This is a great module, thanks!

drush dmu-analyze

works fine, but I get:

drush dmu-upgrade realistic_dummy_content
Indexing...done.
PHP Fatal error:  Call to a member function previousToken() on a non-object in /srv/drupal/www/modules/drupalmoduleupgrader/vendor/grom358/pharborist/src/Formatter.php on line 160
Drush command terminated abnormally due to an unrecoverable error.                                                                [error]
Error: Call to a member function previousToken() on a non-object in
/srv/drupal/www/modules/drupalmoduleupgrader/vendor/grom358/pharborist/src/Formatter.php, line 160

I got no errors upon installation:

 composer install
Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
  - Installing cebe/markdown (dev-master f89dc1d)
    Cloning f89dc1da1fc6823f0286d6cad736a642efd0f59e

  - Installing phpdocumentor/reflection-docblock (2.0.3)
    Downloading: 100%         

  - Installing grom358/pharborist (dev-master 026db8d)
    Cloning 026db8d275231be63913b50fed69342f4c514d27

  - Installing symfony/filesystem (2.6.x-dev a1f566d)
    Cloning a1f566d1f92e142fa1593f4555d6d89e3044a9b7

  - Installing symfony/finder (2.6.x-dev 1651333)
    Cloning 16513333bca64186c01609961a2bb1b95b5e1355

phpdocumentor/reflection-docblock suggests installing dflydev/markdown (1.0.*)
phpdocumentor/reflection-docblock suggests installing erusev/parsedown (~0.7)
Generating autoload files

I am running this on Ubuntu in this Docker container.