Use maxsize=None for more LRU-caches

Not only is the implementation faster and simpler, but in cases where the functions take arguments, there's a slight chance of having fewer cache misses.

wagtail/blocks/base.py

@@ -614,7 +614,7 @@ class BlockField(forms.Field):
         )
 
 
-@lru_cache(maxsize=1)
+@lru_cache(maxsize=None)
 def get_help_icon():
     return render_to_string(
         "wagtailadmin/shared/icon.html", {"name": "help", "classname": "default"}

wagtail/contrib/settings/views.py

@@ -35,7 +35,7 @@ def get_model_from_url_params(app_name, model_name):
     return model
 
 
-@lru_cache
+@lru_cache(maxsize=None)
 def get_setting_edit_handler(model):
     if hasattr(model, "edit_handler"):
         edit_handler = model.edit_handler

wagtail/coreutils.py

@@ -256,7 +256,7 @@ def find_available_slug(parent, requested_slug, ignore_page_id=None):
     return slug
 
 
-@functools.lru_cache
+@functools.lru_cache(maxsize=None)
 def get_content_languages():
     """
     Cache of settings.WAGTAIL_CONTENT_LANGUAGES in a dictionary for easy lookups by key.

wagtail/images/checks.py

@@ -5,7 +5,7 @@ from django.core.checks import Warning, register
 from willow.image import Image
 
 
-@lru_cache
+@lru_cache(maxsize=None)
 def has_jpeg_support():
     wagtail_jpg = os.path.join(os.path.dirname(__file__), "check_files", "wagtail.jpg")
     succeeded = True
@@ -19,7 +19,7 @@ def has_jpeg_support():
     return succeeded
 
 
-@lru_cache
+@lru_cache(maxsize=None)
 def has_png_support():
     wagtail_png = os.path.join(os.path.dirname(__file__), "check_files", "wagtail.png")
     succeeded = True

wagtail/rich_text/__init__.py

@@ -19,7 +19,7 @@ features = FeatureRegistry()
 # with the feature registry
 
 
-@lru_cache(maxsize=1)
+@lru_cache(maxsize=None)
 def get_rewriter():
     embed_rules = features.get_embed_types()
     link_rules = features.get_link_types()