flag -s does not work as expected

The help says that whith using -s the flag -o for targetfile is not needed, but doing so will prompt with the need of that flag. Using the flag with the same target as -i infile will result in a 0 byte file.

./fixit_tiff -s -p -i ~/Dropbox/geo_tiff_files/cstm/dodo.tif

fixit tiffs answer:
infile='/home/vbauer/Dropbox/geo_tiff_files/cstm/dodo.tif', outfile='(null)'
could not open file '(null)' for writing