Hello,
I'm a new developer in odoo and I have 3 months that I have started. During a task that was given me by my company I work with I had this problem which affected all databases and not just only one.
I was working in a report for odoo Point Of Sale and my goal was to take some variable values which included the money a session in pos ends. So I made a module inheriting "pos.session" and after looking at it, the module was working fine but there was still little things to be added. While changing the code I ended up with a recursion error and even though I stopped the service, the database somehow affected other databases.
I'm working on odoo12 and the error that it gives me is:

Traceback (most recent call last):
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/modules/registry.py", line 60, in __new__
    return cls.registries[db_name]
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/tools/func.py", line 69, in wrapper
    return func(self, *args, **kwargs)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/tools/lru.py", line 44, in __getitem__
    a = self.d[obj].me
KeyError: 'bardemo'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/modules/registry.py", line 86, in new
    odoo.modules.load_modules(registry._db, force_demo, status, update_module)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/modules/loading.py", line 430, in load_modules
    registry.setup_models(cr)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/modules/registry.py", line 274, in setup_models
    model._setup_fields()
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/models.py", line 2658, in _setup_fields
    field.setup_full(self)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/fields.py", line 520, in setup_full
    self._setup_related_full(model)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/fields.py", line 1392, in _setup_related_full
    super(Monetary, self)._setup_related_full(model)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/fields.py", line 563, in _setup_related_full
    field = target._fields[name]
KeyError: ''
2022-05-26 08:16:11,366 10550 INFO bardemo werkzeug: 192.168.1.69 - - [26/May/2022 08:16:11] "GET /favicon.ico HTTP/1.1" 500 - 13 0.017 0.424
2022-05-26 08:16:11,372 10550 ERROR bardemo werkzeug: Error on request:
Traceback (most recent call last):
  File "/home/thecowmilk/Development/odoo12/odoo/venv/lib/python3.8/site-packages/werkzeug/serving.py", line 205, in run_wsgi
    execute(self.server.app)
  File "/home/thecowmilk/Development/odoo12/odoo/venv/lib/python3.8/site-packages/werkzeug/serving.py", line 193, in execute
    application_iter = app(environ, start_response)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/service/server.py", line 436, in app
    return self.app(e, s)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/service/wsgi_server.py", line 142, in application
    return application_unproxied(environ, start_response)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/service/wsgi_server.py", line 117, in application_unproxied
    result = odoo.http.root(environ, start_response)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/http.py", line 1320, in __call__
    return self.dispatch(environ, start_response)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/http.py", line 1293, in __call__
    return self.app(environ, start_wrapped)
  File "/home/thecowmilk/Development/odoo12/odoo/venv/lib/python3.8/site-packages/werkzeug/wsgi.py", line 599, in __call__
    return self.app(environ, start_response)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/http.py", line 1471, in dispatch
    odoo.registry(db).check_signaling()
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/__init__.py", line 117, in registry
    return modules.registry.Registry(database_name)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/modules/registry.py", line 62, in __new__
    return cls.new(db_name)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/modules/registry.py", line 86, in new
    odoo.modules.load_modules(registry._db, force_demo, status, update_module)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/modules/loading.py", line 430, in load_modules
    registry.setup_models(cr)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/modules/registry.py", line 274, in setup_models
    model._setup_fields()
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/models.py", line 2658, in _setup_fields
    field.setup_full(self)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/fields.py", line 520, in setup_full
    self._setup_related_full(model)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/fields.py", line 1392, in _setup_related_full
    super(Monetary, self)._setup_related_full(model)
  File "/home/thecowmilk/Development/odoo12/odoo/odoo/fields.py", line 563, in _setup_related_full
    field = target._fields[name]
KeyError: '' - - -