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
For some reason these functions exist in `Backends.Postgres.SQL.Value`.
We don't want to depend on that module here.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/5292
GitOrigin-RevId: a09bd3cdb0caf08938bce0728a8d281344c1d4ce
### 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
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 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
This reduces the usage of "utils" modules in the parsers code, especially those that are simply re-exported from elsewhere, to facilitate extracting the parsers code into its own library.
It mostly inlines the imports that are re-exported from `Hasura.Prelude` and `Data.Parser.JSONPath`. It also removes references to `Data.*.Extended` modules. When necessary, it re-implements the functionality (which is typically trivial).
It does not tackle all external dependencies. I observed the following that will take more work:
- `Data.GADT.Compare.Extended`
- `Data.Text.Extended`
- `Hasura.Base.Error`
- `Hasura.RQL.Types.Common`
- `Hasura.Server.Utils`
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4964
GitOrigin-RevId: 54ad3c1b7a31f13e34340ebe9fcc36d0ad57b8bd
This improves `parseJSONPath` and `encodeJSONPath` to encode special characters appropriately by delegating to Aeson.
This also makes a couple of improvements to `encodeJSONPath`.
1. The function is moved from `Hasura.Base.Error` to `Data.Parser.JSONPath`. This still doesn't seem too appropriate but it is somewhat better. I am basing this on the fact that its test cases already lived in `Data.Parser.JSONPathSpec`.
2. It now returns `Text`, not `String`.
4. It quotes strings with double quotes (`"`) rather than single quotes (`'`), just like JSON.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4935
GitOrigin-RevId: bf44353cd740500245f2e38907a7d6263ae0291c
This reflects the two different usages, which should not be conflated.
We also propagate the type a little more, to avoid `Text`.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4931
GitOrigin-RevId: 16278f14aa4c2cb5667ea54bbb6b25e6d362835c
We only use these `Show` instances in error messages (where we call
`show` explicitly anyway) and test cases (in which Hspec requires `Show
a` for any `a` in an assertion).
This removes the instance in favor of a custom `showQErr` function
(which serializes the error to JSON). It is then used in certain error
message production which previously called `show` on a `QErr`.
There are two places where we serialize a QErr and then construct a new
QErr from the resulting string. Instead, we modify the existing QErr to
add extra information.
An orphan `Show QErr` instance is retained for tests so that we can have
nice test failure messages.
This is preparation for future changes in which the error message within
`QErr` will not be exposed directly, and therefore will not have a
`Show` instance. That said, it feels like a sensible kind of cleanup
anyway.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4897
GitOrigin-RevId: 8f79f7a356f0aea571156f39aefac242bf751f3a
…fix #5426"
This reverts commit f85742318167d1e51f463c45fcd00f26269c2555.
## Description ✍️
With this commit there is the possiblity that you could get conflicting
type definitions with remote schemas. Reverting for now as we determine
a solution. At which point we will add this back in.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4879
Co-authored-by: Gil Mizrahi <8547573+soupi@users.noreply.github.com>
GitOrigin-RevId: 932b4a9226717c826d4bde7e375695354cee8c0c
This came about as I tried to add an instance over catalog versions and
found they were just simple integers most of the time (and in one case,
a float).
I think this change also clarifies how catalog versions work.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4864
GitOrigin-RevId: a6b7db86de564b71a8c2b602bee6a456b8e20d63
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
Pretty much all quasi-quoted names in the server code base have ended up in `Hasura.GraphQL.Parser.Constants`. I'm now finding this unpleasant for two reasons:
1. I would like to factor out the parser code into its own Cabal package, and I don't want to have to expose all these names.
2. Most of them really have nothing to do with the parsers.
In order to remedy this, I have:
1. moved the names used by parser code to `Hasura.GraphQL.Parser.DirectiveName`, as they're all related to directives;
2. moved `Hasura.GraphQL.Parser.Constants` to `Hasura.Name`, changing the qualified import name from `G` to `Name`;
3. moved names only used in tests to the appropriate test case;
4. removed unused items from `Hasura.Name`; and
5. grouped related names.
Most of the changes are simply changing `G` to `Name`, which I find much more meaningful.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4777
GitOrigin-RevId: a77aa0aee137b2b5e6faec94495d3a9fbfa1348b
### Description
This small clean-up PR makes one further step towards backend-agnostic actions: it makes all the code parsing custom types backend agnostic. Surprisingly, this could be done *without* the need to finish generalizing the column parser. The remaining sore point is async queries, that still target Postgres explicitly.
In theory, this is enough to start allowing non-Postgres scalars in custom types. In practice, however:
- no other backend exposes scalars in a way that would allow users to do that as of this PR;
- we currently have no strategy to avoid / detect scalar collisions across backends.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4691
GitOrigin-RevId: bfe63fb131e306663d4406697ce23c02736566c5
(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
### Description
This PR is a first step in a series of cleanups of action relationships. This first step does not contain any behavioral change, and it simply reorganizes / prunes / rearranges / documents the code. Mainly:
- it divides some files in RQL.Types between metadata types, schema cache types, execution types;
- it renames some types for consistency;
- it minimizes exports and prunes unnecessary types;
- it moves some types in places where they make more sense;
- it replaces uses of `DMap BackendTag` with `BackendMap`.
Most of the "movement" within files re-organizes declarations in a "top-down" fashion, by moving all TH splices to the end of the file, which avoids order or declarations mattering.
### Optional list types
One main type change this PR makes is a replacement of variant list types in `CustomTypes.hs`; we had `Maybe [a]`, or sometimes `Maybe (NonEmpty a)`. This PR harmonizes all of them to `[a]`, as most of the code would use them as such, by doing `fromMaybe []` or `maybe [] toList`.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4613
GitOrigin-RevId: bc624e10df587eba862ff27a5e8021b32d0d78a2
