Thanks! Working fine with uninstalled Horde_Service_Weather package.

Changes have been made in Git (master):

commit 4e3d657bf4ce82abb16d7b4104c9aca6eb703ba0
Author: Michael J Rubinsky <mrubinsk@horde.org>
Date:   Fri Dec 2 15:14:36 2016 -0500

     Bug: 14527 Disable Metar block if Horde_Service_Weather not present.

  horde/lib/Block/Metar.php | 4 ++++
  1 file changed, 4 insertions(+)

http://github.com/horde/horde/commit/4e3d657bf4ce82abb16d7b4104c9aca6eb703ba0

Ahhhh. The static blocks configuration pulls the list of available 
blocks. Thanks for the trace.

Easy fix, just need to add a check for the existence of the class in 
the block - which should have been there to begin with anyway.

Will take care of it, thanks for the report.

Backtrace:

1. Horde_Config_Form->__construct() 
/datastore/dev/share/pear/www/horde/admin/config/config.php:35
  2. Horde_Config->readXMLConfig() 
/datastore/dev/share/pear/Horde/Config/Form.php:58
  3. Horde_Config->_parseLevel() /datastore/dev/share/pear/Horde/Config.php:204
  4. Horde_Config->_parseLevel() /datastore/dev/share/pear/Horde/Config.php:725
  5. Horde_Config->_parseLevel() /datastore/dev/share/pear/Horde/Config.php:712
  6. Horde_Config->_getEnumValues() 
/datastore/dev/share/pear/Horde/Config.php:602
  7. Horde_Config->_handleSpecials() 
/datastore/dev/share/pear/Horde/Config.php:1790
  8. Horde_Registry->callAppMethod() 
/datastore/dev/share/pear/Horde/Config.php:1861
  9. call_user_func_array() /datastore/dev/share/pear/Horde/Registry.php:1196
10. Horde_Application->configSpecialValues()
11. Horde_Core_Block_Collection->getBlocksList() 
/datastore/dev/share/pear/www/horde/lib/Application.php:122
12. Horde_Core_Block_Collection->_loadBlocks() 
/datastore/dev/share/pear/Horde/Core/Block/Collection.php:159
13. Horde_Block_Metar->__construct() 
/datastore/dev/share/pear/Horde/Core/Block/Collection.php:500
  [pid 25045 on line 28 of 
"/datastore/dev/share/pear/www/horde/lib/Block/Metar.php"]
2016-12-01T16:13:27+01:00 EMERG: HORDE [horde] Class 
'Horde_Service_Weather_Metar' not found [pid 25045 on line 38 of 
"/datastore/dev/share/pear/www/horde/lib/Block/Metar.php"]


I'll just install the package for now ;)

Yeah, it shouldn't be required. There are other blocks that also use 
other classes from this same package, so whatever it is, it's specific 
to the Metar code.
I'll be able to look at this more closely tomorrow if needed.

it's in the "optional" section and therefore not installed on my box.

I'll do a stack trace next.

I guess the question is what is horde block code doing running from 
the config screen. I can't think of anywhere that would done. Can you 
get a stack trace of where this is being called?

Also, the Horde package.xml already has a dependency on 2.4.0 of 
Horde_Service_Weather, which is the version that introduced the Metar 
class.

When trying to access the config module to upgrade the 'horde' base config,
horde crashes for me. We should either fix the code or specify
a dependency on Horde_Service_Weather_Metar in package.xml of the 'horde' app.

Class 'Horde_Service_Weather_Metar' not found

1. Horde_ErrorHandler::catchFatalError()

ErrorException Object
(
     [message:protected] => Class 'Horde_Service_Weather_Metar' not found
     [string:Exception:private] =>
     [code:protected] => 0
     [file:protected] => 
/datastore/dev/share/pear/www/horde/lib/Block/Metar.php
     [line:protected] => 36
     [trace:Exception:private] => Array
         (
             [0] => Array
                 (
                     [function] => catchFatalError
                     [class] => Horde_ErrorHandler
                     [type] => ::
                     [args] => Array
                         (
                         )

                 )

         )

     [previous:Exception:private] =>
     [severity:protected] => 1
     [logged] => 1
)