After commenting out the one line in my (/usr/share/doc/devilspie/README-suggested test) script, devilspie gets an assertion failure when reading it.

jani@saegusa:~$ cat .devilspie/test.ds
;(debug)
jani@saegusa:~$ devilspie
got eof

** (devilspie:7126): CRITICAL **: e_sexp_eval: assertion `f->tree != NULL’ failed

** (devilspie:7126): CRITICAL **: e_sexp_eval: assertion `f->tree != NULL’ failed

** (devilspie:7126): CRITICAL **: e_sexp_eval: assertion `f->tree != NULL’ failed

** (devilspie:7126): CRITICAL **: e_sexp_eval: assertion `f->tree != NULL’ failed

** (devilspie:7126): CRITICAL **: e_sexp_eval: assertion `f->tree != NULL’ failed

** (devilspie:7126): CRITICAL **: e_sexp_eval: assertion `f->tree != NULL’ failed

** (devilspie:7126): CRITICAL **: e_sexp_eval: assertion `f->tree != NULL’ failed

** (devilspie:7126): CRITICAL **: e_sexp_eval: assertion `f->tree != NULL’ failed

** (devilspie:7126): CRITICAL **: e_sexp_eval: assertion `f->tree != NULL’ failed

According to Debian’s bug report [1] on the issue, this occurs for all semantically empty scripts.

*[1] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=412042