fix(core): npmrc should be obeyed during nx migrate

packages/tao/src/commands/migrate.ts

@@ -1,5 +1,12 @@
 import { execSync } from 'child_process';
-import { removeSync } from 'fs-extra';
+import {
+  removeSync,
+  writeFileSync,
+  copyFileSync,
+  existsSync,
+  createFileSync,
+  mkdirSync,
+} from 'fs-extra';
 import * as yargsParser from 'yargs-parser';
 import { dirname, join } from 'path';
 import { gt, lte } from 'semver';
@@ -13,6 +20,7 @@ import {
   readJsonFile,
   writeJsonFile,
 } from '../utils/fileutils';
+import { appRootPath } from '../utils/app-root';
 
 type Dependencies = 'dependencies' | 'devDependencies';
 
@@ -439,7 +447,23 @@ function createFetcher() {
     packageVersion: string
   ): Promise<MigrationsJson> {
     if (!cache[`${packageName}-${packageVersion}`]) {
-      const dir = dirSync().name;
+      // Setting up a tmpDir. In order to obey various .npmrc files
+      // this is a bit more complex than it should be. `.npmrc` can be present
+      // in ~/, workspace root, global, or in the npm installation directory.
+      const tmpdir = `${appRootPath}/node_modules/.tmp`;
+      mkdirSync(tmpdir, { recursive: true }); // dirSync fails if tmpdir does not exist yet.
+      const dir = dirSync({
+        tmpdir: tmpdir,
+      }).name;
+      // Creating a package.json in the new tmp directory prevents us from
+      // installing packages in the actual workspace instead of this subdirectory.
+      writeFileSync(`${dir}/package.json`, '{}');
+      // Copy npmrc from workspace root if it exists, so that npm still follows it.
+      const npmrcPath = `${appRootPath}/.npmrc`;
+      if (existsSync(npmrcPath)) {
+        copyFileSync(npmrcPath, `${dir}/.npmrc`);
+      }
+
       logger.info(`Fetching ${packageName}@${packageVersion}`);
       const pmc = getPackageManagerCommand();
       execSync(`${pmc.add} ${packageName}@${packageVersion}`, {