Followup to hasura/graphql-engine-mono#4713.
The `memoizeOn` method, part of `MonadSchema`, originally had the following type:
```haskell
memoizeOn
:: (HasCallStack, Ord a, Typeable a, Typeable b, Typeable k)
=> TH.Name
-> a
-> m (Parser k n b)
-> m (Parser k n b)
```
The reason for operating on `Parser`s specifically was that the `MonadSchema` effect would additionally initialize certain `Unique` values, which appear (nested in) the type of `Parser`.
hasura/graphql-engine-mono#518 changed the type of `memoizeOn`, to additionally allow memoizing `FieldParser`s. These also contained a `Unique` value, which was similarly initialized by the `MonadSchema` effect. The new type of `memoizeOn` was as follows:
```haskell
memoizeOn
:: forall p d a b
. (HasCallStack, HasDefinition (p n b) d, Ord a, Typeable p, Typeable a, Typeable b)
=> TH.Name
-> a
-> m (p n b)
-> m (p n b)
```
Note the type `p n b` of the value being memoized: by choosing `p` to be either `Parser k` or `FieldParser`, both can be memoized. Also note the new `HasDefinition (p n b) d` constraint, which provided a `Lens` for accessing the `Unique` value to be initialized.
A quick simplification is that the `HasCallStack` constraint has never been used by any code. This was realized in hasura/graphql-engine-mono#4713, by removing that constraint.
hasura/graphql-engine-mono#2980 removed the `Unique` value from our GraphQL-related types entirely, as their original purpose was never truly realized. One part of removing `Unique` consisted of dropping the `HasDefinition (p n b) d` constraint from `memoizeOn`.
What I didn't realize at the time was that this meant that the type of `memoizeOn` could be generalized and simplified much further. This PR finally implements that generalization. The new type is as follows:
```haskell
memoizeOn ::
forall a p.
(Ord a, Typeable a, Typeable p) =>
TH.Name ->
a ->
m p ->
m p
```
This change has a couple of consequences.
1. While constructing the schema, we often output `Maybe (Parser ...)`, to model that the existence of certain pieces of GraphQL schema sometimes depends on the permissions that a certain role has. The previous versions of `memoizeOn` were not able to handle this, as the only thing they could memoize was fully-defined (if not yet fully-evaluated) `(Field)Parser`s. This much more general API _would_ allow memoizing `Maybe (Parser ...)`s. However, we probably have to be continue being cautious with this: if we blindly memoize all `Maybe (Parser ...)`s, the resulting code may never be able to decide whether the value is `Just` or `Nothing` - i.e. it never commits to the existence-or-not of a GraphQL schema fragment. This would manifest as a non-well-founded knot tying, and this would get reported as an error by the implementation of `memoizeOn`.
tl;dr: This generalization _technically_ allows for memoizing `Maybe` values, but we probably still want to avoid doing so.
For this reason, the PR adds a specialized version of `memoizeOn` to `Hasura.GraphQL.Schema.Parser`.
2. There is no longer any need to connect the `MonadSchema` knot-tying effect with the `MonadParse` effect. In fact, after this PR, the `memoizeOn` method is completely GraphQL-agnostic, and so we implement hasura/graphql-engine-mono#4726, separating `memoizeOn` from `MonadParse` entirely - `memoizeOn` can be defined and implemented as a general Haskell typeclass method.
Since `MonadSchema` has been made into a single-type-parameter type class, it has been renamed to something more general, namely `MonadMemoize`. Its only task is to memoize arbitrary `Typeable p` objects under a combined key consisting of a `TH.Name` and a `Typeable a`.
Also for this reason, the new `MonadMemoize` has been moved to the more general `Control.Monad.Memoize`.
3. After this change, it's somewhat clearer what `memoizeOn` does: it memoizes an arbitrary value of a `Typeable` type. The only thing that needs to be understood in its implementation is how the manual blackholing works. There is no more semantic interaction with _any_ GraphQL code.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4725
Co-authored-by: Daniel Harvey <4729125+danieljharvey@users.noreply.github.com>
GitOrigin-RevId: 089fa2e82c2ce29da76850e994eabb1e261f9c92
### Description
By definition, root fields are at the root of the schema: only functions that craft root fields need to know about how to customize the name of root fields. However, the presence of `Has MkRootFieldName` in `MonadBuildSchemaBase` meant that the entirety of the schema building code was implicitly aware of / capable of altering root field names.
