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Polishing in SchemaMappingInspector

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rstoyanchev
2023-04-20 15:46:05 +01:00
parent d933828a23
commit fb6a225193
3 changed files with 50 additions and 38 deletions
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spring-graphql-docs/src/docs/asciidoc/index.adoc
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@@ -414,8 +414,8 @@ Spring for GraphQL defines the `SelfDescribingDataFetcher` interface to allow a
`DataFetcher` to expose return type information. All Spring `DataFetcher` implementations
implement this interface. That includes those for <<controllers>>, and those for
<<data.querydsl>> and <<data.querybyexample>> Spring Data repositories. For annotated
controllers, the return type is derived from the declared return type on `@SchemaMapping`
methods.
controllers, the return type is derived from the declared return type on a
`@SchemaMapping` method.
On startup, Spring for GraphQL inspects all schema fields, `DataFetcher` registrations,
and the properties of Java objects returned from `DataFetcher` implementations in order
@@ -432,18 +432,23 @@ GraphQL schema inspection:
<1> List of schema fields and their source types that are not mapped
<2> List of schema types that are skipped, as explained next
There are limits to what schema mappings inspection can do, in particular when there is insufficient Java
type information. This is the case if an annotated controller method returns
`java.lang.Object` such as for a `union` type, or if a `DataFetcher` does not implement
`SelfDescribingDataFetcher`. If a schema type is skipped, its name is listed as such in
the report, and a DEBUG message is logged to provide a reason for why it was skipped.
There are limits to what schema mappings inspection can do, in particular when there is
insufficient Java type information. This is the case if an annotated controller method is
declared to return `java.lang.Object`, or if the return type has an unspecified generic
parameter such as `List<?>`, or if the `DataFetcher` does not implement
`SelfDescribingDataFetcher` and the return type is not even known. In such cases, the
Java object type structure remains unknown, and the schema type is listed as skipped in
the resulting report. For every skipped type, a DEBUG message is logged to indicate why
it was skipped.
For schema `interface` types, the inspection currently checks only fields declared
directly on the interface against properties of the Java return type declared by the
`DataFetcher`. Additional fields on concrete implementations are not inspected, as there
is insufficient information about what Java types may be returned at runtime. This could
be improved in a future release to extend inspection to schema `interface` implementing
types to look for a match among subtypes of the declared Java return type.
Schema union types are always skipped because there is no way for a controller method to
declare such a return type in Java, and the Java type structure is unknown.
Schema interface types are supported only as far as fields declared directly, which are
compared against properties on the Java type declared by a `SelfDescribingDataFetcher`.
Additional fields on concrete implementations are not inspected. This could be improved
in a future release to also inspect scheam `interface` implementation types and to try
to find a match among subtypes of the declared Java return type.
[[execution.graphqlsource.operation-caching]]