[drupal-devel] [feature] Dependency system to solve forum without comment problem

chx drupal-devel at drupal.org
Mon Sep 19 04:12:57 UTC 2005

Issue status update for 
Post a follow up: 

 Project:      Drupal
 Version:      cvs
 Component:    system.module
 Category:     feature requests
 Priority:     normal
 Assigned to:  chx
 Reported by:  chx
 Updated by:   chx
 Status:       patch (ready to be committed)

And what could I say that will convince you? 

We are trying to convince contrib authors to work together but it's a
support nightmare because of dependency issues. 

Messages? I fail to see the point. "Warning: you enabled forum but not
enabled comments. Forum won't work" What else would be my answer if
"dang, why you can't do it for me??"


Previous comments:

Sun, 06 Mar 2005 00:55:36 +0000 : chx

Attachment: http://drupal.org/files/issues/depend.patch (3.22 KB)

As discussed on the developer list. This was surprisingly easy. There is
still an issue: t('The configuration options have been saved.') is
displayed more than once if there is a dependency forced module switch
on. I have tried something (you'll see) for some reason it does not

Number of page reloads can be decreased if Drupal could be
reinitialized after system_listing_save instead of redirecting but I
doubt this would be feasible.

Although I marked this is feature request, this is more a usability
issue (for the forum-comment dependency) and as a side effect it is a
useful feature, too (for any other module "bundles").

I want criticism! I'd like to get torn apart by wild animals. Heavy! 
Eaten by some squirrels.


Sun, 06 Mar 2005 01:22:17 +0000 : clydefrog

Forgive me if I'm mistaken, but shouldn't forum_depends return an array?


Sun, 06 Mar 2005 01:26:40 +0000 : javanaut

I think allowing for both required dependencies as well as optional ones
would make it practical for a package management tool to be created.  I
like it, though, and I think being able to programatically enforce (or
at least notify users about) dependencies would assist users who refuse
to RTFM.

>From my drupal-devel comment, here's how I would suggest formatting the

function filestore2_depends() {
 return array('required'=>array('fscache'), 'optional'=>array('taxonomy','comments'));


Sun, 06 Mar 2005 01:29:24 +0000 : chx

If you take a look at module_invoke_all, you will see that a string is
fine, 'cos if you return a string it does $result[]

However, an associative array is not good with module_invoke_all 'cos
for returned arrays there is an array_merge where "If the input arrays
have the same string keys, then the later value for that key will
overwrite the previous one."


Sun, 06 Mar 2005 01:33:55 +0000 : javanaut

Ok, how about it taking a parameter?

function filestore2_depends($dep_type='required') {
$deps = array('required'=>array('fscache'), 'optional'=>array('taxonomy','comments'));
return $deps[$dep_type];


Then, for required dependencies, pass a 'required' argument, and
optional ones could take an 'optional' argument.


Sun, 06 Mar 2005 02:00:27 +0000 : chx

Attachment: http://drupal.org/files/issues/depend_0.patch (3.6 KB)

I would leave associative arrays for the future. As we do not have a
package tool, there is little use of 'optional' -- I'd like to get this
into 4.6

After testing the patch, I have changed something, which I should not
have done, so another version is attached.


Sun, 06 Mar 2005 02:11:13 +0000 : chx

Attachment: http://drupal.org/files/issues/depend_1.patch (4.37 KB)

This one should really work...


Sun, 06 Mar 2005 02:12:13 +0000 : chx

Attachment: http://drupal.org/files/issues/depend_2.patch (3.15 KB)


Sun, 06 Mar 2005 04:13:14 +0000 : gordon


Not only is this something that I have wanted for filestore2 for quite
a while, but has not been on my priority list. But this would be
extremely useful for the ecommerce modules, as there seems to be alot
of interdependancy.

