GraphQL types can refer to each other in a circular way. The PDV framework used to use values of type `Unique` to recognize two fragments of GraphQL schema as being the same instance. Internally, this is based on `Data.Unique` from the `base` package, which simply increases a counter on every creation of a `Unique` object.
**NB**: The `Unique` values are _not_ used for knot tying the schema combinators themselves (i.e. `Parser`s). The knot tying for `Parser`s is purely based on keys provided to `memoizeOn`. The `Unique` values are _only_ used to recognize two pieces of GraphQL _schema_ as being identical. Originally, the idea was that this would help us with a perfectly correct identification of GraphQL types. But this fully correct equality checking of GraphQL types was never implemented, and does not seem to be necessary to prevent bugs.
Specifically, these `Unique` values are stored as part of `data Definition a`, which specifies a part of our internal abstract syntax tree for the GraphQL types that we expose. The `Unique` values get initialized by the `SchemaT` effect.
In #2894 and #2895, we are experimenting with how (parts of) the GraphQL types can be hidden behind certain permission predicates. This would allow a single GraphQL schema in memory to serve all roles, implementing #2711. The permission predicates get evaluated at query parsing time when we know what role is doing a certain request, thus outputting the correct GraphQL types for that role.
If the approach of #2895 is followed, then the `Definition` objects, and thus the `Unique` values, would be hidden behind the permission predicates. Since the permission predicates are evaluated only after the schema is already supposed to be built, this means that the permission predicates would prevent us from initializing the `Unique` values, rendering them useless.
The simplest remedy to this is to remove our usage of `Unique` altogether from the GraphQL schema and schema combinators. It doesn't serve a functional purpose, doesn't prevent bugs, and requires extra bookkeeping.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/2980
GitOrigin-RevId: 50d3f9e0b9fbf578ac49c8fc773ba64a94b1f43d
Source typename customization (hasura/graphql-engine@aac64f2c81) introduced a mechanism to change certain names in the GraphQL schema that is exposed. In particular it allows last-minute modification of:
1. the names of some types, and
2. the names of some root fields.
The above two items are assigned distinct customization algorithms, and at times both algorithms are in scope. So a need to distinguish them is needed.
In the original design, this was addressed by introducing a newtype wrapper `Typename` around GraphQL `Name`s, dedicated to the names of types. However, in the majority of the codebase, type names are also represented by `Name`. For this reason, it was unavoidable to allow for easy conversion. This was supported by a `HasName Typename` instance, as well as by publishing the constructors of `Typename`.
This means that the type safety that newtypes can add is lost. In particular, it is now very easy to confuse type name customization with root field name customization.
This refactors the above design by instead introducing newtypes around the customization operations:
```haskell
newtype MkTypename = MkTypename {runMkTypename :: Name -> Name}
deriving (Semigroup, Monoid) via (Endo Name)
newtype MkRootFieldName = MkRootFieldName {runMkRootFieldName :: Name -> Name}
deriving (Semigroup, Monoid) via (Endo Name)
```
The `Monoid` instance allows easy composition of customization operations, piggybacking off of the type of `Endo`maps.
This design allows safe co-existence of the two customization algorithms, while avoiding the syntactic overhead of packing and unpacking newtypes.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/2989
GitOrigin-RevId: da3a353a9b003ee40c8d0a1e02872e99d2edd3ca
This commit applies ormolu to the whole Haskell code base by running `make format`.
For in-flight branches, simply merging changes from `main` will result in merge conflicts.
To avoid this, update your branch using the following instructions. Replace `<format-commit>`
by the hash of *this* commit.
$ git checkout my-feature-branch
$ git merge <format-commit>^ # and resolve conflicts normally
$ make format
$ git commit -a -m "reformat with ormolu"
$ git merge -s ours post-ormolu
https://github.com/hasura/graphql-engine-mono/pull/2404
GitOrigin-RevId: 75049f5c12f430c615eafb4c6b8e83e371e01c8e
