(un)set with --overwrite can do better than shutil.copyfile

[edswangren]

It seems to me, anyway.

from commands.py:538 tiff_set

if os.path.realpath(source) == os.path.realpath(output) and source != '-':
    with tempfile.TemporaryDirectory('tifftools') as tmpdir:
        output = os.path.join(tmpdir, 'output.tiff')
        _tiff_set(source, output, setlist, unset, setfrom, **kwargs)
        with open(source, 'r+b') as fdest, open(output, 'rb') as fsrc:
           fdest.truncate(0)
            shutil.copyfileobj(fsrc, fdest)

I lost a file just now sending an interrupt during shutil.copyfileobj. os.replace or even shutil.move are safer and more efficient alternatives.

[manthey]

replace and move both replace the existing file. We are using copyfileobj to modify the existing file (sometimes this is important). They have different ramifications. Without a flag, we don't know which is more desirable.

Probably the safer thing to do would be to copy the original file to <src>.tmp or something similar, do the truncate and copyfileobj, and then unlink the copy. In that instance, we could also catch and reraise any exception -- but would we then try to put the original contents back in the same source or accept that we produced a new file?