Also on a side note, it would also be good for a module to be able to
reject an enabling. So if the module is going to stop drupal from
running if it does have its tables created, it will inform the user and
not be turned on. This could actually be done allowing the dependancy
hook to do some checking and so stop the module from being able to be


Sun, 06 Mar 2005 08:19:09 +0000 : mathias

This would make installing the ecommerce package easier given that
modules are no longer listed alphabetically from within their
subdirectories.  The modules are scattered all over the page unless I
adopt some sort of ec_ prefix to module naming.

I wonder how Adrian's installer handles dependencies?


Sun, 06 Mar 2005 10:42:01 +0000 : adrian

My installer doesn't currently handle dependencies, and I am not
convinced this should go into 4.6.

There's more to dependency checking than just 'depends' including fun
things like circular dependencies and version checking.
Once we have versioning for drupal modules / schemas .. we can look at
this again. 

Vlado apparently has dependency checking code already built, that he is
going to donate to the installer effort.


Sun, 06 Mar 2005 10:57:54 +0000 : chx

Attachment: http://drupal.org/files/issues/depend_3.patch (3.26 KB)

Well, I know there could be problems. However, circular dependecy is
handled with my code. You have module A, this depends on B, this
depends on C which depends on A. You tick A, press Save. Next listing
will tick B instead of you, press Save. Next listing will tick C
instead of you, press Save. Next listing will be happy, 'cos A is on.

Adrian convinced me that taking a parameter is a good thing, so it's
in. And he asked for calling the hook _info. So be it. And he pointed
out that I do not understand drupal_set_message which was true. So now
the status message is now displayed only once. Shall I protect the new
error message from such a duplication?

And please, get this simple system into 4.6 'cos (as already stated)
the forum-comment dependency has threads on drupal.org already so it
could be called a bug.


Sun, 06 Mar 2005 11:08:37 +0000 : chx

Attachment: http://drupal.org/files/issues/depend_4.patch (3.27 KB)

Minor things: default hook_info key shall be called 'depends' not
'required' (Adrian). Message should be 'enabled' for consistency


Tue, 08 Mar 2005 19:56:02 +0000 : Dries

The status message needs work (incorrect use of em, confusing wording). 
Lastly, the way messages are handled and fiddled with is peculiar at
best: the logic is spread out over different functions and complicated
because of that.  I'm not happy with the code as is.


Sat, 12 Mar 2005 10:37:22 +0000 : Dries

Setting this 'active'.  Waiting for new patch.


Sun, 13 Mar 2005 20:21:21 +0000 : chx

Attachment: http://drupal.org/files/issues/depend_5.patch (3.3 KB)

Here is new version. Hope you like it more than the previous one.


Sun, 13 Mar 2005 20:29:31 +0000 : chx

One s too much...


Sun, 13 Mar 2005 20:31:17 +0000 : chx

Attachment: http://drupal.org/files/issues/depend_6.patch (3.3 KB)

grrrr... it submitted without attaching... is there some way to make
preview required for me...?


Mon, 14 Mar 2005 10:28:54 +0000 : stefan nagtegaal

chx: I do like the approach you took, but I think we should return more
information to the administrator.
You did:

  drupal_set_message(t('%module is enabled because other modules depend on it.', array ('%module' =>'<em>'. $file->name .'</em>')), 'error');

First I don't think you need to have the $type = 'error' as the second
argument.. Imo it is not an error, just a notification. Or am I wrong?

And secondly, can't we do something like:

  drupal_set_message(t("Because '%module' depends on functionality offered by '%modules', these modules are also enabled to omit possible problems.', array ('%module' => "<em>$file->name</em>", '%modules' => "<em>$required_modules</em>")));

I would really appreciate feedback of any of you...


Fri, 25 Mar 2005 23:17:35 +0000 : chx

Attachment: http://drupal.org/files/issues/dependency1.patch (2.34 KB)

Whole new dependency system! This has nothing to do the with previous
patches. Those were a bit hackish.

hook_install('depends') may return a string or an array of strings. The
modules whose name is returned, will be switched on. These new modules'
dependencies are also dealt with. And so on.

