Exported boolean yaml strings are not quoted consistently

[marcvangend]

(Excuse me if this is not the right place to ask, I'm not sure if this is a Drush problem.)

When my colleague exports config with drush cex, some strings are quoted. I think I was able to trace this back to \Symfony\Component\Yaml\Escaper::requiresSingleQuoting(), and the behavior seems to make sense because those strings ('null', '~', 'true', 'false', 'y', 'n', 'yes', 'no', 'on', 'off') could otherwise be interpreted as booleans.

Unfortunately the behavior is not consistent across our team. Sometimes the strings are quoted, sometimes they aren't, so we keep polluting the git history with changed config. We have verified that we use the same Drush version (8.1.10) and Composer version (1.3.2). Since we commit our composer.lock file to git, we also use the same packages. We are not on the exact same PHP7 versions, but looking at the code I think that the PHP version should not matter in this case.

What could be the cause of this? What can I do, or what other information could be relevant to figure out why this is happening? Thank you.

[weitzman]

I am under the vague impression that this can happen when some team members have pecl yaml extension and some don't.

[marcvangend]

Thanks for the tip. I tried to verify on my own machine if this is indeed the problem. It seems that pecl yaml is not the cause; at least it is not with the combination of software versions I tested.

Initial situation:

• My machine does not have the pecl yaml extension installed
• I'm running PHP 7.1.2, Drush 8.1.10, Composer 1.3.2, Drupal 8.2.6, symfony/yaml 2.8.17
• The output of drush cget language.mappings is:

    map:
      no: nb
      pt: pt-pt
      zh: zh-hans
      zh-tw: zh-hant
      zh-hk: zh-hant
      zh-mo: zh-hant
      zh-cht: zh-hant
      zh-cn: zh-hans
      zh-sg: zh-hans
      zh-chs: zh-hans
    _core:
      default_config_hash: EMWe7Yu4Q5eD-NUfNuQAWGBvYUNZPIinztEtONSmsDc
    langcode: nl
  

• When my colleague exports language.mappings, the "no" is quoted:

    map:
      'no': nb
      ...
  

What I tried

• Install the pecl yaml extension, version 2.0.0, with LibYAML version 0.1.7, from my Linux distro's package manager
• Verify that drush is indeed using php with the yaml extension (drush eval "phpinfo();" | grep -i yaml)
• Run drush cget language.mappings with default yaml extension options
• Run drush cget language.mappings with changed yaml extension options (yaml.output_canonical=1, yaml.decode_binary=1, yaml.decode_php=1, yaml.decode_timestamp=1)
• I have not yet checked

Results so far

• In all situations, my output remained the same (not quoted)
• I have not yet checked which extensions are running on my colleagues machine (it's weekend :-))
• I wanted to test with a different (older) version of the pecl yaml extension, but it was not available in the package manager.