How can I get the WP-CLI eval-file command to report errors to stderr?

Adding the following lines to the top of your script, as recommended in Github issue, should report any runtime errors:

ini_set( 'display_errors', 1 );
error_reporting(E_ALL);

However, it will not report syntax errors, which is a big headache as you try to write your script. This is my workaround for that:

• Add following line to bottom of my script:

  // my-script.php
  <?php
  ini_set( 'display_errors', 1 );
  error_reporting(E_ALL);
  
  global $wpdb;
  
  // rest of script
  
  echo "Script complete.\n";
  

• Make changes to script.

  // my-script.php
  <?php
  ini_set( 'display_errors', 1 );
  error_reporting(E_ALL);
  
  global $wpdb;
  
  // rest of script
  derp-some-invalid-syntax...
  
  echo "Script complete.\n";
  

• Run script:

  $ wp --debug eval-file my-script.php
  

• If I don’t see Script complete., run php linter:

  $ php -l my-script.php
  
  Parse error: syntax error, unexpected '.' in my-script.php on line 7
  Errors parsing my-script.php
  

• Fix syntax errors.

• Re-run script.