Changing from a tuple of the loader ID and template name to a weakref
to the loader and the template name should avoid situations whereby
the loader has changed, yet the cached templates are returned. This
would occur if the id of the new loader matches the old. A weakref is
preferred over a direct reference so that the loader can be garbaged
collected.
In 6671b973e6 the load_template method
was altered to use a cache key other than the template name. The key
chosen was the abs path as returned from the loader get_source
method. Unless there is no path in which case the name is
used. Unfortunately this introduced a performance regression, #485, as
the get_source method (in the FileStoreLoader) loads the template
(causing IO).
The purpose of #332 was to allow the loader to change whilst ensuring
the correct template was loaded, i.e. to fix this case
env.loader = loader1
env.get_template('index.html') # return loader1/index.html
env.loader = loader2
env.get_template('index.html') # also return loader1/index.html because of cache
This commit changes the cache key to be a tuple of the id(loader) and
the template name. Therefore fixing the above case without calling the
get_source method and thereby avoiding the IO load.
A test has been added to ensure the above case works as expected, this
required a minor refactor of the caching tests.
