fix: add validation for function names to start with capital letter

packages/decorators/src/plugin/function.ts

@@ -3,6 +3,10 @@ import { FunctionOptions } from './types';
 
 export function Function(name: string, options: FunctionOptions = {}) {
   return function (cls: any, methodName: string | null) {
+    // Validate that function name starts with a capital letter
+    if (!/^[A-Z]/.test(name)) {
+      throw new Error(`Function: function name '${name}' must start with a capital letter`);
+    }
     const sync = options && !!options.sync;
     const isMethod = typeof methodName === 'string';
     const f = isMethod ? cls[methodName] : cls;

packages/neovim/src/host/NvimPlugin.test.ts

@@ -68,6 +68,12 @@ describe('NvimPlugin', () => {
     expect(plugin.functions.MyFunction).toEqual({ fn, spec });
   });
 
+  it('should not register functions with lowercase names', () => {
+    const plugin = new NvimPlugin('/tmp/filename', () => {}, getFakeNvimClient());
+    plugin.registerFunction('myLowercaseFunction', () => {}, {});
+    expect(Object.keys(plugin.functions)).toHaveLength(0);
+  });
+
   it('should not add autocmds with no pattern option', () => {
     const plugin = new NvimPlugin('/tmp/filename', () => {}, getFakeNvimClient());
     plugin.registerAutocmd('BufWritePre', () => {}, { pattern: '' });

packages/neovim/src/host/NvimPlugin.ts

@@ -165,6 +165,13 @@ export class NvimPlugin {
   registerFunction(name: string, fn: [any, Function], options?: NvimFunctionOptions): void;
 
   registerFunction(name: string, fn: any, options?: NvimFunctionOptions): void {
+    if (!/^[A-Z]/.test(name)) {
+      this.nvim.logger.error(
+        `registerFunction: function name '${name}' must start with a capital letter`
+      );
+      return;
+    }
+
     const spec: Spec = {
       type: 'function',
       name,

packages/neovim/src/plugin/function.ts

@@ -13,6 +13,10 @@ export function nvimFunction(name: string, options: NvimFunctionOptions = {}) {
     // sync,
     // ...opts,
     // } = options;
+    // Validate that function name starts with a capital letter
+    if (!/^[A-Z]/.test(name)) {
+      throw new Error(`nvimFunction: function name '${name}' must start with a capital letter`);
+    }
     const sync = options && !!options.sync;
     const isMethod = typeof methodName === 'string';
     const f = isMethod ? cls[methodName] : cls;