Error when passing RLS policies to triggers wrapper

[Niall-Kenny]

Example code:

export const employeeMutation = customMutation(rawMutation, {
  args: { ...employeeArgs },
  input: async (ctx, args) => {
    if (!args.token) {
      throw new ConvexError({
        type: "invalid employee user",
        description: "No token provided",
      })
    }
    const auth = await getCurrentUserHandler(ctx, { token: args.token })
    const employee = auth?.employee

    if (!employee) {
      throw new ConvexError({
        type: "invalid employee user",
        description: "userId",
      })
    }

    return {
      ctx: {
        ...triggers.wrapDB({
          ...ctx,
          db: wrapDatabaseWriter(ctx, ctx.db, employeeRlsRules(ctx, employee), {
            defaultPolicy: "deny",
          }),
        }),
        employee,
      },
      args,
    }
  },
})

Any time I call e.g. ctx.db.patch or ctx.db.get inside a function wrapped by employeeMutation, I get the following error :

TypeError: Cannot read properties of undefined (reading 'get') 
Object.get node_modules/convex-helpers/server/rowLevelSecurity.js:245:28

Its important than RLS policies are adhered to inside the trigger, which is why I haven't wrapped a custom mutation in a trigger wrapper, then wrapped this in am RLS wrapper.

As recommended in the trigger docs, the following works, BUT does not adhere to RLS policies, which is the issue:

const mutationWithTriggers = customMutation(
  rawMutation,
  customCtx(triggers.wrapDB),
)

export const employeeMutation = customMutation(mutationWithTriggers, {
...
      })

[ianmacartney]

Have you diagnosed if the issue goes away if you only apply the wrapDatabaseWriter? Or if you define the wrapped DB before calling triggers.wrapDB?
We haven't seen this before, and it's hard to figure out how the ctx.db would end up undefined.. so adding any logs about the state along the way would be useful.

My only hypothesis is that somewhere it's trying to spread / extract db as an object, when the wrapped DB is actually a class, leading to it becoming unbound from the class instance

[Niall-Kenny]

@ianmacartney cc @Nicolapps

I think the issue is:

wrapDatabaseWriter returns a class, and then triggers.wrapDB returns an object that looks like

{
...
db: {
 get: innerDb.get,
  query: innerDb.query,
  normalizeId: innerDb.normalizeId,
  }
}

and therefore loses the this binding of the WrapWriter (returned by wrapDatabaseWriter) and makes this.reader undefined.

I think all we need to do is exchange the above for:

{
...
db: {
    get: (...args) => innerDb.get(...args),
    query: (...args) => innerDb.query(...args),
    normalizeId: (...args) => innerDb.normalizeId(...args),
  }
}

[Niall-Kenny]

Just did some super ad-hoc testing and it seems to be work after these changes. LMKWYT :)

[ianmacartney]

.bind(innerDb) I think is more idiomatic?