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
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
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
This PR moves Hasura-specific schema functions from `Hasura.GraphQL.Parser.Class` into `Hasura.GraphQL.Schema.Common`. It also removes the two corresponding monad aliases, and consequently harmonizes several parts of the code to use the same common constraint.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3947
GitOrigin-RevId: 40985a7d86da97a311bd480f9a57cc18c350c2a8
We build the GraphQL schema by combining building blocks such as `tableSelectionSet` and `columnParser`. These building blocks individually build `{InputFields,Field,}Parser` objects. Those object specify the valid GraphQL schema.
Since the GraphQL schema is role-dependent, at some point we need to know what fragment of the GraphQL schema a specific role is allowed to access, and this is stored in `{Sel,Upd,Ins,Del}PermInfo` objects.
We have passed around these permission objects as function arguments to the schema building blocks since we first started dealing with permissions during the PDV refactor - see hasura/graphql-engine@5168b99e46 in hasura/graphql-engine#4111. This means that, for instance, `tableSelectionSet` has as its type:
```haskell
tableSelectionSet ::
forall b r m n.
MonadBuildSchema b r m n =>
SourceName ->
TableInfo b ->
SelPermInfo b ->
m (Parser 'Output n (AnnotatedFields b))
```
There are three reasons to change this.
1. We often pass a `Maybe (xPermInfo b)` instead of a proper `xPermInfo b`, and it's not clear what the intended semantics of this is. Some potential improvements on the data types involved are discussed in issue hasura/graphql-engine-mono#3125.
2. In most cases we also already pass a `TableInfo b`, and together with the `MonadRole` that is usually also in scope, this means that we could look up the required permissions regardless: so passing the permissions explicitly undermines the "single source of truth" principle. Breaking this principle also makes the code more difficult to read.
3. We are working towards role-based parsers (see hasura/graphql-engine-mono#2711), where the `{InputFields,Field,}Parser` objects are constructed in a role-invariant way, so that we have a single object that can be used for all roles. In particular, this means that the schema building blocks _need_ to be constructed in a role-invariant way. While this PR doesn't accomplish that, it does reduce the amount of role-specific arguments being passed, thus fixing hasura/graphql-engine-mono#3068.
Concretely, this PR simply drops the `xPermInfo b` argument from almost all schema building blocks. Instead these objects are looked up from the `TableInfo b` as-needed. The resulting code is considerably simpler and shorter.
One way to interpret this change is as follows. Before this PR, we figured out permissions at the top-level in `Hasura.GraphQL.Schema`, passing down the obtained `xPermInfo` objects as required. After this PR, we have a bottom-up approach where the schema building blocks themselves decide whether they want to be included for a particular role.
So this moves some permission logic out of `Hasura.GraphQL.Schema`, which is very complex.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3608
GitOrigin-RevId: 51a744f34ec7d57bc8077667ae7f9cb9c4f6c962
This PR simplifies the types that represent a remote relationship in IR so that they can be reused in other parts (in remote schema types) which could have remote relationships.
The comments on the PR explain the main changes.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/2979
GitOrigin-RevId: 559c51d9d6ae79e2183ce4347018741b9096ac74
