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
17159	Paginator.Page() should throw an exception for invalid [next|previous]_page_number()	mehta.apurva@…	neaf	"The next_page_number() and previous_page_number() currently return an incremented or decremented number without verifying if the page is in the range or not. They should instead throw an exception.

Repro Steps
=======
{{{#!python
>>> from django.core.paginator import Paginator
>>> objects = ['john', 'paul', 'george', 'ringo', 'bill', 'gates', 'steve', 'jobs']
>>> p = Paginator(objects, 2)
>>> p.count
8
>>> p.num_pages
4
>>> p.page_range
[1, 2, 3, 4]
>>> p.page(1).has_previous()
False
>>> p.page(4).has_next()
False
>>> p.page(1).previous_page_number()  ### Should throw Exception
0   
>>> p.page(4).next_page_number() ### Should throw Exception
5
}}}"	New feature	closed	Core (Other)	1.3	Normal	fixed	paginator core		Ready for checkin	1	1	1	0	1	0