id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
28242	Move ImageField file extension validation from models to forms for better backwards compatibility	Manatsawin Hanmongkolchai	nobody	"FileExtensionValidator was added in #21548 and is breaking existing Django application.

To reproduce:

- Create a model {{{image1 = models.ImageField(upload_to=lambda instance, filename: 'image1/{}'.format(instance.pk), blank=True)}}}. Make sure that upload_to does not contains any extension
- Create an instance of that model in Django Admin with a file uploaded.
- Try to update the just created model with no changes. It will fail with the error ""File extension '' is not allowed. Allowed extensions are: 'bmp, bufr, cur, pcx, dcx, dds, ps, eps, fit, fits, fli, flc, fpx, ftc, ftu, gbr, gif, grib, h5, hdf, png, jp2, j2k, jpc, jpf, jpx, j2c, icns, ico, im, iim, tif, tiff, jfif, jpe, jpg, jpeg, mic, mpg, mpeg, mpo, msp, palm, pcd, pdf, pxr, pbm, pgm, ppm, psd, bw, rgb, rgba, sgi, ras, tga, webp, wmf, emf, xbm, xpm'."" on the field.

This issue is not present in 1.10.7 (as #21548 is not merged yet)."	Cleanup/optimization	closed	Forms	1.11	Normal	fixed			Accepted	1	0	0	0	0	0