graphql-engine/server/src-lib/Hasura/Base
Samir Talwar eab4f75212 An ErrorMessage type, to encapsulate.
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
2022-07-18 20:27:06 +00:00
..
Error.hs server: Handle special characters in parseJSONPath and encodeJSONPath. 2022-07-05 15:53:45 +00:00
ErrorMessage.hs An ErrorMessage type, to encapsulate. 2022-07-18 20:27:06 +00:00
ErrorValue.hs An ErrorMessage type, to encapsulate. 2022-07-18 20:27:06 +00:00
Instances.hs server: more GHC 9.2 changes compatible with 8.10 (#3550) 2022-07-07 16:51:18 +00:00
README.md server: introduce Hasura.Base (take 2) 2021-05-11 15:19:33 +00:00
ToErrorValue.hs An ErrorMessage type, to encapsulate. 2022-07-18 20:27:06 +00:00

Hasura.Base

This sub-module contains all code that has no internal dependency except for our custom Prelude: either libraries that are too Hasura-specific to be moved to a dedicated folder outside of Hasura, or type definitions that are used throughout the entire codebase.