bpo-42202: Store func annotations as a tuple (GH-23316)

Reduce memory footprint and improve performance of loading modules having many func annotations.

  >>> sys.getsizeof({"a":"int","b":"int","return":"int"})
  232
  >>> sys.getsizeof(("a","int","b","int","return","int"))
  88

The tuple is converted into dict on the fly when `func.__annotations__` is accessed first.

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
Co-authored-by: Inada Naoki <songofacandy@gmail.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/Doc/whatsnew/3.10.rst b/Doc/whatsnew/3.10.rst
index c5efaaa504..704de8156f 100644
--- a/Doc/whatsnew/3.10.rst
+++ b/Doc/whatsnew/3.10.rst
@@ -388,6 +388,11 @@ Optimizations
   for more details. (Contributed by Victor Stinner and Pablo Galindo in
   :issue:`38980`)
 
+* Function parameters and their annotations are no longer computed at runtime,
+  but rather at compilation time.  They are stored as a tuple of strings at the
+  bytecode level.  It is now around 100% faster to create a function with parameter
+  annotations.  (Contributed by Yurii Karabas and Inada Naoki in :issue:`42202`)
+
 Deprecated
 ==========
 
@@ -461,6 +466,12 @@ Changes in the Python API
   have been renamed to *exc*.
   (Contributed by Zackery Spytz and Matthias Bussonnier in :issue:`26389`.)
 
+CPython bytecode changes
+========================
+
+* The ``MAKE_FUNCTION`` instruction accepts tuple of strings as annotations
+  instead of dictionary.
+  (Contributed by Yurii Karabas and Inada Naoki in :issue:`42202`)
 
 Build Changes
 =============