bpo-45324: Capture data in FrozenImporter.find_spec() to use in exec_module(). (gh-28633)

Before this change we end up duplicating effort and throwing away data in FrozenImporter.find_spec().  Now we do the work once in find_spec() and the only thing we do in FrozenImporter.exec_module() is turn the raw frozen data into a code object and then exec it.

We've added _imp.find_frozen(), add an arg to _imp.get_frozen_object(), and updated FrozenImporter.  We've also moved some code around to reduce duplication, get a little more consistency in outcomes, and be more efficient.

Note that this change is mostly necessary if we want to set __file__ on frozen stdlib modules. (See https://bugs.python.org/issue21736.)

https://bugs.python.org/issue45324

1 files changed, 3 insertions, 0 deletions

diff --git a/Misc/NEWS.d/next/Core and Builtins/2021-09-29-12-02-39.bpo-45324.BTQElX.rst b/Misc/NEWS.d/next/Core and Builtins/2021-09-29-12-02-39.bpo-45324.BTQElX.rst
new file mode 100644
index 0000000..7b16847
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2021-09-29-12-02-39.bpo-45324.BTQElX.rst
@@ -0,0 +1,3 @@
+In FrozenImporter.find_spec(), we now preserve the information needed in
+exec_module() to load the module.  This change mostly impacts internal
+details, rather than changing the importer's behavior.