Blank or null assets:packages:*:version_strategy does not override default version_strategy

[aaronm-cloudtek]

Q	A
Bug report?	yes
Feature request?	no
BC Break report?	no
RFC?	no
Symfony version	3.2.1

With the following asset package config:

    framework:
        assets:
            version_strategy: 'app.asset.versioning.my_strategy'
            packages:
                alternate:
                    version_strategy: ~    #also tried '' here with the same result

Calls to twig helper asset('path/to/asset.css', 'alternate') are still piped through app.asset.versioning.my_strategy.

I was only able to get the desired behavior by specifying version_strategy: 'assets.empty_version_strategy' for the alternate package.

[stof]

By default, the main version strategy is used for each package, which does not define its own config. setting the strategy to null does not consider it as being defined.

If you want to use an empty version, you should use version: null or version: '' inside your package, to configure a version explicitly.

[aaronm-cloudtek]

Thanks @stof that is a cleaner solution than I came up with. I'd still suggest allowing a null setting to bypass the default strategy for a given package but that's just my opinion.

[xabbuh]

I don't see how that would be possible without breaking BC for users relying on the current behaviour.

[javiereguiluz]

@aaronm-cloudtek although your idea is nice, we cannot implement it because of the reason given by @xabbuh. That's why I'm closing it. However, thanks to your issue, I've realized that we can improve the docs about this option, and we're doing that in symfony/symfony-docs#7519 Thanks!