This PR removes this constraint, and moves it to the functions that do craft root fields. This has several upsides:
- it makes it more explicit where root fields are being crafted
- it prevents functions that should not use this from mistakenly applying it to non-root fields
- it simplifies the shared schema context
### Future work
- can we maybe pass this as an argument, instead of making it a required part of the context?
- ~~AFAICT, we only ever use `mempty` for it: is this actually dead code that we should actually just remove altogether?~~
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/5235
GitOrigin-RevId: 4268751f3ab87ae8e03b6fe9e1efa1b096200027
### Description
I am not 100% sure about this PR; while I think the code is better this way, I'm willing to be convinced otherwise.
In short, this PR moves the `RoleName` field into the `SchemaContext`, instead of being a nebulous `Has RoleName` constraint on the reader monad. The major upside of this is that it makes it an explicit named field, rather than something that must be given as part of a tuple of arguments when calling `runReader`.
However, the downside is that it breaks the helper permissions functions of `Schema.Table`, which relied on `Has RoleName r`. This PR makes the choice of passing the role name explicitly to all of those functions, which in turn means first explicitly fetching the role name in a lot of places. It makes it more explicit when a schema building block relies on the role name, but is a bit verbose...
### Alternatives
Some alternatives worth considering:
- attempting something like `Has context r, Has RoleName context`, which would allow them to be independent from the context but still fetch the role name from the reader, but might require type annotations to not be ambiguous
- keeping the permission functions the same, with `Has RoleName r`, and introducing a bunch of newtypes instead of using tuples to explicitly implement all the required `Has` instances
- changing the permission functions to `Has SchemaContext r`, since they are functions used only to build the schema, and therefore may be allowed to be tied to the context.
What do y'all think?
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/5073
GitOrigin-RevId: 8fd09fafb54905a4d115ef30842d35da0c3db5d2
In the process of decoupling the schema parsers from the GraphQL Engine, we need to remove dependencies on `Hasura.Base.Error`.
First of all, we have avoided using `QErr` in schema parsers code, instead returning a more appropriate data type which can be converted to a `Hasura.Base.Error.QErr` later.
Secondly, we create a new `ParseErrorCode` type to represent parse failure types, which are then converted to a `Hasura.Base.Error.Code` later.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/5181
GitOrigin-RevId: 8655e26adb1e7d5e3d552c77a8a403f987b53467
Updates to the latest version of autodocodec and uses the new features, in particular `discriminatedUnionCodec`.
This allows us to remove the `ValueWrapper*` types and `sumTypeCodec`. Sum types are now encoded as discriminated unions.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/5155
GitOrigin-RevId: 20bfdc12b28d35db354c4a149b9175fab0b2b7d2
This introduces an `ErrorMessage` newtype which wraps `Text` in a manner which is designed to be easy to construct, and difficult to deconstruct.
It provides functionality similar to `Data.Text.Extended`, but designed _only_ for error messages. Error messages are constructed through `fromString`, concatenation, or the `toErrorValue` function, which is designed to be overridden for all meaningful domain types that might show up in an error message. Notably, there are not and should never be instances of `ToErrorValue` for `String`, `Text`, `Int`, etc. This is so that we correctly represent the value in a way that is specific to its type. For example, all `Name` values (from the _graphql-parser-hs_ library) are single-quoted now; no exceptions.
I have mostly had to add `instance ToErrorValue` for various backend types (and also add newtypes where necessary). Some of these are not strictly necessary for this changeset, as I had bigger aspirations when I started. These aspirations have been tempered by trying and failing twice.
As such, in this changeset, I have started by introducing this type to the `parseError` and `parseErrorWith` functions. In the future, I would like to extend this to the `QErr` record and the various `throwError` functions, but this is a much larger task and should probably be done in stages.
