[imp] Undefined class constant 'ALPHACHANNEL_REMOVE'

[Simon B]

Hi

Since a while (I haven't changed my git update script, but this
definitely started bfore your git infra changes), I've been unable to
view some/most emails with attachments - particularly PDFs.

Sometimes, (i.e. from some senders), I can reach the attachment if I
double-click and open the email.  But mostly I get this error..

A fatal error has occurred

Undefined class constant 'ALPHACHANNEL_REMOVE'

in /usr/share/git-horde5/imp/lib/Mime/Viewer/Pdf.php:136

1. Horde_ErrorHandler::catchFatalError()

Details

The full error message is logged in Horde's log file, and is shown
below only to administrators. Non-administrative users will not see
error details.

ErrorException Object
(
    [message:protected] => Undefined class constant 'ALPHACHANNEL_REMOVE'
    [string:Exception:private] =>
    [code:protected] => 0
    [file:protected] => /usr/share/git-horde5/imp/lib/Mime/Viewer/Pdf.php
    [line:protected] => 136
    [trace:Exception:private] => Array
        (
            [0] => Array
                (
                    [function] => catchFatalError
                    [class] => Horde_ErrorHandler
                    [type] => ::
                    [args] => Array
                        (
                        )

                )

        )

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

I realise updating from git would probably fix it, but until I can get
to that, I thought you should know.

Cheers.

Simon