fix: throw error when accessing private method without a getter (#12689)

* fix: class private accessor without getter

* Provide default return if 'writeOnlyError' is not available

* Add warning for old `@babel/helpers`

* Add missing helper call

packages/babel-helper-create-class-features-plugin/src/fields.js

@@ -225,6 +225,16 @@ const privateNameHandlerSpec = {
 
     if (isMethod) {
       if (isAccessor) {
+        if (!getId && setId) {
+          if (file.availableHelper("writeOnlyError")) {
+            return t.callExpression(file.addHelper("writeOnlyError"), [
+              t.stringLiteral(name),
+            ]);
+          }
+          console.warn(
+            `@babel/helpers is outdated, update it to silence this warning.`,
+          );
+        }
         return t.callExpression(file.addHelper("classPrivateFieldGet"), [
           this.receiver(member),
           t.cloneNode(id),

packages/babel-helpers/src/helpers.js

@@ -875,6 +875,12 @@ helpers.readOnlyError = helper("7.0.0-beta.0")`
   }
 `;
 
+helpers.writeOnlyError = helper("7.12.12")`
+  export default function _writeOnlyError(name) {
+    throw new TypeError("\\"" + name + "\\" is write-only");
+  }
+`;
+
 helpers.classNameTDZError = helper("7.0.0-beta.0")`
   export default function _classNameTDZError(name) {
     throw new Error("Class \\"" + name + "\\" cannot be referenced in computed property keys.");

packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/get-only-setter/exec.js

@@ -6,7 +6,7 @@ class Cl {
   }
 
   constructor() {
-    expect(this.#privateFieldValue).toBeUndefined();
+    expect(() => this.#privateFieldValue).toThrow(TypeError);
   }
 }
 

packages/babel-plugin-proposal-private-methods/test/fixtures/accessors/get-only-setter/output.js

@@ -14,7 +14,7 @@ class Cl {
       value: 0
     });
 
-    this.publicField = babelHelpers.classPrivateFieldGet(this, _privateFieldValue);
+    this.publicField = babelHelpers.writeOnlyError("privateFieldValue");
   }
 
 }

packages/babel-runtime-corejs2/package.json

@@ -60,6 +60,7 @@
     "./helpers/taggedTemplateLiteral": "./helpers/taggedTemplateLiteral.js",
     "./helpers/taggedTemplateLiteralLoose": "./helpers/taggedTemplateLiteralLoose.js",
     "./helpers/readOnlyError": "./helpers/readOnlyError.js",
+    "./helpers/writeOnlyError": "./helpers/writeOnlyError.js",
     "./helpers/classNameTDZError": "./helpers/classNameTDZError.js",
     "./helpers/temporalUndefined": "./helpers/temporalUndefined.js",
     "./helpers/tdz": "./helpers/tdz.js",
@@ -140,6 +141,7 @@
     "./helpers/esm/taggedTemplateLiteral": "./helpers/esm/taggedTemplateLiteral.js",
     "./helpers/esm/taggedTemplateLiteralLoose": "./helpers/esm/taggedTemplateLiteralLoose.js",
     "./helpers/esm/readOnlyError": "./helpers/esm/readOnlyError.js",
+    "./helpers/esm/writeOnlyError": "./helpers/esm/writeOnlyError.js",
     "./helpers/esm/classNameTDZError": "./helpers/esm/classNameTDZError.js",
     "./helpers/esm/temporalUndefined": "./helpers/esm/temporalUndefined.js",
     "./helpers/esm/tdz": "./helpers/esm/tdz.js",

packages/babel-runtime-corejs3/package.json

@@ -59,6 +59,7 @@
     "./helpers/taggedTemplateLiteral": "./helpers/taggedTemplateLiteral.js",
     "./helpers/taggedTemplateLiteralLoose": "./helpers/taggedTemplateLiteralLoose.js",
     "./helpers/readOnlyError": "./helpers/readOnlyError.js",
+    "./helpers/writeOnlyError": "./helpers/writeOnlyError.js",
     "./helpers/classNameTDZError": "./helpers/classNameTDZError.js",
     "./helpers/temporalUndefined": "./helpers/temporalUndefined.js",
     "./helpers/tdz": "./helpers/tdz.js",
@@ -139,6 +140,7 @@
     "./helpers/esm/taggedTemplateLiteral": "./helpers/esm/taggedTemplateLiteral.js",
     "./helpers/esm/taggedTemplateLiteralLoose": "./helpers/esm/taggedTemplateLiteralLoose.js",
     "./helpers/esm/readOnlyError": "./helpers/esm/readOnlyError.js",
+    "./helpers/esm/writeOnlyError": "./helpers/esm/writeOnlyError.js",
     "./helpers/esm/classNameTDZError": "./helpers/esm/classNameTDZError.js",
     "./helpers/esm/temporalUndefined": "./helpers/esm/temporalUndefined.js",
     "./helpers/esm/tdz": "./helpers/esm/tdz.js",

packages/babel-runtime/package.json

@@ -59,6 +59,7 @@
     "./helpers/taggedTemplateLiteral": "./helpers/taggedTemplateLiteral.js",
     "./helpers/taggedTemplateLiteralLoose": "./helpers/taggedTemplateLiteralLoose.js",
     "./helpers/readOnlyError": "./helpers/readOnlyError.js",
+    "./helpers/writeOnlyError": "./helpers/writeOnlyError.js",
     "./helpers/classNameTDZError": "./helpers/classNameTDZError.js",
     "./helpers/temporalUndefined": "./helpers/temporalUndefined.js",
     "./helpers/tdz": "./helpers/tdz.js",
@@ -139,6 +140,7 @@
     "./helpers/esm/taggedTemplateLiteral": "./helpers/esm/taggedTemplateLiteral.js",
     "./helpers/esm/taggedTemplateLiteralLoose": "./helpers/esm/taggedTemplateLiteralLoose.js",
     "./helpers/esm/readOnlyError": "./helpers/esm/readOnlyError.js",
+    "./helpers/esm/writeOnlyError": "./helpers/esm/writeOnlyError.js",
     "./helpers/esm/classNameTDZError": "./helpers/esm/classNameTDZError.js",
     "./helpers/esm/temporalUndefined": "./helpers/esm/temporalUndefined.js",
     "./helpers/esm/tdz": "./helpers/esm/tdz.js",