Summary

Support deferred attributes in JSONField and improve Django compatibility.

Review Request #10469 — Created March 27, 2019 and submitted April 10, 2019, 4:24 p.m.

Information

Owner

chipx86

Repository

Djblets

Branch

release-2.0.x

Bugs

Depends On

Reviewers

Groups

djblets

People

Description

Other changes to the parent TextField in newer versions of Django
broke other aspects of JSONField. TextField.get_prep_value() was
added, which forced the value to be a string, and in our case this
resulted in some unwanted serialization. We now override this, instead
of get_db_prep_value() (which will, in the default implementation,
calls our new method and do the right thing).

On the other end of that process is the to_python() method, which we
weren't overriding. We now provide this, and have it return a
deserialized representation of the data.

Testing Done

Djblets and Review Board unit tests pass.

Commits

Summary	ID
Support deferred attributes in JSONField and improve Django compatibility. JSONField was prone to unwanted queries when working with models that defferred the JSONField. This wasn't so much a major problem on Django 1.6, but manifested on newer versions of Django. The core issue was that, during the model initialization phase, `JSONField` would try to load data from the model in order to normalize it, and if the field was deferred, this act would trigger a query. To fix this, this change now checks whether the attribute is deferred before performing any lookups. Other changes to the parent `TextField` in newer versions of Django broke other aspects of `JSONField`. `TextField.get_prep_value()` was added, which forced the value to be a string, and in our case this resulted in some unwanted serialization. We now override this, instead of `get_db_prep_value()` (which will, in the default implementation, calls our new method and do the right thing). On the other end of that process is the `to_python()` method, which we weren't overriding. We now provide this, and have it return a deserialized representation of the data.	676c7f21e9bd03ec3aa66c55654837a0d704714d

Summary

Support deferred attributes in JSONField and improve Django compatibility.

JSONField was prone to unwanted queries when working with models that defferred the JSONField. This wasn't so much a major problem on Django 1.6, but manifested on newer versions of Django. The core issue was that, during the model initialization phase, `JSONField` would try to load data from the model in order to normalize it, and if the field was deferred, this act would trigger a query. To fix this, this change now checks whether the attribute is deferred before performing any lookups. Other changes to the parent `TextField` in newer versions of Django broke other aspects of `JSONField`. `TextField.get_prep_value()` was added, which forced the value to be a string, and in our case this resulted in some unwanted serialization. We now override this, instead of `get_db_prep_value()` (which will, in the default implementation, calls our new method and do the right thing). On the other end of that process is the `to_python()` method, which we weren't overriding. We now provide this, and have it return a deserialized representation of the data.

676c7f21e9bd03ec3aa66c55654837a0d704714d

Issues

Description	From	Last Updated
F401 'django.db.models.query_utils.DeferredAttribute' imported but unused	reviewbot	March 27, 2019, 7:05 p.m.
F841 local variable 'site' is assigned to but never used	reviewbot	March 27, 2019, 7:05 p.m.

flake8 failed.

JSHint passed.

flake8

djblets/db/tests/test_json_field.py (Diff revision 1)
The issue has been resolved. Show all issues
```
F401 'django.db.models.query_utils.DeferredAttribute' imported but unused
```
djblets/db/tests/test_json_field.py (Diff revision 1)
The issue has been resolved. Show all issues
```
F841 local variable 'site' is assigned to but never used
```

Change Summary:

Removed an unused import and variable name.

Commits:

	Summary	ID
	Support deferred attributes in JSONField and improve Django compatibility. JSONField was prone to unwanted queries when working with models that defferred the JSONField. This wasn't so much a major problem on Django 1.6, but manifested on newer versions of Django. The core issue was that, during the model initialization phase, `JSONField` would try to load data from the model in order to normalize it, and if the field was deferred, this act would trigger a query. To fix this, this change now checks whether the attribute is deferred before performing any lookups. Other changes to the parent `TextField` in newer versions of Django broke other aspects of `JSONField`. `TextField.get_prep_value()` was added, which forced the value to be a string, and in our case this resulted in some unwanted serialization. We now override this, instead of `get_db_prep_value()` (which will, in the default implementation, calls our new method and do the right thing). On the other end of that process is the `to_python()` method, which we weren't overriding. We now provide this, and have it return a deserialized representation of the data.	a7dea5c70bc3d5fafc5a579d6d58cc85a8aaa998
	Support deferred attributes in JSONField and improve Django compatibility. JSONField was prone to unwanted queries when working with models that defferred the JSONField. This wasn't so much a major problem on Django 1.6, but manifested on newer versions of Django. The core issue was that, during the model initialization phase, `JSONField` would try to load data from the model in order to normalize it, and if the field was deferred, this act would trigger a query. To fix this, this change now checks whether the attribute is deferred before performing any lookups. Other changes to the parent `TextField` in newer versions of Django broke other aspects of `JSONField`. `TextField.get_prep_value()` was added, which forced the value to be a string, and in our case this resulted in some unwanted serialization. We now override this, instead of `get_db_prep_value()` (which will, in the default implementation, calls our new method and do the right thing). On the other end of that process is the `to_python()` method, which we weren't overriding. We now provide this, and have it return a deserialized representation of the data.	676c7f21e9bd03ec3aa66c55654837a0d704714d

Diff:

Revision 2 (+182 -24)

Show changes

	djblets/db/fields/json_field.py
	djblets/db/tests/test_json_field.py

Checks run (2 succeeded)

flake8 passed.

JSHint passed.

Ship it!

```
Ship It!
```

Status: Closed (submitted)

Change Summary:

Pushed to release-2.0.x (efd7ebe)