On 17.02.2012 14:24, Zhihao Yuan wrote:
I regard this as a wrong practice. Here is why:
1. The way you specify the version in LIB_DEPENDS has NO relation with
how the port link to the lib. The port can link to the major version
(pkg-config), or the .so, etc.
I'm sorry, I can not parse the above part. Perhaps, a live example is in order.
2. One responsibility of the ports system is to protect the user from
suffering from running a software which links to a ABI incompatible,
hence, wrong shared library.
This is a made-up non-reason, sorry. The only way to get into an ABI
incompatibility is to have -- at the time of the port building -- header-files
declarations from one version of a library and implementation(s) from another.
Avoiding such situations is out of the scope of the ports-system and this
discussion.
Again, try to come up with a real-life example of how my proposal would break
ABI for an actual user... You can not.
3. "Known to cause problem"? Can I infer ""you can predict the future"
from that?
Yes, you can. Well-knowing the past 15 or so years of the ports-system, I can
predict some aspects of the future. For example:
* committers will continue to forget to update some of the umpteen instances
of LIB_DEPENDS=foo.X in various ports, when bumping up major version of foo.
* committers will continue to /mindlessly/ bump-up these umpteen instances --
without actually verifying, that the new version of foo is still acceptable
to all of those dependants.
* port-building will remain unduly difficult because of the wide-spread
mindless (mis)use of the major shlib-number in LIB_DEPENDS. Consider the
following scenario (substitute any of "png", "jpeg", "xml", etc. for "foo"):
1. You build a shiny new machine -- with the desktop of your choice (KDE,
Gnome, Xfce - whatever) from ports. Hours of build-time interrupted by
occasional `config' screens...
2. A week later you update your ports tree -- which sees version-bump of
libfoo.
3. You try to add a foo-using program bar to your computer -- and fail,
because the bar-port now insists on the very latest version of libfoo.
Not because the maintainer of bar determined, that the earlier versions
are bad -- simply because the maintainer of foo went through all
dependents and updated the LIB_DEPENDS lines in all of them, as is the
current sad practice.
4. You now have to either portupgrade libfoo -- which means, your desktop
will be using libfoo.N and the newly-built bar will be using libfoo.N+1
(inefficient and sometimes a source of problems in its own), or go
through rebuilding all of the foo-using ports again...
So, to link to a version explicitly should be the default. Only a
library behaviors "good" in its development history can be considered
to use it's libname only in LIB_DEPENDS.
I'm not sure, what you mean by "link to a version". Once again, I beg you to
offer a live example. Yours,
-mi
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