fix(golang): don't apply omitempty to nullable/union fields under --omit-empty

packages/quicktype-core/src/language/Golang/utils.ts

@@ -51,7 +51,8 @@ export function canOmitEmpty(
     omitEmptyOption: boolean,
 ): boolean {
     if (!cp.isOptional) return false;
-    if (omitEmptyOption) return true;
+    if (omitEmptyOption)
+        return !["union", "null", "any"].includes(cp.type.kind);
     const t = cp.type;
     return !["union", "null", "any"].includes(t.kind);
 }

test/inputs/json/priority/omit-empty.out.omit-empty.json

@@ -1,10 +1,12 @@
 {
     "results": [
         {
-            "age": 52
+            "age": 52,
+            "name": null
         },
         {
-            "age": 27
+            "age": 27,
+            "name": null
         }
     ]
 }

test/inputs/schema/nullable-optional-one-of.1.fail.enum.json

@@ -0,0 +1,4 @@
+{
+  "kind": "three",
+  "b": null
+}

test/inputs/schema/nullable-optional-one-of.1.json

@@ -0,0 +1,4 @@
+{
+  "kind": "one",
+  "b": null
+}

test/inputs/schema/nullable-optional-one-of.schema

@@ -0,0 +1,42 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "definitions": {
+    "bar": {
+      "type": ["string", "null"]
+    },
+    "one": {
+      "type": "object",
+      "properties": {
+        "kind": {
+          "type": "string",
+          "const": "one"
+        },
+        "b": {
+          "$ref": "#/definitions/bar"
+        }
+      },
+      "required": ["kind", "b"]
+    },
+    "two": {
+      "type": "object",
+      "properties": {
+        "kind": {
+          "type": "string",
+          "const": "two"
+        },
+        "b": {
+          "$ref": "#/definitions/bar"
+        }
+      },
+      "required": ["kind"]
+    }
+  },
+  "oneOf": [
+    {
+      "$ref": "#/definitions/one"
+    },
+    {
+      "$ref": "#/definitions/two"
+    }
+  ]
+}

test/languages.ts

@@ -25,6 +25,7 @@ const skipsEnumValueValidation = [
     "enum-large.schema",
     "optional-enum.schema",
     "const-non-string.schema",
+    "nullable-optional-one-of.schema",
     "all-of-additional-properties-false.schema",
 ];
 
@@ -551,9 +552,10 @@ export const GoLanguage: Language = {
     rendererOptions: {},
     quickTestRendererOptions: [
         // Runs against the expected-output file
-        // `omit-empty.out.omit-empty.json`, which asserts that `omitempty`
-        // actually drops the null field.
+        // `omit-empty.out.omit-empty.json`, which asserts that nullable
+        // fields preserve null instead of being omitted.
         ["omit-empty.json", { "omit-empty": "true" }],
+        ["nullable-optional-one-of.schema", { "omit-empty": "true" }],
     ],
     sourceFiles: ["src/language/Golang/index.ts"],
 };