Input file overwritten without warning if the file extension is not (\.ome)?\.tiff?

[melissalinkert]

Some TIFF-based formats such as SVS commonly use an extension other than .tiff. With current latest version via pip install generate-tiff-offsets, download https://openslide.cs.cmu.edu/download/openslide-testdata/Aperio/CMU-1.svs and place in a test directory:

$ ls -og
total 173392
-rwxrwxrwx 1 177552579 Nov  6 15:51 CMU-1.svs
$ generate_tiff_offsets --input_file CMU-1.svs
$ ls -og CMU-1.svs 
-rwxrwxrwx 1 66 Nov  6 15:54 CMU-1.svs
$ cat CMU-1.svs 
[157121040, 157593686, 175414110, 177087892, 177463730, 177551836]

The output looks correct, but I would have expected it to be placed in a separate CMU-1.svs.json file instead of overwriting the input file.

[ilan-gold]

Interesting. @melissalinkert Would you be able/willing to make a PR?