Compatibility with Drush 8 when installing via composer

[csandanov]

The latest RC version of drupal console (1.0.0-rc16) depends on symfony/var-dumper v3.2.6. However, the latest stable drush (8.1.0) requires ~2.7 of var-dumper. So, they are not compatible when installing via composer.

Drush is a de-facto standard tool and many contrib modules already integrated with it. What is your standing on this compatibility issue? What is the recommended workaround? Do not use composer to install console or drush?

[jmolivas]

Drupal Console does not require symfony/var-dumper

> composer why symfony/var-dumper
drush/drush  8.1.10  requires  symfony/var-dumper (~2.7)
psy/psysh    v0.8.3  requires  symfony/var-dumper (~2.7|~3.0)

What I see is drush and drupal console requires psy/psysh and drush and psy/psysh requires symfony/var-dumper and this may be causing the conflict.

[Chi-teck]

Per the above note both drush and psych can work with var-dumper ~2.7. I am not sure why composer fails to resolve this.

The workaround is installing these packages at once.
composer require drupal/console:~1.0 drush/drush

[csandanov]

@Chi-teck thanks, the workaround helped.

Just in case the output when I install drush separately after installing console rc-16:

Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Conclusion: don't install drush/drush 8.1.10
    - Conclusion: don't install drush/drush 8.1.9
    - Conclusion: don't install drush/drush 8.1.8
    - Conclusion: don't install drush/drush 8.1.7
    - Conclusion: don't install drush/drush 8.1.6
    - Conclusion: don't install drush/drush 8.1.5
    - Conclusion: don't install drush/drush 8.1.4
    - Conclusion: don't install drush/drush 8.1.3
    - Conclusion: don't install drush/drush 8.1.2
    - Conclusion: don't install drush/drush 8.1.1
    - Conclusion: remove symfony/var-dumper v3.2.6
    - Installation request for drush/drush ^8.1 -> satisfiable by drush/drush[8.1.0, 8.1.1, 8.1.10, 8.1.2, 8.1.3, 8.1.4, 8.1.5, 8.1.6, 8.1.7, 8.1.8, 8.1.9].
    - Conclusion: don't install symfony/var-dumper v3.2.6
    - drush/drush 8.1.0 requires symfony/var-dumper ~2.7 -> satisfiable by symfony/var-dumper[v2.7.0, v2.7.1, v2.7.10, v2.7.11, v2.7.12, v2.7.13, v2.7.14, v2.7.15, v2.7.16, v2.7.17, v2.7.18, v2.7.19, v2.7.2, v2.7.20, v2.7.21, v2.7.22, v2.7.23, v2.7.24, v2.7.25, v2.7.3, v2.7.4, v2.7.5, v2.7.6, v2.7.7, v2.7.8, v2.7.9, v2.8.0, v2.8.1, v2.8.10, v2.8.11, v2.8.12, v2.8.13, v2.8.14, v2.8.15, v2.8.16, v2.8.17, v2.8.18, v2.8.2, v2.8.3, v2.8.4, v2.8.5, v2.8.6, v2.8.7, v2.8.8, v2.8.9].
    - Can only install one of: symfony/var-dumper[v2.7.0, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.1, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.10, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.11, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.12, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.13, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.14, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.15, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.16, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.17, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.18, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.19, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.2, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.20, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.21, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.22, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.23, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.24, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.25, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.3, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.4, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.5, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.6, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.7, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.8, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.7.9, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.0, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.1, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.10, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.11, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.12, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.13, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.14, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.15, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.16, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.17, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.18, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.2, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.3, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.4, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.5, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.6, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.7, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.8, v3.2.6].
    - Can only install one of: symfony/var-dumper[v2.8.9, v3.2.6].
    - Installation request for symfony/var-dumper (locked at v3.2.6) -> satisfiable by symfony/var-dumper[v3.2.6].


Installation failed, reverting ./composer.json to its original content.