I originally changed the exception name from `ConnectionError` to
`MongoEngineConnectionError` in
b02904ee75,
inspired by landscape.io's package health report, which argued that
`ConnectionError` is already a built-in exception in Python 3 (which it is:
https://docs.python.org/3/library/exceptions.html#ConnectionError).
I do agree that we shouldn't override built-in exceptions. [0] That said, it’s
silly to add a "MongoEngine" prefix to any class within the `mongoengine`
module (and *especially* to *just one* exception class out of many). I've
decided to do what PyMongo does (
8855a510a8/pymongo/errors.py (L59))
and call this exception `ConnectionFailure`.
Note that this is a breaking change and people will need to rename
`MongoEngineConnectionError`s in their code to `ConnectionFailure`. Moreover,
if they use PyMongo's `ConnectionFailure` for anything, they'll need to take
extra care to avoid conflicts, e.g. by using:
```
from mongoengine import ConnectionFailure as MongoEngineConnectionFailure
```
[0] Note that some popular packages still overwrite `ConnectionError`, e.g.
4983a9bde3/requests/exceptions.py (L32)
or
0be4d29206/redis/exceptions.py (L8)
This commit:
1. Formats all of our existing code using `black`.
2. Adds a note about using `black` to `CONTRIBUTING.rst`.
3. Runs `black --check` as part of CI (failing builds that aren't properly formatted).
For example, if you had the following class:
```
class Person(Document):
name = StringField()
age = IntField()
```
You could instantiate an object of such class by doing one of the following:
1. `new_person = Person('Tom', 30)`
2. `new_person = Person('Tom', age=30)`
3. `new_person = Person(name='Tom', age=30)`
From now on, only option (3) is allowed.
Supporting positional arguments may sound like a reasonable idea in this
heavily simplified example, but in real life it's almost never what you want
(especially if you use inheritance in your document definitions) and it may
lead to ugly bugs. We should not rely on the *order* of fields to match a given
value to a given name.
This also helps us simplify the code e.g. by dropping the confusing (and
undocumented) `BaseDocument._auto_id_field` attribute.
For example, if you had the following class:
```
class Person(Document):
name = StringField()
age = IntField()
```
You could instantiate an object of such class by doing one of the following:
1. `new_person = Person('Tom', 30)`
2. `new_person = Person('Tom', age=30)`
3. `new_person = Person(name='Tom', age=30)`
From now on, only option (3) is allowed.
Supporting positional arguments may sound like a reasonable idea in this
heavily simplified example, but in real life it's almost never what you want
(especially if you use inheritance in your document definitions) and it may
lead to ugly bugs. We should not rely on the *order* of fields to match a given
value to a given name.
This also helps us simplify the code e.g. by dropping the confusing (and
undocumented) `BaseDocument._auto_id_field` attribute.
This closes#2096. Previous documentation of the shard_key meta attribute was
missing the crucial point that it really only matters if your collection is
sharded over a compound index.
- expose disconnect
- disconnect cleans _connection_settings
- disconnect cleans cached collection in Document._collection
- re-connecting with the same alias raise an error (must call disconnect in between)
Without this commit save operation on first document would fail instead of immediate failure upon connection attempt. Such later failure is much less obvious.
