### Motivation
While we strive to write clear code, we have historically struggled at Hasura with having very different styles and standards across the codebase. There's been efforts to standardize our coding style, we have an official styleguide that isn't maintained as closely as it should... We still have some work in front of us.
However, in the last ~year or so, there's been a huge push towards incrementally improving the situation. As part of this we've been blocking PRs that don't add enough comments, or don't improve the files that they touch.
While looking at `Hasura.GraphQL.Analyse`, it became apparent that this file did not meet the engineering standards that I would expect to see addressed during a code review. Some ways in which I think it falls short:
- lack of documentation
- no clear distinction between public / internal components
- "unidiomatic" Haskell code (such as using `Either Result Error`)
While there's no problem with a file looking like this during development, those issues should have been caught at review time. The fact that they weren't indicates a problem in our process that we will need to address: code quality and maintainability is paramount, and we all need to do our part.
### Description
This PR rewrites all of `Hasura.GraphQL.Analyze`, and adapts `Hasura.Server.OpenAPI` accordingly where needed. I've attempted to clarify names and add documentation based on my understanding of the code, and to clean what was unused (such as field variables). I don't think this PR is good enough as is, and I welcome criticism where I got my comments wrong / am happy to help y'all add more.
This PR makes one small change in the way error messages are reported (and adjusts the corresponding test accordingly); each error message is now prefixed with the path within the selection set:
```
⚠️ $.test.foo.bar.baz.mizpelled: field 'mizpelled' not found in object 'Baz'
```
### Note
This PR is currently **on top of #3962**. You can preview the changes in isolation by [diffing the branches](https://github.com/hasura/graphql-engine-mono/compare/nicuveo/clean-rest-endpoint-inconsistency-check..nicuveo/rewrite-analysis).
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3963
Co-authored-by: paritosh-08 <85472423+paritosh-08@users.noreply.github.com>
GitOrigin-RevId: 5ec38e0e753f0c12096a350db0737658495e2f15
During the "generalization" of the code, we removed the [generated instances](9d63187803 (diff-7b8382ab20e441fa214586be491eb6f7ca904d8b20ed97894c16a339be45219aL72)) of `Eq` and `Hashable` in favour of manually written ones, because for a time we were struggling with `AnyBackend`.
In the process, we lost one constructor, `MOEndpoint`. It's unlikely to have ever been an issue, since duplicate endpoints are unlikely, but it is nonetheless wrong.
This PR simply goes back to default derived instances, now that we can, fixing the problem and making the code simpler.
---
However, after filing this PR, I realized **it broke rest endpoint tests**. Upon closer inspection, it turns out that while we had proper checks in place, because of this bug we were actually failing _differently_ during metadata checks. This PR actually improves error messages for invalid endpoint configurations?! 🙀
This is a tiny bit scary. ^^'
https://github.com/hasura/graphql-engine-mono/pull/1762
GitOrigin-RevId: c4897d1f3ae92d18c44c87d2f58258c66f716686
Previously invalid REST endpoints would throw errors during schema cache build.
This PR changes the validation to instead add to the inconsistent metadata objects in order to allow use of `allow_inconsistent_metadata` with inconsistent REST endpoints.
All non-fatal endpoint definition errors are returned as inconsistent metadata warnings/errors depending on the use of `allow_inconsistent_metadata`. The endpoints with issues are then created and return informational runtime errors when they are called.
Console impact when creating endpoints is that error messages now refer to metadata inconsistencies rather than REST feature at the top level:
<img width="969" alt="image" src="https://user-images.githubusercontent.com/92299/110258597-8336fa00-7ff7-11eb-872c-bfca945aa0e8.png">
Note: Conflicting endpoints generate one error per conflicting set of endpoints due to the implementation of `groupInconsistentMetadataById` and `imObjectIds`. This is done to ensure that error messages are terse, but may pose errors if there are some assumptions made surrounding `imObjectIds`.
Related to https://github.com/hasura/graphql-engine-mono/pull/473 (Allow Inconsistent Metadata (v2) #473 (Merged))
---
### Kodiak commit message
Changes the validation to use inconsistent metadata objects for REST endpoint issues.
#### Commit title
Inconsistent metadata for REST endpoints
GitOrigin-RevId: b9de971208e9bb0a319c57df8dace44cb115ff66
Resolves Issues:
* https://github.com/hasura/graphql-engine-mono/issues/658 - Invalid Slashes
* https://github.com/hasura/graphql-engine-mono/issues/628 - Subscriptions
Implementation:
* Moved some logic from Endpoint.hs to allow reuse of splitting url into PathSegments.
* Additional validation steps alongside checking for overlapping routes
* Logging potential misuse of GET for mutations
Future Work:
* [ ] GET is allowed for mutations (Ignore/Log warning for Now)
* [ ] Add to scInconsistentObjs rather than throwing error
* Add information to scInconsistentObjs instead of raising errors directly.
TODO:
* [x] Duplicate variable segments with the same name in the location should not be allowed
* [x] We should throw an error on trailing and leading slashes and URLs which contain empty segments
* [x] Endpoints can be created using subscriptions. But the error only shows at the time of the query
* [x] Tests
---
### Kodiak commit message
Prohibit Invalid slashes, duplicate variables, subscriptions for REST endpoints.
GitOrigin-RevId: 86c0d4af97984c8afd02699e6071e9c1658710b8
