Dynamic Dependencies for larger library

Question

Let's say i have a library that contains multiple parts, say A and B.

In an application I require that library but use part A only. That is defined thru an config setting in the application that can read dynamically.

Now A and B have different requirements to other packages.

How could I only require A dependencies if only A is used?

The obvious answer would be to split that library into two libraries. But the library is currently not split and that would require a big effort of work and would completely change the workflow - which we don't want. Think of eg. Zend Framework which is also only a single library.

Answer 1

The best way to do this is by removing both A and B from your "require" section and adding them to the "suggest" section instead (including a short description):

{
    ...
    "suggest": {
        "a/a": "to be able to use X (1.*)",
        "b/b": "to be able to use Y (~1.3)"
    }
}

Now, when a user installs the package, it'll get a message showing the suggested packages:

package/package suggests installing "a/a": to be able to use X (1.*)
package/package susgests installing "b/b": to be able to use Y (~1.3)

The user installing the package should now determine theirselves if they want to also require "a/a" or "b/b".

---

While this solution is one of the most used and most simple, it is a better option to split the package. See also "There’s no such thing as an optional dependency"