Still making little progress fixing my stray engine problem.

crudkit/integrations/flask.py

@@ -1,20 +1,58 @@
+# crudkit/integrations/flask.py
 from __future__ import annotations
 from flask import Flask
-from sqlalchemy.orm import scoped_session
+from sqlalchemy.orm import scoped_session, sessionmaker
 from ..engines import CRUDKitRuntime
 from ..config import Config
 
-def init_app(app: Flask, *, runtime: CRUDKitRuntime | None = None, config: type[Config] | None == None):
+def init_app(app: Flask, *, runtime: CRUDKitRuntime | None = None, config: type[Config] | None = None):
     """
-    Initializes CRUDKit for a Flask app. Provies `app.extensions['crudkit']`
+    Initializes CRUDKit for a Flask app. Provides `app.extensions['crudkit']`
     with a runtime (engine + session_factory). Caller manages session lifecycle.
     """
     runtime = runtime or CRUDKitRuntime(config=config)
     app.extensions.setdefault("crudkit", {})
     app.extensions["crudkit"]["runtime"] = runtime
 
-    Session = runtime.session_factory
-    if Session is not None:
-        app.extensions["crudkit"]["Session"] = scoped_session(Session)
+    # Build ONE sessionmaker bound to the ONE true engine object
+    # so engine id == sessionmaker.bind id, always.
+    engine = runtime.engine
+    SessionFactory = runtime.session_factory or sessionmaker(bind=engine, **runtime._config.session_kwargs())
+    app.extensions["crudkit"]["SessionFactory"] = SessionFactory
+    app.extensions["crudkit"]["Session"] = scoped_session(SessionFactory)
+
+    # Attach pool listeners to the *same* engine the SessionFactory is bound to.
+    # Don’t guess. Don’t hope. Inspect.
+    try:
+        bound_engine = getattr(SessionFactory, "bind", None) or getattr(SessionFactory, "kw", {}).get("bind") or engine
+        pool = bound_engine.pool
+
+        from sqlalchemy import event
+
+        @event.listens_for(pool, "checkout")
+        def _on_checkout(dbapi_conn, conn_record, conn_proxy):
+            sz = pool.size()
+            chk = pool.checkedout()
+            try:
+                conns_in_pool = pool.checkedin()
+            except Exception:
+                conns_in_pool = "?"
+            print(f"POOL CHECKOUT: Pool size: {sz}  Connections in pool: {conns_in_pool} "
+                  f"Current Overflow: {pool.overflow()} Current Checked out connections: {chk} "
+                  f"engine id= {id(bound_engine)}")
+
+        @event.listens_for(pool, "checkin")
+        def _on_checkin(dbapi_conn, conn_record):
+            sz = pool.size()
+            chk = pool.checkedout()
+            try:
+                conns_in_pool = pool.checkedin()
+            except Exception:
+                conns_in_pool = "?"
+            print(f"POOL CHECKIN: Pool size: {sz}  Connections in pool: {conns_in_pool} "
+                  f"Current Overflow: {pool.overflow()} Current Checked out connections: {chk} "
+                  f"engine id= {id(bound_engine)}")
+    except Exception as e:
+        print(f"[crudkit.init_app] Failed to attach pool listeners: {e}")
 
     return runtime