From c2141c776b650270a7d182672c109928e007301e 2024-09-08 19:40:34
From: Lance Edgar <lance@edbob.org>
Date: 2024-09-08 19:40:34
Subject: [PATCH] docs: update comment for startup versioning workaround

now that i know a *little* more about why it is needed

---

diff --git a/rattail/config.py b/rattail/config.py
index 3db51d9b397473b9ec57931464df968744f12cd7..1a625cb7963a95f759d7a770dea60cbab015e1e6 100644
--- a/rattail/config.py
+++ b/rattail/config.py
@@ -779,11 +779,11 @@ def make_config(
         from rattail.db.config import configure_versioning
         configure_versioning(config)
 
-        # TODO: holy crap why is this needed?  without it, the first time
-        # a trainwreck query happens, InvalidRequestError is raised.  but
-        # this is clearly a trainwreck query, and yet no error if we do it
-        # this early in the startup sequence?!  i have no idea what is
-        # going on here but at least this "works" - fingers crossed..
+        # must import all sqlalchemy models before things get rolling,
+        # otherwise can have errors about continuum TransactionMeta
+        # class not yet mapped, when relevant pages are first requested
+        # cf. https://docs.pylonsproject.org/projects/pyramid_cookbook/en/latest/database/sqlalchemy.html#importing-all-sqlalchemy-models
+        # hat tip to https://stackoverflow.com/a/59241485
         if getattr(config, 'trainwreck_engines', None):
             app = config.get_app()
             trainwreck = app.get_trainwreck_handler()