t *testing.T) {
+
+	original := Context{
+		DontAutoCreate: true,
+		datetimeLayout: "cat",
+	}
+
+	newResults := list.New()
+	newResults.PushBack(&CandidateNode{Value: "bar"})
+
+	clone := original.ChildContext(newResults)
+	test.AssertResultComplex(t, make(map[string]*list.List), clone.Variables)
+
+}