Google code search for

os.execlp\([^*,]+\) lang:python

returns 15 hits, two of which are the same as Matthias found.  I am not sure what these results mean for the issue (and Matthias does not reach a conclusion either.)

Note that the status quo in 3.x is that os.execlp(single_arg) is invalid, so all these examples will stop working in 3.x and will not be fixed by 2to3.  My patch will only make failure happen sooner and reason for it more obvious.

I am not very happy about issue1039 (r57731) to begin with.  (See my comments at issue8154.)  It was rather hastily applied 3.x feature without a corresponding -3 warning and not even a mention in the NEWS file.  However if r57731 stays as a strict POSIX compliance feature, I think it will be cleaner to enforce >1 argument to os.execl* functions in their signatures rather than in a run-time check.