[development] Installation -- Can A Module "Refuse" To Be Installed?

Arnab Nandi arnabdotorg at gmail.com
Sun Apr 9 01:59:02 UTC 2006

Well, I appreciate someone is finally thinking about dependencies. I
had a look at Nedjo's code, here are some questions:

0) Do you handle module versions? I don't see anything in the code.
How do i say, "I depend on moduleA versions > 10, but not more than
1) How is an upgrade handled? Say module A required module B on
install. Does it again require it during upgrade, or can the module be
missing? (think "import" modules vs "actual" modules)
2) The code auto-disables stuff; which is dangerous. I would provide
an additional disable hook for the faulty module to recover from
problems before being killed. Say we had a spam-clean.module,
depending on search.module for finding to clean nodes. Now an admin
accidentally disables search.module because spam bots are wreaking
havoc, and this disables spam-clean, which foobars the website.

A good place to look for inspiration is APT, instead of reinventing the wheel.

(I think i've mentioned this before when the topic came up)


On 4/8/06, Nedjo Rogers <nedjo at islandnet.com> wrote:
> >    * Dependencies are an issue for some of the stuff I'm installing. It
> > would be a good thing if the .install could detect that a
> >      needed module was not present, and in that case, put up an error
> >      message and refuse to install.  Is there a mechanism to do this
> >      currently?
> Based on code Chad (hunmunk) posted, I've drafted a Dependencies module,
> http://drupal.org/node/57071, that tests for dependencies and doesn't allow
> modules to be installed if their dependencies are missing. You could include
> a _dependencies() hook, e.g.
> modulename_dependencies() {
>   return array('module1', 'module2');
> }
> Of course, that will work only if a site has the Dependencies module
> installed and enabled.
> Or else feel free to just add your dependencies to the default array in the
> dependencies/dependencies.module (this goes for any other module developer).
> Robert Douglass suggested, and I concur, that it woud be useful to
> distinguish between hard and soft dependencies, but I haven't yet
> incorporated his suggestion into the module.
> Nedjo


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