Ping?

To further debug this issue, we need details of the IMP -> IMAP/POP 
communication.

To enable debugging, see instructions contained in 
imp/config/backends.php (the 'debug' config parameter).

Debugging should not be enabled on a production server,   Attach/post 
only the portion of the log that directly deals with the problem 
reported (it may be simplest to clear the log file and then perform 
the event that causes the error).

Related has set inline=true, yes.

Something strange is going on.  I see that message fine, without 
errors.  But a debug backtrace shows differences.

Yours:

11. Horde_Mime_Viewer_Base->render() /var/www/horde4/imp/lib/Contents.php:472
12. IMP_Mime_Viewer_Html->_renderInline()
/usr/share/php/Horde/Mime/Viewer/Base.php:156
13. IMP_Mime_Viewer_Html->_IMPrender()
/var/www/horde4/imp/lib/Mime/Viewer/Html.php:78

Mine:

11. Horde_Mime_Viewer_Base->render() /disk2/src/horde/imp/lib/Contents.php:472
12. IMP_Mime_Viewer_Related->_renderInline() 
/disk2/src/horde/framework/Mime_Vie
wer/lib/Horde/Mime/Viewer/Base.php:156
13. IMP_Mime_Viewer_Related->_IMPrender() 
/disk2/src/horde/imp/lib/Mime/Viewer/R
elated.php:58
14. IMP_Contents->renderMIMEPart() 
/disk2/src/horde/imp/lib/Mime/Viewer/Related.
php:108
15. Horde_Mime_Viewer_Base->render() /disk2/src/horde/imp/lib/Contents.php:472
16. IMP_Mime_Viewer_Html->_renderInline() 
/disk2/src/horde/framework/Mime_Viewer
/lib/Horde/Mime/Viewer/Base.php:156
17. IMP_Mime_Viewer_Html->_IMPrender() 
/disk2/src/horde/imp/lib/Mime/Viewer/Html
.php:78

The difference - there is no mention of the multipart/related handler 
in yours, which makes no sense since the alternative part lives under 
the related part and should be parsed by the code in the related part.

Does the 'related' entry in imp/config/mime_drivers.php have 'inline' 
set to true?

See attachment

Please provide the message source of a message that triggers this error.

Just added Horde::debug($related_part->getMetadata('related_cids')); 
an line before foreach is called.

It's reproducable for messages triggered by an alarming kronolith 
event with email-notification. When viewing the notification-mail the 
first time in dimp (not cached), the error is logged.


2011-04-07T15:59:54+02:00 DEBUG: Variable information:
NULL

Backtrace:
  1. Horde_Core_Ajax_Application->doAction() 
/var/www/horde4/services/ajax.php:60
  2. call_user_func() /usr/share/php/Horde/Core/Ajax/Application.php:95
  3. IMP_Ajax_Application->showPreview()
  4. IMP_Views_ShowMessage->showMessage() 
/var/www/horde4/imp/lib/Ajax/Application.php:1022
  5. IMP_Ui_Message->getInlineOutput() 
/var/www/horde4/imp/lib/Views/ShowMessage.php:269
  6. IMP_Contents->renderMIMEPart() /var/www/horde4/imp/lib/Ui/Message.php:538
  7. Horde_Mime_Viewer_Base->render() /var/www/horde4/imp/lib/Contents.php:472
  8. IMP_Mime_Viewer_Alternative->_renderInline() 
/usr/share/php/Horde/Mime/Viewer/Base.php:156
  9. IMP_Mime_Viewer_Alternative->_IMPrender() 
/var/www/horde4/imp/lib/Mime/Viewer/Alternative.php:58
10. IMP_Contents->renderMIMEPart() 
/var/www/horde4/imp/lib/Mime/Viewer/Alternative.php:141
11. Horde_Mime_Viewer_Base->render() /var/www/horde4/imp/lib/Contents.php:472
12. IMP_Mime_Viewer_Html->_renderInline() 
/usr/share/php/Horde/Mime/Viewer/Base.php:156
13. IMP_Mime_Viewer_Html->_IMPrender() 
/var/www/horde4/imp/lib/Mime/Viewer/Html.php:78
14. Horde::debug() /var/www/horde4/imp/lib/Mime/Viewer/Html.php:168

Just found this error some times in horde's log - don't know exactly 
which action it takes to reproduce. It occurred when I set some mails 
as read, but this action applyed correctly.

2011-04-06T11:13:41+02:00 WARN: HORDE [imp] PHP ERROR: Invalid 
argument supplied for foreach() [pid 19465 on line 169 of 
"/var/www/horde4/imp/lib/Mime/Viewer/Html.php"]

When this error is logged, an server-error-notification is popping up 
in frontend.