[Feature request] replaced-by key

[greg0ire]

Some packages, like symfony/polyfill-mbstring do things only if an extension like ext-mbstring is missing. I think a configuration key that would act as the inverse of replaces could be useful in that kind of case.

[javiereguiluz]

How would this work for packages like symfony/polyfill-php56 where the install rule is: "ignore this package if PHP version is PHP 5.6 or higher".

[greg0ire]

@javiereguiluz you're right, it should probably not be that simple. I think it could look like this:

    "name": "symfony/polyfill-php56",
    "replaced-by": {
        "php": ">=7.0"
    }

or

    "name": "symfony/polyfill-mbstring",
    "replaced-by": {
        "ext-mbstring": "*"
    }

[Seldaek]

Closing as I don't think this is likely to happen. It's too complex for what it brings IMO, installing a bit of code that's not needed isn't the worst problem.