fix(misc): guard against failure to decode file in migration

packages/nx/src/migrations/update-16-8-0/escape-dollar-sign-env-variables.ts

@@ -1,3 +1,4 @@
+import { logger } from '../../utils/logger';
 import { Tree } from '../../generators/tree';
 import { getProjects } from '../../generators/utils/project-configuration';
 
@@ -59,13 +60,23 @@ function parseEnvFile(tree: Tree, envFilePath: string) {
  if (!tree.exists(envFilePath)) {
  return;
  }
+
  let envFileContent = tree.read(envFilePath, 'utf-8');
+ if (!envFileContent) {
+ // envFileContent is null if we fail to read the file for any reason
+ // e.g. the file is not utf-8 encoded
+ logger.info(
+ `Unable to update ${envFilePath}. Nx interpolates environment variables in the form of $VAR_NAME. To escape the dollar sign, use \\$VAR_NAME.`
+ );
+ return;
+ }
+
  envFileContent = envFileContent
  .split('\n')
  .map((line) => {
  line = line.trim();
 
- if (!line.includes('$')) {
+ if (!line || !line.includes('$')) {
  return line;
  }