>
## Description
->
This PR allows DC agents to define custom aggregate functions for their scalar types.
### Related Issues
->
GDC-189
### Solution and Design
>
We added a new property `aggregate_functions` to the scalar types capabilities. This allows the agent author to specify a set of aggregate functions supported by each scalar type, along with the function's result type.
During GraphQL schema generation, the custom aggregate functions are available via a new method `getCustomAggregateOperators` on the `Backend` type class.
Custom functions are merged with the builtin aggregate functions when building GraphQL schemas for table aggregate fields and for `order_by` operators on array relations.
### Steps to test and verify
>
• Codec tests for aggregate function capabilities have been added to the unit tests.
• Some custom aggregate operators have been added to the reference agent and are used in a new test in `api-tests`.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/6199
GitOrigin-RevId: e9c0d1617af93847c1493671fdbb794f573bde0c
>
## Description ✍️
->
Fleshes out the Capabilities types used by Data Connector agents.
### Related Issues ✍
->
https://hasurahq.atlassian.net/browse/GDW-85
### Solution and Design ✍
>
Capabilities are divided into sections for queries, mutation, subscriptions, filtering and relationships:
```haskell
data Capabilities = Capabilities
{ cQueries :: Maybe QueryCapabilities,
cMutations :: Maybe MutationCapabilities,
cSubscriptions :: Maybe SubscriptionCapabilities,
cFiltering :: Maybe FilteringCapabilities,
cRelationships :: Maybe RelationshipCapabilities
}
```
Each section is optional. If the section is absent it means the the related capabilities are not supported by the agent.
The types for each section can contain additional details about exactly what is supported. E.g.
```haskell
data QueryCapabilities = QueryCapabilities
{ qcSupportsPrimaryKeys :: Bool
}
```
These are currently mostly empty, but will be filled in later.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/4671
GitOrigin-RevId: 3d48570266bfce5e177a543a0ed6f63a7b450f0b
>
## 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
