fix: additional coverage, redundant api decorator error

Author: jhefferman-sfdc

packages/@lwc/engine-server/src/__tests__/fixtures/api/setter/error.txt

@@ -1,7 +1,7 @@
 import { LightningElement } from 'lwc';
 
-const privateFields = undefined;
-const api = undefined;
+const privateProperties = undefined;
+const publicProperties = undefined;
 const stylesheetScopeToken = undefined;
 const hasScopedStylesheets = undefined;
 const defaultScopedStylesheets = undefined;
@@ -12,8 +12,8 @@ export default class extends LightningElement {
         Object.assign(
             {},
             {
-                privateFields,
-                api,
+                privateProperties,
+                publicProperties,
                 stylesheetScopeToken,
                 hasScopedStylesheets,
                 defaultScopedStylesheets,

packages/@lwc/engine-server/src/__tests__/fixtures/api/setter/expected.html

@@ -16,8 +16,8 @@ import type { ComponentMetaState } from './types';
 
 const bGenerateMarkup = esTemplate`
     // These variables may mix with component-authored variables, so should be reasonably unique
-    const __lwcApi__ = new Set(${/*api*/ is.arrayExpression});
-    const __lwcPrivateFields__ = new Set(${/*private fields*/ is.arrayExpression});
+    const __lwcPublicProperties__ = new Set(${/*api*/ is.arrayExpression});
+    const __lwcPrivateProperties__ = new Set(${/*private fields*/ is.arrayExpression});
 
     async function* generateMarkup(
             tagName, 
@@ -43,8 +43,8 @@ const bGenerateMarkup = esTemplate`
         instance[__SYMBOL__SET_INTERNALS](
             props,
             attrs,
-            __lwcApi__,
-            __lwcPrivateFields__,
+            __lwcPublicProperties__,
+            __lwcPrivateProperties__,
         );
         instance.isConnected = true;
         if (instance.connectedCallback) {
@@ -101,7 +101,7 @@ export function addGenerateMarkupFunction(
     tagName: string,
     filename: string
 ) {
-    const { privateFields, api, tmplExplicitImports } = state;
+    const { privateProperties, publicProperties, tmplExplicitImports } = state;
 
     // The default tag name represents the component name that's passed to the transformer.
     // This is needed to generate markup for dynamic components which are invoked through
@@ -141,8 +141,8 @@ export function addGenerateMarkupFunction(
     );
     program.body.push(
         ...bGenerateMarkup(
-            b.arrayExpression(api.map(b.literal)),
-            b.arrayExpression(privateFields.map(b.literal)),
+            b.arrayExpression(publicProperties.map(b.literal)),
+            b.arrayExpression(privateProperties.map(b.literal)),
             defaultTagName,
             classIdentifier,
             connectWireAdapterCode

packages/@lwc/engine-server/src/__tests__/fixtures/api/setter/index.js

@@ -101,16 +101,16 @@ const visitors: Visitors = {
         validateUniqueDecorator(decorators);
         const decoratedExpression = decorators?.[0]?.expression;
         if (is.identifier(decoratedExpression) && decoratedExpression.name === 'api') {
-            state.api.push(node.key.name);
+            state.publicProperties.push(node.key.name);
         } else if (
             is.callExpression(decoratedExpression) &&
             is.identifier(decoratedExpression.callee) &&
             decoratedExpression.callee.name === 'wire'
         ) {
             catalogWireAdapters(path, state);
-            state.privateFields.push(node.key.name);
+            state.privateProperties.push(node.key.name);
         } else {
-            state.privateFields.push(node.key.name);
+            state.privateProperties.push(node.key.name);
         }
 
         if (
@@ -165,7 +165,12 @@ const visitors: Visitors = {
                 catalogWireAdapters(path, state);
             }
         } else if (is.identifier(decoratedExpression) && decoratedExpression.name === 'api') {
-            state.api.push(node.key.name);
+            if (state.publicProperties.includes(node.key.name)) {
+                throw new Error(
+                    `LWC1112: @api get ${node.key.name} and @api set ${node.key.name} detected in class declaration. Only one of the two needs to be decorated with @api.`
+                );
+            }
+            state.publicProperties.push(node.key.name);
         }
 
         switch (node.key.name) {
@@ -271,8 +276,8 @@ export default function compileJS(
         tmplExplicitImports: null,
         cssExplicitImports: null,
         staticStylesheetIds: null,
-        api: [],
-        privateFields: [],
+        publicProperties: [],
+        privateProperties: [],
         wireAdapters: [],
         experimentalDynamicComponent: options.experimentalDynamicComponent,
         importManager: new ImportManager(),