"Validation failed" for addons without long description

[BenWiederhake]

How to reproduce: Use the example file for addons and remove zero-width spaces at the start of each line (snafu of a different project), yielding:

<?xml version="1.0" encoding="UTF-8"?>
<component type="addon">
  <id>gedit-code-assistance</id>
  <extends>gedit.desktop</extends>
  <name>Code Assistance</name>
  <summary>Code assistance for C, C++ and Objective-C</summary>
  <url type="homepage">http://projects.gnome.org/gedit</url>
  <metadata_license>CC0-1.0</metadata_license>
  <project_license>GPL-3.0+</project_license>
</component>

Then, try to validate the file.

Expected behavior: reference implementation validator and example in documentation agree on what is considered "correct", and the file passes validation.

Actual behavior (where ./appstreamcli is freshly built from master):

$ appstreamcli --version
AppStream-CLI-Werkzeugversion: 0.9.0
$ appstreamcli validate /tmp/as.xml 
Validierung fehlgeschlagen.
$ ./appstreamcli --version
AppStream-CLI-Werkzeugversion: 0.9.2
$ ./appstreamcli validate /tmp/as.xml 
E - as.xml:gedit-code-assistance
    The component is missing a long description. Components of this type must have a long description.

Validierung fehlgeschlagen.

So, who is right? The documentation clearly doesn't mention description as required:

For a component of type addon, the following tags are required and must be present: <id/>, <name/>, <summary/>, <metadata_license/>, <extends/>. 

EDIT: This isn't add-on specific. The "example for a very basic component" doesn't have a description, either.

EDIT 2: Tested 0.9.1 on a different system

$ appstreamcli --version
AppStream-CLI-Werkzeugversion: 0.9.1
$ appstreamcli validate --pedantic telegram-purple.metainfo.xml 
Validierung fehlgeschlagen.

[ximion]

appstreamcli is the reference validator, and usually correct - except in this case, in this case the specification is right :D - the description should be available for addons, but it's no hard requirement (although right now I wonder if it should be...)

[BenWiederhake]

It shouldn't.

In our case, we have:

<id>telegram-purple</id>
<summary>A plugin that adds support for Telegram</summary>

And that's all there is to say in this case. I'm sure that there are many more plugins that "only" add very little, and therefore can be exhaustively described in a single sentence.

Of course it's a wholly different thing when you talk about applications. These should always have long descriptions, in my eyes.

[ximion]

The description wouldn't have to be very long, it could probably just be something like:

<description>
  <p>
    Enhance Telepathy client applications with support for the Telegram mobile instant messenger.
    This plugin supports the following features: ....
  </p>
</description>

But I agree, for most plugins this doesn't make much sense, and it's likely best to not force people to write descriptions just for their own sake.