[6.0.x] Fixed #36712 -- Evaluated type annotations lazily in template tag registration.

Ideally, this will be reverted when an upstream solution is available for
https://github.com/python/cpython/issues/141560.

Thanks Patrick Rauscher for the report and Augusto Pontes for the
first iteration and test.

Backport of 34186e731ca20a2344b1f88fd543a854d6b13a00 from main.

2 files changed, 34 insertions, 29 deletions

diff --git a/django/template/base.py b/django/template/base.py
index 5e541c3960..d6595e38e7 100644
--- a/django/template/base.py
+++ b/django/template/base.py
@@ -60,6 +60,7 @@ from django.template.context import BaseContext
 from django.utils.deprecation import django_file_prefixes
 from django.utils.formats import localize
 from django.utils.html import conditional_escape
+from django.utils.inspect import lazy_annotations
 from django.utils.regex_helper import _lazy_re_compile
 from django.utils.safestring import SafeData, SafeString, mark_safe
 from django.utils.text import get_text_list, smart_split, unescape_string_literal
@@ -825,7 +826,8 @@ class FilterExpression:
         # Check to see if a decorator is providing the real function.
         func = inspect.unwrap(func)
 
-        args, _, _, defaults, _, _, _ = inspect.getfullargspec(func)
+        with lazy_annotations():
+            args, _, _, defaults, _, _, _ = inspect.getfullargspec(func)
         alen = len(args)
         dlen = len(defaults or [])
         # Not enough OR Too many
diff --git a/django/template/library.py b/django/template/library.py
index 3fc4c5ebfc..27af7a6969 100644
--- a/django/template/library.py
+++ b/django/template/library.py
@@ -4,6 +4,7 @@ from importlib import import_module
 from inspect import getfullargspec, unwrap
 
 from django.utils.html import conditional_escape
+from django.utils.inspect import lazy_annotations
 
 from .base import Node, Template, token_kwargs
 from .exceptions import TemplateSyntaxError
@@ -110,15 +111,16 @@ class Library:
         """
 
         def dec(func):
-            (
-                params,
-                varargs,
-                varkw,
-                defaults,
-                kwonly,
-                kwonly_defaults,
-                _,
-            ) = getfullargspec(unwrap(func))
+            with lazy_annotations():
+                (
+                    params,
+                    varargs,
+                    varkw,
+                    defaults,
+                    kwonly,
+                    kwonly_defaults,
+                    _,
+                ) = getfullargspec(unwrap(func))
             function_name = name or func.__name__
 
             @wraps(func)
@@ -165,16 +167,16 @@ class Library:
 
         def dec(func):
             nonlocal end_name
-
-            (
-                params,
-                varargs,
-                varkw,
-                defaults,
-                kwonly,
-                kwonly_defaults,
-                _,
-            ) = getfullargspec(unwrap(func))
+            with lazy_annotations():
+                (
+                    params,
+                    varargs,
+                    varkw,
+                    defaults,
+                    kwonly,
+                    kwonly_defaults,
+                    _,
+                ) = getfullargspec(unwrap(func))
             function_name = name or func.__name__
 
             if end_name is None:
@@ -249,15 +251,16 @@ class Library:
         """
 
         def dec(func):
-            (
-                params,
-                varargs,
-                varkw,
-                defaults,
-                kwonly,
-                kwonly_defaults,
-                _,
-            ) = getfullargspec(unwrap(func))
+            with lazy_annotations():
+                (
+                    params,
+                    varargs,
+                    varkw,
+                    defaults,
+                    kwonly,
+                    kwonly_defaults,
+                    _,
+                ) = getfullargspec(unwrap(func))
             function_name = name or func.__name__
 
             @wraps(func)