Comment 22 for bug 678421

I made a try.

As regards a syntax error, it currently results in an interrupted login, while other types of errors are silently ignored.

With my new merge proposal, a zenity/kdialog dialog is shown for all types of errors in ~/.profile and friends, and the login is completed (with a deficient configuration). They are also printed to ~/.xsession-errors.

Please feel free to test it by installing lightdm from my PPA at
https://launchpad.net/~gunnarhj/+archive/ubuntu/misc