For now, `toErrorMessage` and `fromErrorMessage` are provided for conversion to and from `Text`, but the intent is to stop exporting these once all error messages are converted to the new type.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/5018
GitOrigin-RevId: 84b37e238992e4312255a87ca44f41af65e2d89a
This removes the one remaining instance of `unsafeMkName` in production
code, uses `G.name` where possible in tests, and ignores instances where
it's not possible (such as `instance Arbitrary G.Name`).
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/5074
GitOrigin-RevId: d8049edf1f1bc2ef25f34874ef5bd5a5934bd33d
### Description
A trivial PR, extracted out of #4936, that removes remote schema permissions from the schema context, as they are only ever used at the top level: whether or not we need to use remote schema permissions is not something that impacts _how_ we build the schema, but whether some parts of the schema should be built at all, and therefore doesn't need to be accessible throughout the build process.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/5050
GitOrigin-RevId: 734673370393d5640ad753222982baf2698f6d8f
This moves `MkTypename` and `NamingCase` into their own modules, with the intent of reducing the scope of the schema parsers code, and trying to reduce imports of large modules when small ones will do.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4978
GitOrigin-RevId: 19541257fe010035390f6183a4eaa37bae0d3ca1
Earlier, if the `select` root field had a custom root field set, the same custom root field was then used for the streaming subscription root field as well. This leads to duplicate root fields being generated in the `subscription_root`.
This PR fixes that. It provides a way to customize the streaming subscription root field and not use the `select` root field's custom root field name for the streaming subscription root field.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4967
Co-authored-by: Anon Ray <616387+ecthiender@users.noreply.github.com>
GitOrigin-RevId: 54e74ce97561b0e5cfdfc60d1ca340aaebecf7d4
The code that builds the GraphQL schema, and `buildGQLContext` in particular, is partial: not every value of `(ServerConfigCtx, GraphQLQueryType, SourceCache, HashMap RemoteSchemaName (RemoteSchemaCtx, MetadataObject), ActionCache, AnnotatedCustomTypes)` results in a valid GraphQL schema. When it fails, we want to be able to return better error messages than we currently do.
The key thing that is missing is a way to trace back GraphQL type information to their origin from the Hasura metadata. Currently, we have a number of correctness checks of our GraphQL schema. But these correctness checks only have access to pure GraphQL type information, and hence can only report errors in terms of that. Possibly the worst is the "conflicting definitions" error, which, in practice, can only be debugged by Hasura engineers. This is terrible DX for customers.
This PR allows us to print better error messages, by adding a field to the `Definition` type that traces the GraphQL type to its origin in the metadata. So the idea is simple: just add `MetadataObjId`, or `Maybe` that, or some other sum type of that, to `Definition`.
However, we want to avoid having to import a `Hasura.RQL` module from `Hasura.GraphQL.Parser`. So we instead define this additional field of `Definition` through a new type parameter, which is threaded through in `Hasura.GraphQL.Parser`. We then define type synonyms in `Hasura.GraphQL.Schema.Parser` that fill in this type parameter, so that it is not visible for the majority of the codebase.
The idea of associating metadata information to `Definition`s really comes to fruition when combined with hasura/graphql-engine-mono#4517. Their combination would allow us to use the API of fatal errors (just like the current `MonadError QErr`) to report _inconsistencies_ in the metadata. Such inconsistencies are then _automatically_ ignored. So no ad-hoc decisions need to be made on how to cut out inconsistent metadata from the GraphQL schema. This will allow us to report much better errors, as well as improve the likelihood of a successful HGE startup.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4770
Co-authored-by: Samir Talwar <47582+SamirTalwar@users.noreply.github.com>
GitOrigin-RevId: 728402b0cae83ae8e83463a826ceeb609001acae
(Work here originally done by awjchen, rebased and fixed up for merge by
jberryman)
This is part of a merge train towards GHC 9.2 compatibility. The main
issue is the use of the new abstract `KeyMap` in 2.0. See:
https://hackage.haskell.org/package/aeson-2.0.3.0/changelog
Alex's original work is here:
#4305
BEHAVIOR CHANGE NOTE: This change causes a different arbitrary ordering
of serialized Json, for example during metadata export. CLI users care
about this in particular, and so we need to call it out as a _behavior
change_ as we did in v2.5.0. The good news though is that after this
change ordering should be more stable (alphabetical key order).
