When using Graphite 2 by Harfbuzz by Claws Mail, malloc() reports a memory corruption in some circumstances.
To produce the error,
Use Claws mail to view in the preview pane the mail attached to this report. The e-mail is a test case.
If the User Agent field is shortened to
User Agent: Mozilla
then the bug no longer occurs.
The error happens only when Harfbuzz is compiled with Graphite.
Monospace fonts were tested: Liberation Mono, Deja Vu Mono Book.
Multiple versions of Claws and Harfbuzz were tested, including the versions of software:
Claws 3.9.2
Harfbuzz 0.9.25
Graphite2 1.2.4
The software platform used was Debian unstable/sid.
Both distribution provided packages and compilations done by myself were tested of all 3 listed packages.
I very much doubt that it's Graphite that is to blame here. I don't see mention of any Graphite capable fonts; changing user agent masks things. We also haven't seen any memory corruption bugs in a looong time in Graphite. So Graphite doesn't seem to be doing anything let alone corrupting anything. About the closest I could imagine there being problems is in the harfbuzz code that integrates Graphite.
Of course, if you can pin this on Graphite, we would love to fix it and fix it fast!
(PS I'm a claws-mail user back, on Ubuntu 12.04, cm 3.8.0, so I'll get to deal with this for real when I upgrade hopefully in the new year).
I listed the wrong typeface as being used.
The typeface used was Gentium.
However, I can no longer reproduce the bug, even with rebuilding claws, harfbuzz, and graphite2.
Maybe the bug was not in any of those.
I would mark this report closed.