I have thought of using format_plural, but the arguments make that


Sat, 26 Mar 2005 01:46:00 +0000 : chx

Attachment: http://drupal.org/files/issues/dependency1_0.patch (2.34 KB)

A few 's are gone according to Steven's advice.


Sat, 26 Mar 2005 03:24:59 +0000 : mathias

Attachment: http://drupal.org/files/issues/dependency.patch (2.62 KB)

+1, and a slice of blueberry pie.

I tested this patch against the ecommerce package and it worked as
expected.  My attached patch simply tweaks a couple minor code details
and made the the dependency message a little easier to understand.

Please add this to 4.6.  This could be viewed as a major usability
benefit for module developers and end users ;-)


Sat, 26 Mar 2005 14:55:08 +0000 : stefan nagtegaal

Can't we refrase this:

t("The following module has been enabled since it's dependent on %module in order function properly: %dependents.", array ('%module' => '<em>'. $module .'</em>', '%dependents' => '<em>'. implode(', ', $enabled) .'</em>')

I'm not sure why, but I don't think this is userfriendly enough..
Anisa, (I'm not sur eshe is on this list) do you have a better idea?


Sat, 26 Mar 2005 20:12:52 +0000 : adrian

Two things ..
a) Enabling a module is not installing a module, so the naming of the
_install hook (wether it is already being used in my install api or
not) is wrong.
b) don't add a hook when we already have one. 

hook_info used to be used for the module description, but currently is
only being used for auth. I am rolling a patch which uses hook_info()
(as I am intending to do in my install patches).


Sat, 26 Mar 2005 22:33:32 +0000 : chx

Attachment: http://drupal.org/files/issues/dependency_0.patch (2.61 KB)

OK I changed back to hook_info. However, hook_info PHPdoc needs a


Mon, 28 Mar 2005 00:01:32 +0000 : chx

Attachment: http://drupal.org/files/issues/dependency_1.patch (2.69 KB)

I contacted Anisa who had a better wording idea. Thanks!

To quote her: "Keep in mind that to the user, this is a surprise.
 They may not have read the documentation properly, and not anything
about X.  'for you' suggests that this is a service, not a
scary-computer-doing-things-on-its-own behavior. 

I added the line about permissions and settings to remind the user that
just because X module has been enabled for them, not everything will be
exactly perfect." and she had had advice about changing "permissions"
(and maybe settings) to a link, but that's not for this patch... it is
listed in the usability group's todo for every module.


Mon, 28 Mar 2005 02:42:35 +0000 : moshe weitzman

not just permissions - some database table(s) may need manual creation.


Sun, 03 Apr 2005 19:48:04 +0000 : stefan nagtegaal

Dries, what is wrong with this patch?
I think it is a great (and not even a very big code change) improvement
to the current drupal.. It's pretty straight-forward, and makes sense in
a lot of ways..

If the patch needs more work, just let it know and i'll see what I can


Sun, 03 Apr 2005 21:25:38 +0000 : chx

Attachment: http://drupal.org/files/issues/dependency_2.patch (2.9 KB)

reword again to include moshe's suggestion. theme placeholder usage.
proper cvs diff.


Mon, 11 Apr 2005 23:27:53 +0000 : chx

Any chance for 4.6?


Tue, 12 Apr 2005 11:34:46 +0000 : menesis

Looking at the new patch, I was surprised to see how small it is...
There's much more to dependency system than that.

I don't like the approach at all. You automatically enable the required
modules and only inform the user afterwards. As I'm used in Linux
packaging tools, I expect to be asked if I really want to enable the
required module and the module itself. Those modules might not be
installed, in this case have to tell the user to download the required
modules and properly install them - create tables, enable, configure,
and then try enabling this module again. Your patch does not deal with
that and might make the system unusable, when a broken module is
automatically enabled.

