* Moved dimension field update logic out of `ImageFileDescriptor.__set__` and into its own method on `ImageField`.
* New `ImageField.update_dimension_fields` method is attached to model instance's `post_init` signal so that:
* Dimension fields are set when defined before the ImageField.
* Dimension fields are set when the field is assigned in the model constructor (fixes #11196), but only if the dimension fields don't already have values, so we avoid updating the dimensions every time an object is loaded from the database (fixes #11084).
* Clear dimension fields when the ImageField is set to None, which also causes dimension fields to be cleared when `ImageFieldFile.delete()` is used.
* Added many more tests for ImageField that test edge cases we weren't testing before, and moved the ImageField tests out of `file_storage` and into their own module within `model_fields`.
git-svn-id: http://code.djangoproject.com/svn/django/trunk@10858 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This bug actually exposed a related handful of inconsistancies in the underlying file handling and wraping, so a few related changes are in here as well:
* Dimensions are also now calculated the moment the image is assigned to the field instead of upon save.
* The base `File` object now when possible delegates its closed attribute down to the os-level file it wrapps.
* In-memory files' `close()` now is a no-op. Without this certain APIs that should be able to handle in-memory files were failing.
* Accessing `FieldFile.closed` used to open the file. That's silly, and it doesn't any more.
* Some over-eager error handling was squishing some errors that would normally be raised. One unit test was incorrectly depending on this behavior, so the test was removed.
Thanks to Armin Ronacher for much of this work.
git-svn-id: http://code.djangoproject.com/svn/django/trunk@10737 bcc190cf-cafb-0310-a4f2-bffc1f526a37
