fix: return the exe name if the file doesn't exist

Author: aminya

README.md

@@ -85,7 +85,7 @@ Note that you will also need to add various entries to the `providedServices` an
 
 ### Minimal example (General LSP exe)
 
-If the LSP is a general executable (not a JavaScript file), you should use `spawn` inside `startServerProcess`. `getExePath` is a cross-platform utility function to get the exe path for the given exe name (under the `bin/platform-arch/exeName` by default).
+If the LSP is a general executable (not a JavaScript file), you should use `spawn` inside `startServerProcess`. `getExePath` is a cross-platform utility function to get the exe path for the given exe name (under the `bin/platform-arch/exeName` by default or `exeName` if the file doesn't exist).
 
 ```javascript
 const {AutoLanguageClient, getExePath} = require('atom-languageclient')

lib/utils.ts

@@ -1,4 +1,5 @@
 import { join, resolve } from 'path';
+import  { existsSync } from 'fs';
 import {
   Point,
   TextBuffer,
@@ -114,8 +115,10 @@ export function promiseWithTimeout<T>(ms: number, promise: Promise<T>): Promise<
 }
 
 
-/** Finds an exe file in the package assuming it is placed under `rootPath/platform-arch/exe`
- * For example on Windows x64, if the `exeName` is `serve-d`, it returns the absolute path to `./bin/win32-x64/exeName.exe`
+/** Finds an exe file in the package assuming it is placed under `rootPath/platform-arch/exe`. If the exe file did not exist,
+ * the given name is returned.
+ * For example on Windows x64, if the `exeName` is `serve-d`, it returns the absolute path to `./bin/win32-x64/exeName.exe`, and
+ * if the file did not exist, `serve-d` is returned.
  * @param exeName name of the exe file
  * @param rootPath the path of the folder of the exe file. Defaults to 'join("bin", `${process.platform}-${process.arch}`)'
  * @param exeExtention the extention of the exe file. Defaults to `process.platform === "win32" ? ".exe" : ""`
@@ -125,5 +128,10 @@ export function getExePath(
  rootPath = join("bin", `${process.platform}-${process.arch}`),
  exeExtention = process.platform === "win32" ? ".exe" : ""
 ): string {
- return resolve(join(rootPath, `${exeName}${exeExtention}`));
+ const exePath = resolve(join(rootPath, `${exeName}${exeExtention}`));
+ if (existsSync(exePath)) {
+   return exePath
+ } else {
+   return exeName
+ }
 }

test/utils.test.ts

@@ -3,6 +3,8 @@ import { createFakeEditor } from './helpers';
 import { expect } from 'chai';
 import { Point } from 'atom';
 import { join } from 'path'
+import * as fs from 'fs'
+import * as sinon from 'sinon'
 
 describe('Utils', () => {
   describe('getWordAtPosition', () => {
@@ -34,21 +36,37 @@ describe('Utils', () => {
 
   describe('getExePath', () => {
     it('returns the exe path under bin folder by default', () => {
-      const exePath = Utils.getExePath('serve-d');
       let expectedExe = join(process.cwd(), 'bin', `${process.platform}-${process.arch}`, 'serve-d');
       if (process.platform === 'win32') {
         expectedExe = expectedExe + '.exe';
       }
+
+      const fsMock = sinon.mock(fs);
+      fsMock.expects('existsSync').withArgs(expectedExe).returns(true);
+
+      const exePath = Utils.getExePath('serve-d');
       expect(exePath).eq(expectedExe);
+
+      fsMock.restore();
     })
     it('returns the exe path for the given root', () => {
       const rootPath = join(__dirname, `${process.platform}-${process.arch}`);
-      const exePath = Utils.getExePath('serve-d', rootPath);
       let expectedExe = join(rootPath, 'serve-d');
       if (process.platform === 'win32') {
         expectedExe = expectedExe + '.exe';
       }
+
+      const fsMock = sinon.mock(fs);
+      fsMock.expects('existsSync').withArgs(expectedExe).returns(true);
+
+      const exePath = Utils.getExePath('serve-d', rootPath);
       expect(exePath).eq(expectedExe);
+
+      fsMock.restore();
+    })
+    it('returns the exe name if the file does not exist under rootPath', () => {
+      const exePath = Utils.getExePath('python');
+      expect(exePath).eq('python');
     })
   })
 });