[Users] LiteHTML Plugin 'Hangs' When Trying to Display Certain HTML Emails

[Dustin Miller]

System: Linux Mint Debian Edition, Xfce DE, various versions of git
around and including stable release v4.2.0.

I have one or two emails with text/html message parts that the
LiteHtml plugin takes an abnormally long time to display, along with
causing higher CPU usage. This problem also makes Claws unusable until
the email displays.

With one problem email, if I wait about a minute or less, it will
eventually display. The related debug output for this one is here:
https://controlc.com/86035358 . (I can also forward this email to a
developer if desired.) I also have one email that takes so long that I
finally just force Claws to close. (I also saved the debug output for
this one, although it looks pretty similar to the other one, so I
didn't paste it online. I won't be able to forward this email for
testing.)

The display time is fine / normal with no HTML viewer, Fancy, or Dillo.
I'm not interested in using Fancy or Dillo because of Bug 4516. I've
also noticed that, with the latest LiteHTML changes, it seems to be
doing a lot better at rendering emails, which means less need to use an
external browser for viewing.

I've confirmed that the problem exists in v4.2.0git6, v4.2.0, and
v4.1.1git versions 101-102. I was unable to successfully build
v4.1.1git versions 93-97 and 100 (didn't bother trying with 98-99)
becaues of 'make' errors related to LiteHTML (not sure if this was user
error or to be expected).

The problem does not exist for v4.1.1git92 (c556ff93f) (“URIs may
contain the '$' dollar sign (fix broken syntax).”). So I'm guessing
it's related to one or more of the LiteHTML-related changes leading up
to and including v4.1.1git102.

Probably the next thing to figure out is whether it's a Claws issue or
an upstream issue. Any thoughts on that?

If other users have ideas about how to do more / better debugging on
this, feel free to chime in.

If developers would like me to do more specific testing, provide more
information, forward a sample problem email, attempt debugging with gdb,
etc., let me know.

Thanks,
Dustin