Disable creation of cmdShim PowerShell shims because they don't work and cause problems (#6954)

* Disable creation of cmdShim PowerShell shims because they don't work and cause problems

* Fix PowerShell test on non-Windows platforms

* Fix lint error

* Update CHANGELOG.md

Author: briman0094

CHANGELOG.md

@@ -4,6 +4,10 @@ Please add one entry in this file for each change in Yarn's behavior. Use the sa
 
 ## Master
 
+- Reverts a behavior causing boggus interactions between PowerShell and `yarn global`
+
+  [#6954](https://github.com/yarnpkg/yarn/pull/6954) - [**briman0094**](https://github.com/briman0094)
+
 - Fixes a bug where non-zero exit codes were converted to a generic 1 when running `yarn run`
 
   [#6926](https://github.com/yarnpkg/yarn/pull/6926) - [**Kyle Fang**](https://github.com/zhigang1992)

__tests__/commands/global.js

@@ -90,6 +90,23 @@ test.concurrent("shouldn't expose unwanted binaries", async (): Promise<void> =>
   });
 });
 
+test.concurrent("shouldn't create powershell shims", async (): Promise<void> => {
+  const tmpGlobalFolder = await createTempGlobalFolder();
+  const tmpPrefixFolder = await createTempPrefixFolder();
+  const flags = {globalFolder: tmpGlobalFolder, prefix: tmpPrefixFolder};
+  const isWindows = process.platform === 'win32';
+  return runGlobal(['add', 'react-native-cli'], flags, 'add-with-prefix-flag', async config => {
+    expect(await fs.exists(path.join(tmpPrefixFolder, 'bin', 'react-native'))).toEqual(true);
+    expect(await fs.exists(path.join(tmpPrefixFolder, 'bin', 'react-native.cmd'))).toEqual(isWindows);
+
+    // Should not have any ps1 shims whatsoever (including erroneous double-extension ones)
+    expect(await fs.exists(path.join(tmpPrefixFolder, 'bin', 'react-native.ps1'))).toEqual(false);
+    expect(await fs.exists(path.join(tmpPrefixFolder, 'bin', 'react-native.ps1.ps1'))).toEqual(false);
+    expect(await fs.exists(path.join(tmpPrefixFolder, 'bin', 'react-native.ps1.cmd'))).toEqual(false);
+    expect(await fs.exists(path.join(tmpPrefixFolder, 'bin', 'react-native.cmd.ps1'))).toEqual(false);
+  });
+});
+
 test.concurrent('bin', (): Promise<void> => {
   const tmpGlobalFolder = getTempGlobalFolder();
   return runGlobal(

src/cli/commands/link.js

@@ -75,7 +75,7 @@ export async function run(config: Config, reporter: Reporter, flags: Object, arg
             reporter.warn(reporter.lang('binLinkCollision', binName));
           } else {
             if (process.platform === 'win32') {
-              await cmdShim(binSrcLoc, binDestLoc);
+              await cmdShim(binSrcLoc, binDestLoc, {createPwshFile: false});
             } else {
               await fs.symlink(binSrcLoc, binDestLoc);
             }

src/fetchers/base-fetcher.js

@@ -81,7 +81,7 @@ export default class BaseFetcher {
           if (process.platform === 'win32') {
             const unlockMutex = await lockMutex(src);
             try {
-              await cmdShim.ifExists(src, `${binDest}/${binName}`);
+              await cmdShim.ifExists(src, `${binDest}/${binName}`, {createPwshFile: false});
             } finally {
               unlockMutex();
             }

src/package-linker.js

@@ -34,7 +34,7 @@ export async function linkBin(src: string, dest: string): Promise<void> {
   if (process.platform === 'win32') {
     const unlockMutex = await lockMutex(src);
     try {
-      await cmdShim(src, dest);
+      await cmdShim(src, dest, {createPwshFile: false});
     } finally {
       unlockMutex();
     }