It is not clear that require "<plugin>" should not be used in stages; warning doesn't help

[mattbrictson]

From @ethicalmohit in #1904 (comment)

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I was confused with the below message, As which plugin it is taking about and was ignoring it almost because it says its just a warning. It says that the problem is with deploy.rb, I was looking into it. [The offending file was actually deploy/dev.rb (a stage).] Later on, I tried adding another thing which required many other plugins to be included in Capfile and it works. It seems to be the convention than a rule.

WARNING: load:defaults has already been invoked and can no longer be modified.
Check that you haven't loaded a Capistrano plugin in deploy.rb by mistake.
Plugins must be loaded in the Capfile to initialize properly.

[leehambley]

Thanks for picking this up @mattbrictson - maybe we should simply prevent the behaviour and exit with a fatal error. Something akin to the growing trend of making compiler warnings fatal.

• https://blog.mozilla.org/nnethercote/2017/07/05/how-we-made-compiler-warnings-fatal-in-firefox/
• https://golang.org/doc/faq#unused_variables_and_imports
• etc

Maybe we simply blow up if someone reaches that line, and explain why?

[mattbrictson]

Yes, this warning has been in Capistrano for a few versions now, so it is probably safe to promote it to a fatal error. Ideally it would also print the offending file and line number (e.g. in deploy/production.rb), although that might be more difficult.

[will-in-wi]

Looks like this blows up already. Is there more to do on this ticket?

https://github.com/capistrano/capistrano/blob/master/lib/capistrano/immutable_task.rb#L25
https://github.com/capistrano/capistrano/blob/master/spec/lib/capistrano/immutable_task_spec.rb#L28

[mattbrictson]

Maybe the thing to do here is to change WARNING to ERROR in the text. It is not really a warning if it causes an uncaught exception. 😄