A real package/dependency system should have more different
relationships - depends on, recommends, suggests, conflicts... After
you select which modules to enable, you get a listing of additional
dependant modules with checkboxes defaulting to most likely action, and
possibly disabled. Then you confirm that and selected modules are


Fri, 01 Jul 2005 18:08:12 +0000 : stefan nagtegaal

This isn't applying anymore..

Dries, what are your thoughts about the dependency system? I think it's
quite good, for the sake of usability, it surely will be!

Please share your thoughts so we can get this slippin' in...


Fri, 05 Aug 2005 18:12:09 +0000 : chx

I will reroll this when I get home. Either this or Adrian's install
system needs to get into 4.7. Maybe this system is not ideal and does
not deal with broken modules and such but you can always enable such
things by hand. So, this won't make anything worse. (And I want my pie
from matthias...)


Wed, 07 Sep 2005 04:24:48 +0000 : chx

Attachment: http://drupal.org/files/issues/dependency_3.patch (2.87 KB)



Wed, 07 Sep 2005 07:51:08 +0000 : Dries

I'll look into this later.

(The forum module depends on the taxonomy module too.  Easy enough to


Wed, 07 Sep 2005 08:05:51 +0000 : stefan nagtegaal

Setting status back to "code needs work", because:
- archive.module depends on node.module;
- blogapi.module depends on node.module and
- blog.module depends on node.module;
- book.module depends on node.module;
- forum.module depends on comment.module and taxonomy.module;
- page.module depends on node.module;
- path.module depends on node.module and
- poll.module depends on node.module;
- story.module depends on node.module;
- tracker.module depends on node.module and comment.module (?);
- upload.module depends on node.module and blog.module/forum.module
- comment.module depends on node.module (?);

Or, am I miunderstanding the point here? Looking at your code, I guess
not.. But, maybe it's me...
Please feel free to ignore my comment if useless...


Wed, 07 Sep 2005 08:37:39 +0000 : chx

The dependency system itself works nicely. That we can add more stuff to
use it -- true. That may come later. First, get the stuff in.


Wed, 07 Sep 2005 09:00:36 +0000 : chx

Attachment: http://drupal.org/files/issues/dependency_4.patch (2.88 KB)

Added taxonomy to forum_info.


Wed, 07 Sep 2005 09:13:57 +0000 : Kjartan

- Do you really need the $new_module stuff? Couldn't you just recurse at
the point were you enable the module and avoid the extra logic?
- Why arent you using format_plural() for the message?


Wed, 07 Sep 2005 09:39:11 +0000 : chx

format_plural accepts no parameters, while I have a few.

The new_module logic is good because you do not recurse for every
single module only after a bunch of them. Performance is better.


Thu, 08 Sep 2005 20:31:44 +0000 : chx

Attachment: http://drupal.org/files/issues/dependency_5.patch (4.5 KB)

format_plural? Be it. Recursion problems? Removed.

I patched format_plural so that it accepts the same args as t and
passes them over to t.


Thu, 08 Sep 2005 21:30:23 +0000 : m3avrck

+1 works great. Applies to HEAD cleanly but system.module is out of date
in the patch (off by one line but still clean). Tried out a few
different combos, all modules that should be enabled were. Works on PHP
5.0.5 with no call-by-reference issues either ;-)


Thu, 08 Sep 2005 22:47:54 +0000 : chx

Attachment: http://drupal.org/files/issues/dependency_6.patch (4.92 KB)

thehunkmonkgroup asked me that if a required module is not present then
what? He is right, absolutely right.


Sun, 11 Sep 2005 15:46:05 +0000 : Jose A Reyero

"module has been enabled for you because %module needs it to work

So, modules are enabled authomatically? Come on, what's this?, Windows'
you-stupid-user-we-know-better-what-you-need philosopy?

And what if I have a replacement module with a different name?

I think a big warning about dependencies is ok. But enforcing a
disabled module is way too much...


Sun, 18 Sep 2005 17:21:21 +0000 : Dries

Just like Jose, I'm not convinced automatically enabling modules is a
good thing.

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