Redesign #[graphql_scalar] macro (#1014, #1000)

- support generic scalars
- make it applicable to type aliases and struct/enums/unions

Author: ilslv

docs/book/content/types/scalars.md

@@ -1,21 +1,21 @@
-error[E0119]: conflicting implementations of trait `<CharacterValueEnum<ObjA, ObjA> as juniper::GraphQLInterface<__S>>::mark::_::{closure#0}::MutuallyExclusive` for type `ObjA`
+error[E0119]: conflicting implementations of trait `std::convert::From<ObjA>` for type `CharacterValueEnum<ObjA, ObjA>`
   --> fail/interface/implementers_duplicate_ugly.rs:11:1
    |
 11 | #[graphql_interface(for = [ObjA, ObjAlias])]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    | |
    | first implementation here
-   | conflicting implementation for `ObjA`
+   | conflicting implementation for `CharacterValueEnum<ObjA, ObjA>`
    |
-   = note: this error originates in the macro `::juniper::sa::assert_type_ne_all` (in Nightly builds, run with -Z macro-backtrace for more info)
+   = note: this error originates in the attribute macro `graphql_interface` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error[E0119]: conflicting implementations of trait `std::convert::From<ObjA>` for type `CharacterValueEnum<ObjA, ObjA>`
+error[E0119]: conflicting implementations of trait `<CharacterValueEnum<ObjA, ObjA> as juniper::GraphQLInterface<__S>>::mark::_::{closure#0}::MutuallyExclusive` for type `ObjA`
   --> fail/interface/implementers_duplicate_ugly.rs:11:1
    |
 11 | #[graphql_interface(for = [ObjA, ObjAlias])]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    | |
    | first implementation here
-   | conflicting implementation for `CharacterValueEnum<ObjA, ObjA>`
+   | conflicting implementation for `ObjA`
    |
-   = note: this error originates in the attribute macro `graphql_interface` (in Nightly builds, run with -Z macro-backtrace for more info)
+   = note: this error originates in the macro `::juniper::sa::assert_type_ne_all` (in Nightly builds, run with -Z macro-backtrace for more info)

integration_tests/codegen_fail/fail/interface/implementers_duplicate_ugly.stderr

@@ -0,0 +1,16 @@
+use juniper::{graphql_scalar, InputValue, ScalarValue, Value};
+
+#[graphql_scalar(specified_by_url = "not an url", parse_token(i32))]
+struct ScalarSpecifiedByUrl(i32);
+
+impl ScalarSpecifiedByUrl {
+    fn to_output<S: ScalarValue>(&self) -> Value<S> {
+        Value::scalar(0)
+    }
+
+    fn from_input<S: ScalarValue>(_: &InputValue<S>) -> Result<Self, String> {
+        Ok(Self)
+    }
+}
+
+fn main() {}

integration_tests/codegen_fail/fail/scalar/derive_input/impl_invalid_url.rs

@@ -0,0 +1,17 @@
+error: Invalid URL: relative URL without a base
+ --> fail/scalar/derive_input/impl_invalid_url.rs:3:37
+  |
+3 | #[graphql_scalar(specified_by_url = "not an url", parse_token(i32))]
+  |                                     ^^^^^^^^^^^^
+
+error[E0412]: cannot find type `ScalarSpecifiedByUrl` in this scope
+ --> fail/scalar/derive_input/impl_invalid_url.rs:6:6
+  |
+6 | impl ScalarSpecifiedByUrl {
+  |      ^^^^^^^^^^^^^^^^^^^^ not found in this scope
+
+error: the `Self` constructor can only be used with tuple or unit structs
+  --> fail/scalar/derive_input/impl_invalid_url.rs:12:12
+   |
+12 |         Ok(Self)
+   |            ^^^^

integration_tests/codegen_fail/fail/scalar/derive_input/impl_invalid_url.stderr

@@ -0,0 +1,26 @@
+use juniper::{graphql_scalar, InputValue, ScalarValue, Value};
+
+struct ScalarSpecifiedByUrl;
+
+#[graphql_scalar(
+    specified_by_url = "not an url",
+    with = scalar,
+    parse_token(i32),
+)]
+type Scalar = ScalarSpecifiedByUrl;
+
+mod scalar {
+    use super::*;
+
+    pub(super) fn to_output<S: ScalarValue>(_: &ScalarSpecifiedByUrl) -> Value<S> {
+        Value::scalar(0)
+    }
+
+    pub(super) fn from_input<S: ScalarValue>(
+        _: &InputValue<S>,
+    ) -> Result<ScalarSpecifiedByUrl, String> {
+        Ok(ScalarSpecifiedByUrl)
+    }
+}
+
+fn main() {}

integration_tests/codegen_fail/fail/scalar/derive_invalid_url.rs

@@ -0,0 +1,5 @@
+error: Invalid URL: relative URL without a base
+ --> fail/scalar/type_alias/impl_invalid_url.rs:6:24
+  |
+6 |     specified_by_url = "not an url",
+  |                        ^^^^^^^^^^^^

integration_tests/codegen_fail/fail/scalar/derive_invalid_url.stderr

@@ -0,0 +1,14 @@
+use juniper::{graphql_scalar, Value};
+
+struct Scalar;
+
+#[graphql_scalar(to_output_with = Scalar::to_output)]
+type CustomScalar = Scalar;
+
+impl Scalar {
+    fn to_output(&self) -> Value {
+        Value::scalar(0)
+    }
+}
+
+fn main() {}

integration_tests/codegen_fail/fail/scalar/impl_invalid_url.rs

@@ -0,0 +1,5 @@
+error: GraphQL scalar all custom resolvers have to be provided via `with` or combination of `to_output_with`, `from_input_with`, `parse_token_with` attributes
+ --> fail/scalar/type_alias/impl_with_not_all_resolvers.rs:6:1
+  |
+6 | type CustomScalar = Scalar;
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^

integration_tests/codegen_fail/fail/scalar/impl_invalid_url.stderr

@@ -0,0 +1,8 @@
+use juniper::graphql_scalar;
+
+struct Scalar;
+
+#[graphql_scalar]
+type CustomScalar = Scalar;
+
+fn main() {}

integration_tests/codegen_fail/fail/scalar/type_alias/impl_invalid_url.rs

@@ -0,0 +1,5 @@
+error: GraphQL scalar all custom resolvers have to be provided via `with` or combination of `to_output_with`, `from_input_with`, `parse_token_with` attributes
+ --> fail/scalar/type_alias/impl_without_resolvers.rs:6:1
+  |
+6 | type CustomScalar = Scalar;
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^

integration_tests/codegen_fail/fail/scalar/type_alias/impl_invalid_url.stderr

@@ -5,6 +5,7 @@ edition = "2018"
 publish = false
 
 [dependencies]
+chrono = "0.4"
 derive_more = "0.99"
 futures = "0.3"
 juniper = { path = "../../juniper" }