Bug#376920: lintian: missing-build-dependency cdbs even though depends on dh-make-php

[Russ Allbery <rra@debian.org>]

Charles Fry <cfry@debian.org> writes:

>>> As for dh-make-php, as one of the maintainers I can vouch that the only
>>> reason to depend on dh-make-php at build time is to use the cdbs module
>>> pear.mk.
>> 
>> But you're also using other cdbs modules not supplied directly by
>> dh-make-php, correct?  Certainly, the template generated by dh-make-php
>> does so.

> True enough.

I can see various philosophies about this, and I'm happy to be persuaded
if what I'm saying doesn't make sense, but the general rule of thumb I've
been using is that packages shouldn't rely on transitive dependencies to
pick up packages that they use directly.  In other words, if a package
calls patch directly in debian/rules, it should Build-Depend on patch,
even if it also Build-Depends on a patch management system like quilt that
in turn depends on patch.  If a package links directly with some library,
it should depend on the appropriate -dev package, even if another library
it also uses pulls in that -dev package.

There are some (maybe even many) cases where such reliance on transitive
dependencies would be safe, but I think it's an area that benefits from a
rule of thumb, and it makes it a lot easier to write things like lintian
without a surfeit of special cases.

-- 
Russ Allbery (rra@debian.org)               <http://www.eyrie.org/~eagle/>