`buildEntities` built every collection as `db.collection(name)` and every
database as `client.db(name)`, dropping `collectionOptions` and
`databaseOptions` on the floor. 15 collection entities declare a
`writeConcern`, 7 a `readConcern`, one a `readPreference` -- and the 15 are all
`{w: 0}`, so every "unacknowledged write" case in this corpus has been running
an acknowledged write against a driver that was never told otherwise.
They passed anyway, because an acknowledged and an unacknowledged write of the
same document produce results a `$$unsetOrMatches` expectation accepts either
way. Only the command on the wire distinguished them, and nothing was reading
the command until the previous commits. This is the first thing the event
assertions found, and it is a fair answer to what they cost.
Option documents are unwrapped from their BSON types on the way to the driver.
The suites are parsed with `relaxed: false`, so `{w: 0}` arrives as an Int32
and the driver gates `writeConcern.w` on `typeof w === 'number'` -- the same
trap NUMERIC_OPTIONS already documents for operation options, and a silent one:
the option would simply not apply. Wholesale unwrapping is safe here in a way
it is not there, since these are settings the driver consumes rather than
values an assertion compares. An option key outside the spec's
`collectionOrDatabaseOptions` set is reported unsupported rather than ignored,
which is the lesson of the bug itself.
159/132/196 becomes 173/118/196. 14 cases fixed, none broken.
The other 10 unacknowledged cases now fail differently, and that is progress
of a sort: with `w: 0` actually applied, the driver refuses client-side to send
`hint` on a delete or findAndModify to a server older than 4.4. This engine
reports itself as 4.4.0 with maxWireVersion 8, and 4.4 is wire 9. That
inconsistency is ours, it is the same one behind the `comment`-on-getMore
failures, and it gets the next commit.
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