django.core.files.base.File's chunk method uses the file's size to determine how many chunks to return. Retrieving the size of a file is very fast for simple files, but may be very expensive for compressed files and other storage mechanisms. And in this case, it's completely unnecessary. Replacing the size-based loop with a simple check for the end of the stream has fewer dependencies and avoids a potentially expensive operation.

To cite one practical example, if the file is stored as a compressed file on disk, the current implementation will result in either decompressing the entire file twice or caching the entire decompressed file in memory. Removing the size dependency avoids both.

We need a design decision on this - the patch looks fine.

Also this ticket stating that the chunk size isn't always honored at #12157

+1 for removing the size() check in chunks(). It tends to break things when wrapping non-file-system file-like-objects such as StringIO()

However, that said, this patch might pose a problem for file-like-objects that should not be over-read socket connection. The patch probably should honor the file size if it exists.

See also #13901.

Change UI/UX from NULL to False.

Change Easy pickings from NULL to False.

When fixing #15644, the chunks implementation has been changed to not depend on size any more (r17871). It remains to be seen if comment:5 (over-read socket connection) might be true, triggering new bug reports. Real use-cases welcome...