Losing KeyIn/KeyOut type parameters when using directories

[NuckChorris]

Whenever I use .at with a directory, it loses my key/value encoders, see following including the types reported in VS Code:

import fdb from 'foundationdb';

fdb.setAPIVersion(620);

const rootDb = fdb.open().withKeyEncoding(fdb.tuple);

const directorySubspace = rootDb.at(await fdb.directory.createOrOpen(rootDb, 'test'));
// const directorySubspace: fdb.Database<NativeValue, Buffer, NativeValue, Buffer>

const stringSubspace = rootDb.at('test');
// const stringSubspace: fdb.Database<string | number | boolean | Buffer | BigInt | TupleArr | {
//     type: "uuid";
//     value: Buffer;
// } | {
//     type: "float";
//     value: number;
//     rawEncoding?: Buffer | undefined;
// } | ... 5 more ... | undefined, fdb.TupleItem[], NativeValue, Buffer>

As you can see, it works fine if my subspace is a string prefix, but a directory prefix seems to break the type and lose my key/value encoders :(

[NuckChorris]

Actually these types may be accurate, it seems like .at with a directory resets the encoders, which seems... odd? Is this behavior intentional?

[josephg]

Yes, it is odd - and its certainly not ideal. When I wrote it I wasn't sure what the behaviour should be in this case, and the directory layer code is mostly ported directly from the python bindings to keep things simple. I'm having a re-read of the code to see how it could be improved. It seems like a pretty obvious fix to plumb the KV transformers through.

The problem is when you call DirectoryLayer#createOrOpen like this:

fdb.directory.createOrOpen(rootDb, 'test')

It doesn't inherit the KV transformers from the passed database.

The relevant code is here. If you follow that down, contentSubspaceForNode should take an optional subspace and then we can plumb your rootDb through.

You're welcome to put together a PR. We'll have to bump the major version number because it'll be a semver-breaking change.

[josephg]

... I've thrown together the first pass of a fix for this. I don't like the template parameters everywhere, but I think its the right solution. Your example should work with the new code.

[josephg]

... And I published it as foundationdb@2. Give it a try and let me know if there are any problems. Windows support has been removed for now due to this issue.