### 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
## 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
>
## Description ✍️
- Creates a new `/capabilities` endpoint for the GDC agent API
- Removes capabilities from the `/schema` endpoint
- Removes the `/config-schema` endpoint and includes the `ConfigSchemaResponse` within the `CapabilitiesResponse`
### Related Issues ✍
->
https://hasurahq.atlassian.net/browse/GDW-85
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4478
GitOrigin-RevId: 426662ee9e751343d94207d439a5025df65d2de7
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
Several places in the code used `a /= []`, which is inelegant. To my surprise, hlint did not warn about this, despite the fact that it forces an `Eq` instance on the elements. This PR replaces all occurrences of that pattern with `not (null a)` and adds a lint warning for it.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4569
GitOrigin-RevId: 6471e75ade9e71e5d583a0dac7815c01870c696b
### Description
As part of the cache building process, we create / update / migrate the catalog that each DB uses as a place to store event trigger information. The function that decides how this should be done was doing an explicit `case ... of` on the backend tag, instead of delegating to one of the backend classes. The downsides of this is that:
- it adds a "friction point" where the backend matters in the core of the engine, which is otherwise written to be almost entirely backend-agnostic
- it creates imports from deep in the engine to the `Backends`, which we try to restrict to a very small set of clearly identified files (the `Instances` files)
- it is currently implemented using a "catch all" default case, which might not always be correct for new backends
This PR makes the catalog updating process a part of `BackendMetadata`, and cleans the corresponding schema cache code.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4457
GitOrigin-RevId: 592f0eaa97a7c38f4e6d4400e1d2353aab12c97e
