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
29429	Make len lookup for ArrayField use the array_length function	creative3000		"When you filter by len like in documentation example:
{{{
#!python
  Post.objects.filter(tags__len=1)
}}}

But if you try to annotate something an error pops up example:
{{{
#!python
 Post.objects.all().annotate(tag_len=F('tags__len'))
}}}
It really seems that it should work by default,  but instead I needed to use something like this 
{{{
#!python
 Post.objects.all().annotate(tag_len=Func(F('tags'), 1, function='array_length'))
}}}
"	Bug	closed	contrib.postgres	2.0	Normal	needsinfo	db orm ArrayField postgres		Accepted	0	0	0	0	0	0