See: https://hasurahq.slack.com/archives/C01M20G1YRW/p1654012632634389
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4611
Co-authored-by: awjchen <13142944+awjchen@users.noreply.github.com>
GitOrigin-RevId: 700265162c782739b2bb88300ee3cda3819b2e87
## Motivation
This PR rewrites most of Relay to achieve the following:
- ~~fix a bug in which the same node id could refer to two different tables in the schema~~
- remove one of the few remaining uses of the source cache in the schema building code
In doing so, it also:
- simplifies the `BackendSchema` class by removing `node` from it,
- makes it much easier for other backends to support Relay,
- documents, re-organizes, and clarifies the code.
## Description
This PR introduces a new `NodeId` version ~~, and adapts the Postgres code to always generate this V2 version~~. This new id contains the source name, in addition to the table name, in order to disambiguate similar table names across different sources (which is now possible with source customization). In doing so, it now explicitly handles that case for V1 node ids, and returns an explicit error message instead of running the risk of _silently returning the wrong information_.
Furthermore, it adapts `nodeField` to support multiple backends; most of the code was trivial to generalize, and as a result it lowers the cost of entry for other backends, that now only need to support `AFNodeId` in their translation layer.
Finally, it removes one more cycle in the schema building code, by using the same trick we used for remote relationships instead of using the memoization trick of #4576.
## Remaining work
- ~~[ ]write a Changelog entry~~
- ~~[x] adapt all tests that were asserting on an old node id~~
## Future work
This PR was adapted from its original form to avoid a breaking change: while it introduces a Node ID V2, we keep generating V1 IDs and the parser rejects V2 IDs. It will be easy to make the switch at a later data in a subsequent PR.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4593
GitOrigin-RevId: 88e5cb91e8b0646900547fa8c7c0e1463de267a1
This is a first step towards clarifying the role of `UnpreparedValue` as part of the IR. It certainly does not belong in the parser framework.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4588
GitOrigin-RevId: d1582a0b266729b79e00d31057178a4099168e6d
### Description
The main goal of this PR is, as stated, to remove the circular dependency in the schema building code. This cycle arises from the existence of remote relationships: when we build the schema for a source A, a remote relationship might force us to jump to the schema of a source B, or some remote schema. As a result, we end up having to do a dispatch from a "leaf" of the schema, similar to the one done at the root. In turn, this forces us to carry along in the schema a lot of information required for that dispatch, AND it forces us to import the instances in scope, creating an import loop.
As discussed in #4489, this PR implements the "dependency injection" solution: we pass to the schema a function to call to do the dispatch, and to get a generated field for a remote relationship. That way, this function can be chosen at the root level, and the leaves need not be aware of the overall context.
This PR grew a bit bigger than that, however; in an attempt to try and remove the `SourceCache` from the schema altogether, it changed a lot of functions across the schema building code, to thread along the `SourceInfo b` of the source being built. This avoids having to do cache lookups within a given source. A few cases remain, such as relay, that we might try to tackle in a subsequent PR.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4557
GitOrigin-RevId: 9388e48372877520a72a9fd1677005df9f7b2d72
## Description
Hopefully this is relatively self-explanatory: this change splits the helper functions we've used to extend QuickCheck from the orphan instances and generators that we have defined for unit tests. These have now been placed in `Test.QuickCheck.Extended` and `Hasura.QuickCheck.Instances`, respectively.
This change also adds some documentation to the functions defined in `Test.QuickCheck.Extended` in the spirit of similar functions defined by `Test.QuickCheck`, itself.
### Motivation
We should adhere to the existing convention of constructing "extension modules" for common libraries separately from the code that takes advantage of these.
Alone, this wouldn't be a reason to split up `Hasura.Generators`, but we should **also** follow a convention of defining **all** orphan instances in modules whose names clearly indicate that they exist solely for the purpose of exporting these orphan instances (e.g. `Hasura.QuickCheck.Instances`).
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3747
GitOrigin-RevId: fb856a790b4a39163f81481d4f900fafb1797ea6
