select_related(depth=1) selects one level more than it should

[moep]

Hi,

select_related(depth=1) does select one level more than it
should.

The problem is that django.db.models.query.fill_table_cache has cur_depth=0
by default and checks if max_depth and max_depth > cur_depth. That means that
max_depth has to catch up to cur_depth one round, before it works as expected.

Changing cur_depth to 1 or checking max_depth >= cur_depth would solve
the problem but i don't know whether it introduces any other problems.

Regards

class Foo(models.Model):

bar = models.ForeignKey(Bar)

class Bar(models.Model):

foo_bar = models.ForeignKey(FooBar)

class Foobar(models.Model):

pass

---

Foo.objetcs.select_related(depth=1)
from django.db import connection
print connection.queries[-1]sql

.... FROM foo, bar, foobar ....

---

Foo.objetcs.select_related(depth=1)
from django.db import connection
print connection.queries[-1]sql

.... FROM foo, bar ....

[moep]

Forgot that we have a wiki here

file foo.py

class Foo(models.Model):
	bar = models.ForeignKey(Bar)

class Bar(models.Model):
	foo_bar = models.ForeignKey(FooBar)

class Foobar(models.Model):
	pass

with cur_depth=0
$ from foo import Foo
$ Foo.objetcs.select_related(depth=1)
$ from django.db import connection
$ print connection.queries[-1]['sql']
>>> .... FROM foo, bar, foobar ....

with cur_depth=1 or max_depth >= cur_depth
$ from foo import Foo
$ Foo.objetcs.select_related(depth=1)
$ from django.db import connection
$ print connection.queries[-1]['sql']
>>> .... FROM foo, bar ....

[Malcolm Tredinnick]

Dupe of #6018, amongst many others.