I agree. Dropping support for PHP4 constitutes a BC break. Think of
Joe Developer, who upgrades PEAR-1.4 to PEAR-1.5. Oops, PEAR breaks.
This is what defines a BC break.
No, it's not. A BC break is when the *API* changes, not when a dependency changes. If this was the case then adding any new dependency would constitute a BC break, which is just silly. As Greg already stated the PHP5 version of PEAR won't install on a PHP4 system.
Now, it is certainly possible that you can add a PHP5 dependency to
the PEAR package.xml, but this is only a quick fix for the above
problem. Anyone using PHP4 will be shut out from updates and bug fixes
in the 1.x line.
So is anyone using anything before PHP version 4.2 - what's your point?
To move to only PHP5, PEAR will have to move to PEAR2 as this is a BC
break. You're welcome to take the current code, make it PHP5-only, and
rename it PEAR2, but I doubt this is what you want.
That's not true for the reason that requiring a newer version of something isn't a BC break in the API. Since when do BC's mean that you can't move up a dependency? Is that anywhere in the docs? If not then you need to propose and pass an RFC if you want every PHP5 package to be Foo2 instead of Foo (despite the API NOT changing).
Good luck with that ...
--Joe