[DX] Show a message if server:start is missing pcntl

[weaverryan]

Hi guys!

We now have the server:start and server:stop commands, but they require the pcntl extension. If this extension is not available, the isEnabled() function return false, so the commands are completely not available.

I think this may cause "wtf" moments for users - especially if they're following docs that say to use server:start. Instead, I'd propose:

1. Removing the pctnl check from isEnabled
2. Checking for pcntl inside execute() and returning a very clear message if it is missing:

This command needs the pcntl extension to run. You can either install this, or use the server:run command instead to run the built-in web server.

Or alternatively we could actually say:

This command needs the pctnl extension to run. Since this extension is not installed, we'll instead start the built-in web server using the server:run command

... and then we would actually call the server:run command for them.

Also, why not print a message at the bottom of server:run that says:

Quick the server with CONTROL+C.

I've "borrowed" the language even from Django (https://docs.djangoproject.com/en/1.7/intro/tutorial01/#the-development-server), so there is some precedence for that :).

ping @xabbuh

[xabbuh]

@weaverryan I like your proposal 👍

[stof]

This adds a question about the usefulness of the isEnabled() feature for commands. Is it better to hide commands which cannot be used, or to display them and to fail when trying to use them ? We are already hiding server:run on 5.3 for instance.

and then we would actually call the server:run command for them.

I'm not sure about this, as it would mean that we would block the terminal now, while the user asked to run a command which was not blocking it (thus, running a command from another one is kind of painful).

[hhamon]

Shall we introduce a new protected method to define an explanation message of why the command cannot be run if you try to run it while isEnabled() returns false? I'm not sure if it's possible either to run of command that is not enabled...

[stof]

@hhamon no you cannot. disabled commands are excluded from the command search in the application. In practice, it looks the same than not registering the command at all (except that the logic can be dynamic)

[xabbuh]

I think it's okay to make an exception for the server commands to be shown if the PCNTL extension. This really improves the developer's experience when they are at least able to execute commands that have an important part in the documentation (not yet but we are working on this).

However, I agree that we shouldn't start the server:run command automatically. The user probably triggered the server:start command because they didn't want to block the current terminal. Executing server:run then would be really unexpected. As long as we point them to the server:run command in the error message that will be enough from my point of view.

[weaverryan]

So I think we have some agreement:

1. Always enable the command, but throw a nice exception message if they're missing the PCNTL extension.

2. Include directions on that exception message that suggest using server:run instead.

3. Do not automatically try to server:run.

We'll definitely want this for 2.6 :).

[xabbuh]

@weaverryan I think you meant server:run in 2) and 3), didn't you?

[weaverryan]

@xabbuh Yes thanks - I fixed my comment!

[fabpot]

👍

[xabbuh]

see #12253