[19.0][MIG] ai_oca_mcp

[OmniaGit]

Migration of ai_oca_mcp to 19.0.

Depends on #101 ([19.0][MIG] ai_tool) — until that one is merged this PR also carries the ai_tool commits; they disappear on rebase.

The module is not on 18.0 yet, so the history replayed here is the one from #76: this builds directly on @angelmoya's 16.0 → 18.0 work rather than redoing it, and their commits are preserved as authored.

Three changes beyond the version bump.

_sql_constraints → models.Constraint

In 19.0 the ORM logs "Model attribute '_sql_constraints' is no longer supported, please define models.Constraint on the model" (odoo/orm/model_classes.py) and does not create the constraint. The unique keys on mcp.server and mcp.server.key are now declared as models.Constraint("unique (…)", …).

expire_key() cache invalidation

_get_mcp_server_by_key is an ormcache, and expire_key() invalidated it through self._get_mcp_server_by_key.clear_cache(self). In 19.0 the decorator only sets lookup.__cache__, so that attribute no longer exists and the call raises AttributeError — which rolls the transaction back, meaning the key is not revoked at all, and the controller path that expires a key past its expiration_date answers 500 instead of rejecting the request.

The replacement is self.env.registry.clear_cache(). Same scope as before, in both directions: the old clear_cache ignored its arguments and called model.pool._clear_cache(), and the new one defaults to the default cache bucket, which is where this ormcache lives.

readonly=False on the route

This one is not specific to 19.0 and is worth a look on #76 as well.

Since 18.0, a route declared with auth="none" is served with a read-only cursor unless it says otherwise:

default_mode = submethod.original_routing.get('readonly', default_auth == 'none')

The MCP endpoint is auth="none" and writes — it logs every call to mcp.server.log, and expires keys. So on 18.0 and 19.0 every request runs, fails on the first INSERT, and is replayed from the top by service_model.retrying with a read/write cursor:

ERROR odoo.sql_db: bad query: INSERT INTO "mcp_server_log" …
ERROR: cannot execute INSERT in a read-only transaction
WARNING odoo.http: cannot execute INSERT in a read-only transaction, retrying with a read/write cursor

It works — the retry is why the test suite is green either way — but every MCP call is executed twice and every call leaves two ERROR lines in the log. Declaring the route readonly=False fixes it; the module's own tests go from 131 to 119 queries.

Testing

Odoo 19.0-20260803, ai_tool and ai_oca_mcp installed together: 15 tests, 0 failed, 0 errors, and no read-only retries left in the log.

Not included, on purpose

This is a migration. The protocol version answered at initialize is still the hardcoded 2025-03-26 and ping still falls through to "Method not found" — both worth addressing, both in separate PRs.

@etobella @angelmoya, in the context of #73.