[asdf-devel] In defense of ASDF & Semantic versioning
vseloved at gmail.com
Wed Nov 20 13:34:01 UTC 2013
I think, you're both right. :)
I have a similar experience of migrating a large Java application through
changes of versions of Jetty from 6th to 9th, and it was much less painful
when the namespaces were changed (between v. 6 and 7 if I'm not mistaken)
for the points mentioned by Anton. So I think, it indeed makes sense to
create, say, hunchentoot2 if there's going to be again a serious
incompatible API change, like the transfer from 0.X to 1.X. (But a transfer
from 0.X to 1.X is an exception here, because it is assumed that until v.1
the software is not stable).
At the same time, if you make a small "local" API change, it often doesn't
justify creating a new package & system, because there will be more total
inconvenience for those who aren't affected (the majority) to migrate to
the new version than for those who are affected to change their code.
So it all just boils down to common senses, some level of discipline and
the amount of change some system really needs to go through intrinsically.
My guess is that for the vast majority of libraries such dramatic version
transitions may happen once in several years, and it totally makes sense
for me to do a new namespace/system for that.
skype, twitter: vseloved
On Wed, Nov 20, 2013 at 2:50 PM, Anton Vodonosov <avodonosov at yandex.ru>wrote:
> 19.11.2013, 23:41, "Robert P. Goldman" <rpgoldman at sift.info>:
> > it's too radical
> It's not radical, actually my proposal is very similar to yours
> > It's like having a purely functional programming language
> Yes, I see this as an FP analogy too and expect that avoiding
> mutations and destructive changes will simplify life
> for developers.
> > with no garbage-collection!
> Why without garbage-collection? We are not leaking any resources.
> > We'd be left with heaps of unmaintained and unmaintainable
> > versions of basic-lib floating around in the worse case.
> The amount of library versions does not change in the approach
> I propose. But versions with different APIs are have different names.
> And we deal only with versions we use, and can forget about any
> other versions.
> > Also, the two different libraries won't live happily in the same lisp
> > image, unless they change package
> Wait, I do propose to change package
> > at every release
> at every API incompatible change (in other words, for every new API).
> > This approach seems like it will be such a monumental pain for the
> > library maintainers,
> What pain do you mean? It's a zero cost solution. It requires no
> additional efforts from library maintainer, and even no special
> support from ASDF and other tools.
> > and anyone who wishes to upgrade his/her client program
> > from basic-lib to basic-lib2
> The client job remains the same: if he wants to migrate to
> the new API he rewrites parts of his code using new functions.
> Nothing above that.
> Moreover, as client can have access to both APIs simultaneously,
> he can sometimes migrate partially: leave his old tested code
> as is (using basic-lib), but in the places where he needs
> new functionality he calls basic-lib2.
> So, client can benefit from new features without investing
> efforts into rewriting and retesting code.
> > I'd argue that having two versions of the same library *in the same
> > image* is too demanding a target.
> It's not a target. The target is to not break clients.
> It's rather a tool to achieve this target, or a pleasant side-product
> of a cheap decision to name different things differently.
> Please think about this approach a little more.
> IMHO this approach is convenient and I would recommend
> it as the first thing to consider to anyone who is going
> to change API of a public library.
> Am I missing anything?
> Best regards,
> - Anton
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