From d8b76970b484365a618ed9095d3d13e64e0d3b64 Mon Sep 17 00:00:00 2001
From: SystemGlitch <jeremy.la@outlook.fr>
Date: Tue, 14 May 2024 10:22:43 +0200
Subject: [PATCH] Validation: fix reflect error on nil arrays

---
 util/walk/walk_test.go       | 50 +++++++++++++++++++++++++++++++++---
 validation/validator.go      |  3 +++
 validation/validator_test.go | 39 ++++++++++++++++++++++++++++
 3 files changed, 88 insertions(+), 4 deletions(-)

diff --git a/util/walk/walk_test.go b/util/walk/walk_test.go
index ed16b6fe..59095a03 100644
--- a/util/walk/walk_test.go
+++ b/util/walk/walk_test.go
@@ -256,7 +256,7 @@ func TestMustParse(t *testing.T) {
 	})
 }
 
-func testWalk(t *testing.T, data map[string]any, p string) []*Context {
+func testWalk(t *testing.T, data any, p string) []*Context {
 	matches := make([]*Context, 0, 5)
 	path, err := Parse(p)
 
@@ -877,7 +877,7 @@ func TestPathWalkWildcardEmptyObject(t *testing.T) {
 }
 
 func TestPathWalkEmptyArray(t *testing.T) {
-	data := map[string]any{
+	var data any = map[string]any{
 		"array":  []string{},
 		"narray": [][][]string{},
 	}
@@ -885,7 +885,7 @@ func TestPathWalkEmptyArray(t *testing.T) {
 	expected := []*Context{
 		{
 			Value:  nil,
-			Parent: data["array"],
+			Parent: data.(map[string]any)["array"],
 			Name:   "",
 			Path: &Path{
 				Name: strPtr("array"),
@@ -904,7 +904,7 @@ func TestPathWalkEmptyArray(t *testing.T) {
 	expected = []*Context{
 		{
 			Value:  nil,
-			Parent: data["narray"],
+			Parent: data.(map[string]any)["narray"],
 			Name:   "",
 			Path: &Path{
 				Name: strPtr("narray"),
@@ -916,6 +916,48 @@ func TestPathWalkEmptyArray(t *testing.T) {
 		},
 	}
 	assert.Equal(t, expected, matches)
+
+	// nil array
+	data = map[string]any{
+		"array": nil,
+	}
+	expected = []*Context{
+		{
+			Value:  nil,
+			Parent: data,
+			Name:   "array",
+			Path: &Path{
+				Name: strPtr("array"),
+				Type: PathTypeElement,
+				Next: nil,
+			},
+			Index: -1,
+			Found: ParentNotFound,
+		},
+	}
+
+	matches = testWalk(t, data, "array[]")
+	assert.Equal(t, expected, matches)
+
+	// array is the root element
+	data = []any{}
+	expected = []*Context{
+		{
+			Value:  nil,
+			Parent: data,
+			Name:   "",
+			Path: &Path{
+				Name: nil,
+				Type: PathTypeArray,
+				Next: &Path{},
+			},
+			Index: -1,
+			Found: ElementNotFound,
+		},
+	}
+
+	matches = testWalk(t, data, "[]")
+	assert.Equal(t, expected, matches)
 }
 
 func TestPathWalkNotFoundInObject(t *testing.T) {
diff --git a/validation/validator.go b/validation/validator.go
index 94c5f213..a2dcecd2 100644
--- a/validation/validator.go
+++ b/validation/validator.go
@@ -520,6 +520,9 @@ func makeGenericSlice(original any) ([]any, bool) {
 		return o, false
 	}
 	list := reflect.ValueOf(original)
+	if !list.IsValid() {
+		return []any{}, false
+	}
 	length := list.Len()
 	newSlice := make([]any, 0, length)
 	for i := 0; i < length; i++ {
diff --git a/validation/validator_test.go b/validation/validator_test.go
index 043d7d9e..80d507bb 100644
--- a/validation/validator_test.go
+++ b/validation/validator_test.go
@@ -716,6 +716,45 @@ func TestValidate(t *testing.T) {
 			},
 			wantData: map[string]any{"property": 123, "object": map[string]any{"property": 456}, "array": []int{7}, "narray": [][]int{{1, 8, 3}}},
 		},
+		{
+			desc: "empty_array",
+			options: &Options{
+				Data:     map[string]any{"narray": []any{}},
+				Language: lang.New().GetDefault(),
+				Rules: RuleSet{
+					{Path: "narray", Rules: List{Required(), Array()}},
+					{Path: "narray[]", Rules: List{Array()}},
+					{Path: "narray[][]", Rules: List{Int()}},
+				},
+			},
+			wantData: map[string]any{"narray": []any{}},
+		},
+		{
+			desc: "empty_narray",
+			options: &Options{
+				Data:     map[string]any{"narray": []any{[]any{}}},
+				Language: lang.New().GetDefault(),
+				Rules: RuleSet{
+					{Path: "narray", Rules: List{Required(), Array()}},
+					{Path: "narray[]", Rules: List{Array()}},
+					{Path: "narray[][]", Rules: List{Int()}},
+				},
+			},
+			wantData: map[string]any{"narray": [][]any{{}}},
+		},
+		{
+			desc: "nil_array",
+			options: &Options{
+				Data:     map[string]any{"narray": nil},
+				Language: lang.New().GetDefault(),
+				Rules: RuleSet{
+					{Path: "narray", Rules: List{Required(), Nullable(), Array()}},
+					{Path: "narray[]", Rules: List{Required(), Array()}},
+					{Path: "narray[][]", Rules: List{Int()}},
+				},
+			},
+			wantData: map[string]any{"narray": nil},
+		},
 		{
 			desc: "type-dependent",
 			options: &Options{