Add ability to execute post-install/post-update command event handlers from included files

[jjtroberts]

Is there any way to execute scripts from composer.local.json? I trying to allow custom sites to add additional themes and ensure that theme is activated after install or update. Perhaps with an option to append or override scripts from the parent composer.json file?

[bd808]

Looking at the main Composer entry point, script config is processed very early before delegating to Symfony\Component\Console\Application to process the command line arguments and choose the Command to execute. The current upstream implementation directly reads and parses the root composer.json. I don't see any way to modify the Commands that are registered via a plugin.

[bd808]

It probably would be possible to call post-install/post-update actions that were declared in an included composer.json file. If nothing else, composer-merge-plugin could call such scripts itself when it is called for those events.

[jjtroberts]

Thanks for taking a look at this. I really just need a way to call post-instal/post-update actions if they exist in an included composer.json file. Our default composer.json installs a base theme, and the included composer.json offers the ability to install a different version of that base theme. Having the means within composer to activate the included theme would be immensely helpful.

[bd808]

A reasonable first attempt at this feature would be to:

• Add a feature flag to enable/disable calling script event handlers
  • I think I would prefer to leave this flag disabled by default and make the root composer.json owner explicitly enable it. I'd be willing to listen to arguments as to why enabled by default would be better behavior for end users.
• Collect list of handlers registered in included/required files
• Call handlers for select events as part of composer-merge-plugin's handling of the same event:
  • pre-install-cmd
  • post-install-cmd
  • pre-update-cmd
  • post-update-cmd

I don't have any time at the moment to work on adding this functionality, but I would be more than happy to review a pull request implementing it.

[jjtroberts]

Making progress. I have a feature flag set to false by default, but when set to true it allows MergePlugin.php to retrieve a list of handlers registered in an included file (haven't tested recursive yet). I could use some advice at this point regarding what to do with the resulting array of scripts. How and where do I execute them?

[bd808]

The collected scripts would be executed from the corresponding event handler in MergePlugin. The logic to call a handler is in Composer's EventDispatcher class. You already have the Event to dispatch passed into the compsoer-merge-plugin handler.

The easiest thing to do might be to introduce a subclass of Composer\EventDispatcher\EventDispatcher so you can get at the protected doDispatch method. Then you'd just need to call addListener for each of the callbacks you found and redeliver them locally available event.

[jjtroberts]

Been so long since I've done OO programming. This is out of my league at the moment. I probably need to just allow Jenkins to do the automation and let composer do what it is good at.

This works for my use-case, but it is a hack: https://github.com/gd-jroberts/composer-merge-plugin/commit/de251a33308ccf12b0aa33ca5b4e37bd259a0210

[bd808]

At least partially handled by merge-scripts (#135 & #136) and 586ae1edd4d9492eaaf8fb21ad8ad86306d02b3d where we started hooking Composer 1.1's INIT event.