### Description
This PR removes `ServerConfigCtx` and `HasServerConfigCtx`. Instead, it favours different approaches:
- when the code was only using one field, it passes that field explicitly (usually `SQLGenCtx` or `CheckFeatureFlag`)
- when the code was using several fields, but in only one function, it inlines
- for the cache build, it introduces `CacheStaticConfig` and `CacheDynamicConfig`, which are subsets of `AppEnv` and `AppContext` respectively
The main goal of this is to help with the modularization of the engine: as `ServerConfigCtx` had fields whose types were imported from several unrelated parts of the engine, using it tied together parts of the engine that should not be aware of one another (such as tying together `Hasura.LogicalModel` and `Hasura.GraphQL.Schema`).
The bulk of this PR is a change to the cache build, as a follow up to #8509: instead of giving the entire `ServerConfigCtx` as a incremental rule argument, we only give the new `CacheDynamicConfig` struct, which has fewer fields. The other required fields, that were coming from the `AppEnv`, are now given via the `HasCacheStaticConfig` constraint, which is a "subset" of `HasAppEnv`.
(Some further work could include moving `StringifyNumbers` out of `GraphQL.Schema.Options`, given how it is used all across the codebase, including in `RQL.DML`.)
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/8513
GitOrigin-RevId: 818cbcd71494e3cd946b06adbb02ca328a8a298e
Mostly trying to avoid tricky `Arrows` syntax, and unnecessary use of the `Hasura.Incremental` framework.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/6997
GitOrigin-RevId: 9a2f5883e7e29af164e1581049ae003afec2cbe4
What is the `Cacheable` type class about?
```haskell
class Eq a => Cacheable a where
unchanged :: Accesses -> a -> a -> Bool
default unchanged :: (Generic a, GCacheable (Rep a)) => Accesses -> a -> a -> Bool
unchanged accesses a b = gunchanged (from a) (from b) accesses
```
Its only method is an alternative to `(==)`. The added value of `unchanged` (and the additional `Accesses` argument) arises _only_ for one type, namely `Dependency`. Indeed, the `Cacheable (Dependency a)` instance is non-trivial, whereas every other `Cacheable` instance is completely boilerplate (and indeed either generated from `Generic`, or simply `unchanged _ = (==)`). The `Cacheable (Dependency a)` instance is the only one where the `Accesses` argument is not just passed onwards.
The only callsite of the `unchanged` method is in the `ArrowCache (Rule m)` method. That is to say that the `Cacheable` type class is used to decide when we can re-use parts of the schema cache between Metadata operations.
So what is the `Cacheable (Dependency a)` instance about? Normally, the output of a `Rule m a b` is re-used when the new input (of type `a`) is equal to the old one. But sometimes, that's too coarse: it might be that a certain `Rule m a b` only depends on a small part of its input of type `a`. A `Dependency` allows us to spell out what parts of `a` are being depended on, and these parts are recorded as values of types `Access a` in the state `Accesses`.
If the input `a` changes, but not in a way that touches the recorded `Accesses`, then the output `b` of that rule can be re-used without recomputing.
So now you understand _why_ we're passing `Accesses` to the `unchanged` method: `unchanged` is an equality check in disguise that just needs some additional context.
But we don't need to pass `Accesses` as a function argument. We can use the `reflection` package to pass it as type-level context. So the core of this PR is that we change the instance declaration from
```haskell
instance (Cacheable a) => Cacheable (Dependency a) where
```
to
```haskell
instance (Given Accesses, Eq a) => Eq (Dependency a) where
```
and use `(==)` instead of `unchanged`.
If you haven't seen `reflection` before: it's like a `MonadReader`, but it doesn't require a `Monad`.
In order to pass the current `Accesses` value, instead of simply passing the `Accesses` as a function argument, we need to instantiate the `Given Accesses` context. We use the `give` method from the `reflection` package for that.
```haskell
give :: forall r. Accesses -> (Given Accesses => r) -> r
unchanged :: (Given Accesses => Eq a) => Accesses -> a -> a -> Bool
unchanged accesses a b = give accesses (a == b)
```
With these three components in place, we can delete the `Cacheable` type class entirely.
The remainder of this PR is just to remove the `Cacheable` type class and its instances.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/6877
GitOrigin-RevId: 7125f5e11d856e7672ab810a23d5bf5ad176e77f
This upgrades the version of Ormolu required by the HGE repository to v0.5.0.1, and reformats all code accordingly.
Ormolu v0.5 reformats code that uses infix operators. This is mostly useful, adding newlines and indentation to make it clear which operators are applied first, but in some cases, it's unpleasant. To make this easier on the eyes, I had to do the following:
* Add a few fixity declarations (search for `infix`)
* Add parentheses to make precedence clear, allowing Ormolu to keep everything on one line
* Rename `relevantEq` to `(==~)` in #6651 and set it to `infix 4`
* Add a few _.ormolu_ files (thanks to @hallettj for helping me get started), mostly for Autodocodec operators that don't have explicit fixity declarations
In general, I think these changes are quite reasonable. They mostly affect indentation.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/6675
GitOrigin-RevId: cd47d87f1d089fb0bc9dcbbe7798dbceedcd7d83
Context: https://hasurahq.atlassian.net/browse/SRE-10
Also remove an overlapping instance.
-----
The new flags if this needs to be tweaked on production by SRE are:
- --idleGCIdleInterval : "When the system has been idle for idleGCIdleInterval we may opportunistically try a major GC to run finalizers"
- --idleGCMinGCInterval : "We never run an opportunistic GC unless it has been at least idleGCMinGCInterval seconds since the last major GC"
- --idleGCMaxNoGCInterval : "If it has been longer than idleGCMaxNoGCInterval since the last major GC, force a GC to run finalizers"
Be aware: we may see memory usage grow to higher peaks than before, especially when under load
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/6449
GitOrigin-RevId: 662d2f968f0d73b3b6eebb857c49aaede3312705
