Misleading deprecation warnings raised by the cache_page decorator

[Zbigniew Siciarz]

The cache_page decorator should be called in The One True Way, which is:

@cache_page(120)
def my_view(request):
    # ...

Any old-style calls raise now a PendingDeprecationWarning. However, the warning that is printed to the stdout is misleading with regard to line numbers. All the warnings point to the warnings.warn call. It would be more useful to point to the actual @cache_page calls.

For the record, this is the current behaviour:

C:\Users\USER\v\django14\django\django\views\decorators\cache.py:47: PendingDeprecationWarning: The cache_page decorator must be called like: cache_page(timeout, [cache=cache name], [key_prefix=key prefix]). All other ways are deprecated.
  PendingDeprecationWarning)
C:\Users\USER\v\django14\django\django\views\decorators\cache.py:47: PendingDeprecationWarning: The cache_page decorator must be called like: cache_page(timeout, [cache=cache name], [key_prefix=key prefix]). All other ways are deprecated.
  PendingDeprecationWarning)
C:\Users\USER\v\django14\django\django\views\decorators\cache.py:47: PendingDeprecationWarning: The cache_page decorator must be called like: cache_page(timeout, [cache=cache name], [key_prefix=key prefix]). All other ways are deprecated.
  PendingDeprecationWarning)
C:\Users\USER\v\django14\django\django\views\decorators\cache.py:47: PendingDeprecationWarning: The cache_page decorator must be called like: cache_page(timeout, [cache=cache name], [key_prefix=key prefix]). All other ways are deprecated.
  PendingDeprecationWarning)

[Zbigniew Siciarz]

Setting correct stacklevel on the warnings.warn call.

[Zbigniew Siciarz]

With the patch applied:

C:\Users\USER\v\django14\django\tests\regressiontests\decorators\tests.py:133: PendingDeprecationWarning: The cache_page decorator must be called like: cache_page(timeout, [cache=cache name], [key_prefix=key prefix]).All other ways are deprecated.
  my_view_cached = cache_page(my_view, 123)
C:\Users\USER\v\django14\django\tests\regressiontests\decorators\tests.py:135: PendingDeprecationWarning: The cache_page decorator must be called like: cache_page(timeout, [cache=cache name], [key_prefix=key prefix]). All other ways are deprecated.
  my_view_cached2 = cache_page(my_view, 123, key_prefix="test")
C:\Users\USER\v\django14\django\tests\regressiontests\decorators\tests.py:137: PendingDeprecationWarning: The cache_page decorator must be called like: cache_page(timeout, [cache=cache name], [key_prefix=key prefix]). All other ways are deprecated.
  my_view_cached3 = cache_page(my_view)
C:\Users\USER\v\django14\django\tests\regressiontests\decorators\tests.py:139: PendingDeprecationWarning: The cache_page decorator must be called like: cache_page(timeout, [cache=cache name], [key_prefix=key prefix]). All other ways are deprecated.
  my_view_cached4 = cache_page()(my_view)

[Jannis Leidel]

In [17484]:

Fixed #17643 -- Set a better stack level for the cache_page decorator deprecation warnings. Thanks, zsiciarz.