--yes and --no-interaction do not behave identically

[danepowell]

I'm using Drush 9.0.0-beta7.

According to docs, previous comments, and this issue, the --yes and --no-interaction options should behave identically. In practice, they do not, at least for the site install command.

drush si --yes installs a site without any further interaction from the user, because it assumes a 'yes' response to whether to drop the database prior to install
drush si --no-interaction fails because it assumes a 'no' response to whether to drop the database

Ironically, for the moment this is actually a good thing, because if both of these were to behave like --no-interaction and assume 'no', there would be no way to force a site install! But we definitely need to figure out what the intended behavior is here.

[greg-1-anderson]

Hm, I prefer the behavior you describe. If this is repeatable, we should change the docs.

This is handled here: https://github.com/drush-ops/drush/blob/master/src/Style/DrushStyle.php#L14

Symfony defines --no-interaction as "answer all questions using the default value". The downside of replicating this behavior everywhere is that --yes would not necessarily cause a confirmation to pass if the default value is 'no'. However, the confirm method above is derived from SymfonyStyle, so as long as we can inject our object into our dependencies, then the behavior will be consistent.

So, lets fix the docs.

[weitzman]

I think this is a happy accident that may need to be fixed. Specfically, look at how we set the value of DRUSH_NEGATIVE at

drush/src/Preflight/LegacyPreflight.php

Lines 103 to 114 in 3a6d8d7

	$no = $input->getOption('no-interaction', false);
	$pipe = $input->getOption('pipe', false);
	$quiet = $input->getOption('quiet', false);
	$simulate = Drush::simulate();
	drush_set_context('DRUSH_VERBOSE', $verbose || $debug);
	drush_set_context('DRUSH_DEBUG', $debug);
	drush_set_context('DRUSH_DEBUG_NOTIFY', $verbose && $debug);
	drush_set_context('DRUSH_SIMULATE', $simulate);
	// Backend implies affirmative unless negative is explicitly specified
	drush_set_context('DRUSH_NEGATIVE', $no);

This overloading of --no-interaction is going to bite us later, no?

[weitzman]

See #3084 where I stop overloading -n|--no-interaction and also modernize a bit

[weitzman]

Lets discuss in #3084.