Unclear error message when plugin install fails due to plugin not found

[edmorley]

Do you want to request a feature or report a bug?

Bug

What is the current behavior?

Attempting to installing a non-existent plugin fails without a clear error.

$ heroku plugins:install this-plugin-does-not-exist
Installing plugin this-plugin-does-not-exist... !
$

ie: The exclamation mark is easy to miss (I thought the command had succeeded), and the reason for the install failure is not specified.

What is the expected behavior?

Something like:

$ heroku plugins:install this-plugin-does-not-exist
Installing plugin this-plugin-does-not-exist... !
Error: Plugin this-plugin-does-not-exist not found! (Tried `@heroku-cli/this-plugin-does-not-exist`, ...)

This is using heroku/7.26.2 darwin-x64 node-v11.14.0

[RasPhilCo]

The yarn error is being swallowed. We likely need to surface it or at least show something more useful.

[br4e]

$ heroku plugins:install heroku-builds
Installing plugin heroku-builds... !
$

This is still an issue and still extremely frustrating @RasPhilCo