From a0a3840094f768a47064f43c5ed2acc5b02602bb Mon Sep 17 00:00:00 2001
From: Adam Hopkins <adam@amhopkins.com>
Date: Wed, 15 Dec 2021 01:07:42 +0200
Subject: [PATCH] Add pre-registry

---
 sanic/app.py        |  9 ++++++++-
 sanic/blueprints.py | 23 +++++++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/sanic/app.py b/sanic/app.py
index 6a287471..b070a1e9 100644
--- a/sanic/app.py
+++ b/sanic/app.py
@@ -50,7 +50,7 @@ from sanic_routing.exceptions import (  # type: ignore
 )
 from sanic_routing.route import Route  # type: ignore
 
-from sanic import reloader_helpers
+from sanic import blueprint_group, reloader_helpers
 from sanic.application.logo import get_logo
 from sanic.application.motd import MOTD
 from sanic.application.state import ApplicationState, Mode
@@ -536,6 +536,12 @@ class Sanic(BaseSanic, metaclass=TouchUpMeta):
             blueprint.strict_slashes = self.strict_slashes
         blueprint.register(self, options)
 
+    def _register_lazy_blueprints(self):
+        for name, reg_info in Blueprint.__pre_registry__.items():
+            blueprint = reg_info.pop("bp")
+            if name == self.name and blueprint.name not in self.blueprints:
+                self.blueprint(blueprint, **reg_info)
+
     def url_for(self, view_name: str, **kwargs):
         """Build a URL based on a view name and the values provided.
 
@@ -1697,6 +1703,7 @@ class Sanic(BaseSanic, metaclass=TouchUpMeta):
 
     async def _startup(self):
         self._future_registry.clear()
+        self._register_lazy_blueprints()
         self.signalize()
         self.finalize()
         ErrorHandler.finalize(
diff --git a/sanic/blueprints.py b/sanic/blueprints.py
index 6a6c2e82..d4e34724 100644
--- a/sanic/blueprints.py
+++ b/sanic/blueprints.py
@@ -107,6 +107,7 @@ class Blueprint(BaseSanic):
         "version_prefix",
         "websocket_routes",
     )
+    __pre_registry__: Dict[str, Any] = {}
 
     def __init__(
         self,
@@ -461,3 +462,25 @@ class Blueprint(BaseSanic):
     ):
         for app in apps:
             app._future_registry.update(set((bp, item) for item in futures))
+
+    def pre_register(
+        self,
+        name: str = None,
+        url_prefix: Optional[str] = None,
+        host: Optional[Union[List[str], str]] = None,
+        version: Optional[Union[int, str, float]] = None,
+        strict_slashes: Optional[bool] = None,
+        version_prefix: Union[str, Default] = _default,
+    ) -> None:
+        self.__class__.__pre_registry__[name] = {
+            k: v
+            for k, v in {
+                "bp": self,
+                "url_prefix": url_prefix,
+                "host": host,
+                "version": version,
+                "strict_slashes": strict_slashes,
+                "version_prefix": version_prefix,
+            }.items()
+            if v is not None and v is not _default
+        }