Version dependencies: Support versions with "extra" (alpha, beta, rc, etc)

#211747-78: Allow specifying version information as part of module dependencies

PHP's version_compare() already handles extra identifiers in version numbers properly.

The only issue we'd have to tackle here is to transform branch versions, i.e. 2.x, into a comparable version number for version_compare(), because 2.x is interpreted completely different than 2.1-beta2. The most trivial and most dirty way would be to transform 2.x into 2.999 internally for comparison. That way:

2.x >= 2.0              === FALSE
2.999 >= 2.0            === TRUE
2.999 >= 2.0-beta1      === TRUE
2.0-beta1 >= 2.0-alpha  === TRUE
2.0-beta2 >= 2.0-beta1  === TRUE

sun, we already have code to handle 2.x -- and yes it can be changed so that preg is not necessary but that's a whole another issue -- and there is no 2.x-beta or some such so your followup does not pertain to this issue.

testing version compare for arbitrary strings:

$a = '2.3-foo2';
$b = '2.3-foo1';
var_dump(version_compare($a, $b, '>'));
$a = '2.3-dev1';
$b = '2.3-foo1';
var_dump(version_compare($a, $b, '>'));

both are TRUE.when using the same version string the comparison works well. dev < alpha = a < beta = b < RC < pl says the documentation which can now amend as arbitrary string < dev < alpha = a < beta = b < RC < pl .

Edit: I read the relevant C code and it converts these special strings to numbers so the order is:
any string not in the following list < dev < alpha = a < beta = b < RC = rc < # < pl = p

Our version info is 6.x-2.x-dev, not 6.x-2.3-dev.

Needs tests. We had TONS of fun with version_compare.

This looks good to me. Should we add a couple more tests? I.e. comparing rc1 and rc2, comparing unstable with alpha, etc?

Derek, the >= and the < are dealt with the resetting of minor and extra. And there is a comment IMO which already explains that but I will check.

More tests, more comments.

This is a whole new approach because a question from Nick Lewis made me test 2.0 vs 2.x in version compare to find that numbers are higher than strings. Yay. Simplify++

Now, that's some comment...

Simplified comments -- we do not need a novel about internal implementation details. There is enough comment so that people can figure out if they want.

Looks great, with one question.

What is the difference between the = and == operator? I couldn't find any docs on php.net on this, and not quite sure what it could be.

Since we allow this op, and special case it for .x version number, we should probably have a test for it.

Otherwise, RTBC

Actually after looking at this, I'm not sure the == operator makes much sense. In the case of 2.x it is identical to =.

With specific versions (not .x branches), we require the point release in dependency strings anyway*, and packaged releases will always have it as well, and we don't allow patch level, so there is no need to say 2.0.0 vs. 2.0 aren't equal.

*(>=2) doesn't work, must be 2.x

== and = are the very same. Why not allow both? version_compare allows both. There's not much point in testing that.

That looks MUCH better.

I made some more minor polish to the comments and committed to HEAD.

It looks like mikey_p was looking at a different hunk of this file that the patch doesn't touch. We could open a separate issue for that.