Merge branch 'relay-id' into 0.159.0-plus-relay

.coveragerc

@@ -29,6 +29,9 @@ exclude_lines =
 
     @overload
 
+    # Those are not supposed to be hit
+    assert_never\(\w+\)
+
 ignore_errors = True
 
 omit =

RELEASE.md

@@ -0,0 +1,4 @@
+Release type: minor
+
+Initial relay spec implementation. For information on how to use
+it, check out the docs in here: https://strawberry.rocks/docs/guides/relay

docs/README.md

@@ -44,6 +44,7 @@
 - [Dealing with errors](./guides/errors.md)
 - [Federation](./guides/federation.md)
 - [Federation V1](./guides/federation-v1.md)
+- [Relay](./guides/relay.md)
 - [Custom extensions](./guides/custom-extensions.md)
 - [File upload](./guides/file-upload.md)
 - [Pagination](./guides/pagination/overview.md)

docs/errors/relay-wrong-annotation.md

@@ -0,0 +1,70 @@
+---
+title: Relay wrong annotation Error
+---
+
+# Relay wrong annotation error
+
+## Description
+
+This error is thrown when a field on a relay connection has a wrong
+type annotation. For example, the following code will throw this error:
+
+```python
+from typing import List
+
+import strawberry
+
+
+@strawberry.type
+class NonNodeSubclassType:
+    ...
+
+
+@strawberry.type
+class Query:
+    @strawberry.relay.connection
+    def some_connection(self) -> int:
+        ...
+
+    @strawberry.relay.connection
+    def some_other_connection(self) -> List[NonNodeSubclassType]:
+        ...
+```
+
+This happens because when defining a custom resolver for the connection,
+it expects the type annotation to be one of: `Iterable[<NodeType>]`,
+`Iterator[<NodeType>]`, `AsyncIterable[<NodeType>]` or `AsyncIterator[<NodeType]`
+
+## How to fix this error
+
+You can fix this error by annotating the connection custom resolver with
+one of the following possibilities:
+
+- `Iterable[<NodeType>]`
+- `Iterator[<NodeType>]`
+- `AsyncIterable[<NodeType>]`
+- `AsyncIterator[<NodeType]`
+
+For example:
+
+```python
+from typing import Iterable, List
+
+import strawberry
+
+
+@strawberry.type
+class NodeSubclassType(strawberry.relay.Node):
+    ...
+
+
+@strawberry.type
+class Query:
+    @strawberry.relay.connection
+    def some_connection(self) -> List[NodeSubclassType]:
+        ...
+
+    @strawberry.relay.connection
+    def some_other_connection(self) -> Iterable[NodeSubclassType]:
+        ...
+```

docs/errors/relay-wrong-node-resolver-annotation.md

@@ -0,0 +1,66 @@
+---
+title: Relay wrong annotation Error
+---
+
+# Relay wrong annotation error
+
+## Description
+
+This error is thrown when a field on a relay connection was defined with
+a `node_converter` that has the wrong type type annotation. For example,
+the following code will throw this error:
+
+```python
+from typing import Iterable
+
+import strawberry
+
+
+@strawberry.type
+class NonNodeSubclassType:
+    ...
+
+
+def node_converter(node_id: str) -> NonNodeSubclassType:
+    ...
+
+
+@strawberry.type
+class Query:
+    @strawberry.relay.connection(NonNodeSubclassType)
+    def some_connection(self) -> Iterable[str]:
+        ...
+```
+
+This happens because when defining a `node_converter`, it is expected
+to be a function that receives the iterable element as its single argument,
+and should return the correct strawberry `Node` implemented type.
+
+## How to fix this error
+
+You can fix this error by annotating the `node_converter` function to
+return the correct strawberry `Node` implemented type.
+
+For example:
+
+```python
+from typing import Iterable
+
+import strawberry
+
+
+@strawberry.type
+class NodeSubclassType(strawberry.relay.Node):
+    ...
+
+
+def node_converter(node_id: str) -> NodeSubclassType:
+    ...
+
+
+@strawberry.type
+class Query:
+    @strawberry.relay.connection(node_converter=node_converter)
+    def some_connection(self) -> Iterable[str]:
+        ...
+```

docs/guides/pagination/overview.md

@@ -117,6 +117,14 @@ need a reliable and consistent way to handle pagination.
 
 ### Cursor based pagination
 
+<Note>
+
+Strawberry provides a cursor based pagination implementing the
+[relay spec](https://relay.dev/docs/guides/graphql-server-specification/).
+You can read more about it in the [relay](./input-types) page.
+
+<Note/>
+
 Cursor based pagination, also known as keyset pagination, works by returning a pointer to a specific item in the dataset. On subsequent requests,
 the server returns results after the given pointer. This method addresses the drawbacks of using offset pagination, but does so by making certain trade offs: