Removes nil check for required properties

Author: Henkoglobin

pkg/generator/validator.go

@@ -35,7 +35,10 @@ type requiredValidator struct {
 }
 
 func (v *requiredValidator) generate(out *codegen.Emitter) {
-	out.Printlnf(`if v, ok := %s["%s"]; !ok || v == nil {`, varNameRawMap, v.jsonName)
+	// The container itself may be null (if the type is ["null", "object"]), in which case
+	// the map will be nil and none of the properties are present. This shouldn't fail
+	// the validation, though, as that's allowed as long as the container is allowed to be null.
+	out.Printlnf(`if _, ok := %s["%s"]; %s != nil && !ok {`, varNameRawMap, v.jsonName, varNameRawMap)
 	out.Indent(1)
 	out.Printlnf(`return fmt.Errorf("field %s in %s: required")`, v.jsonName, v.declName)
 	out.Indent(-1)

tests/data/core/date/date.go

@@ -0,0 +1,41 @@
+{
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "id": "https://example.com/requiredNullable",
+  "type": "object",
+  "properties": {
+    "myNullableString": {
+      "type": [
+        "string",
+        "null"
+      ]
+    },
+    "myNullableStringArray": {
+      "type": [
+        "array",
+        "null"
+      ],
+      "items": {
+        "type": "string"
+      }
+    },
+    "myNullableObject": {
+      "type": [
+        "object",
+        "null"
+      ],
+      "properties": {
+        "myNestedProp": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "myNestedProp"
+      ]
+    }
+  },
+  "required": [
+    "myNullableString",
+    "myNullableStringArray",
+    "myNullableObject"
+  ]
+}

tests/data/core/dateTime/dateTime.go

@@ -7,6 +7,7 @@ import (
 
 	testMaxLength "github.com/atombender/go-jsonschema/tests/data/validation/maxLength"
 	testMinLength "github.com/atombender/go-jsonschema/tests/data/validation/minLength"
+	testRequiredFields "github.com/atombender/go-jsonschema/tests/data/validation/requiredFields"
 	"github.com/atombender/go-jsonschema/tests/helpers"
 )
 
@@ -112,3 +113,42 @@ func TestMinStringLength(t *testing.T) {
 		})
 	}
 }
+
+func TestRequiredFields(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		desc    string
+		data    string
+		wantErr error
+	}{
+		{
+			desc:    "object without required property fails validation",
+			data:    `{}`,
+			wantErr: errors.New("field myNullableObject in RequiredNullable: required"),
+		},
+		{
+			desc:    "required properties may be null",
+			data:    `{ "myNullableObject": null, "myNullableStringArray": null, "myNullableString": null }`,
+			wantErr: nil,
+		},
+		{
+			desc:    "required properties may have a non-null value",
+			data:    `{ "myNullableObject": { "myNestedProp": "世界" }, "myNullableStringArray": ["hello"], "myNullableString": "world" }`,
+			wantErr: nil,
+		},
+	}
+	for _, tC := range testCases {
+		tC := tC
+
+		t.Run(tC.desc, func(t *testing.T) {
+			t.Parallel()
+
+			model := testRequiredFields.RequiredNullable{}
+
+			err := json.Unmarshal([]byte(tC.data), &model)
+
+			helpers.CheckError(t, tC.wantErr, err)
+		})
+	}
+}