setup: disable install button for currently unavailable apps

- Fixes #1229.

Signed-off-by: Johannes Keyser <johanneskeyser@posteo.de>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

plinth/setup.py

@@ -143,6 +143,8 @@ class Helper(object):
             return 'up-to-date'
 
         if not current_version:
+            if any(self.list_unavailable_packages()):
+                return 'unavailable'
             return 'needs-setup'
         else:
             return 'needs-update'
@@ -166,6 +168,14 @@ class Helper(object):
             'setup_version': version
         })
 
+    def list_unavailable_packages(self):
+        """List the unavailable packages managed by the module (if any)."""
+        cache = apt.Cache()
+        managed_pkgs = getattr(self.module, 'managed_packages', [])
+        unavailable_pkgs = [pkg_name for pkg_name in managed_pkgs
+                            if pkg_name not in cache]
+        return unavailable_pkgs
+
 
 def init(module_name, module):
     """Create a setup helper for a module for later use."""

plinth/templates/setup.html

@@ -72,13 +72,22 @@
             Please wait for a few moments before trying again.
           {% endblocktrans %}
         </div>
+      {% elif setup_helper.get_state == 'unavailable' %}
+        <div class="alert alert-warning" role="alert">
+          {% blocktrans trimmed %}
+            This application is currently unavailable in your distribution.
+         {% endblocktrans %}
+        </div>
       {% endif %}
+
       <input type="submit" class="btn btn-md btn-primary"
              {{ package_manager_is_busy|yesno:'disabled="disabled"' }}
              {% if setup_helper.get_state == 'needs-setup' %}
              value="{% trans "Install" %}"
              {% elif setup_helper.get_state == 'needs-upgrade' %}
              value="{% trans "Update" %}"
+             {% elif setup_helper.get_state == 'unavailable' %}
+             value="{% trans "Install" %}" disabled="disabled"
              {% endif %} />
 
     </form>