Comment 20 for bug 958987

I've done some more exploring. The problem is caused by the function make-temp-name, called at line 7243 in r927.

Run as in experiment 2 above, make-temp-name returns "c:/python27/Scripts/ipython.bat8616nTl", which is assigned to the variable temp.

In the next line, line 7244,

(expand-file-name temp py-temp-directory)

is executed with py-temp-directory correctly set to "c:/temp", and returns "c:/python27/Scripts/ipython.bat8616nTl".

That's where the problem occurs. I suspect the problem would go away if make-temp-name just stripped out all the ":" and "/" characters in the shell name (or replaced them with "!" characters, say).