NPE in CacheProvider caused by adding default values for variables

Hi @bbakerman @andimarek,

I implemented a CacheProvider:

public class CacheProvider implements PreparsedDocumentProvider {

    @Resource
    private Cache<String, PreparsedDocumentEntry> cache;

    @Override
    public PreparsedDocumentEntry getDocument(final ExecutionInput executionInput,
            final Function<ExecutionInput, PreparsedDocumentEntry> computeFunction) {

        final Function<String, PreparsedDocumentEntry> mapCompute = key -> {
            try {
                return computeFunction.apply(executionInput);
            } catch (Exception e) {
                throw new IllegalArgumentException(String.format("Failed to compute cache key for query: %s . variables: %s",
                        executionInput.getQuery(), executionInput.getVariables()));
            }
        };

        return cache.get(executionInput.getQuery(), mapCompute);
    }

}

I got a NPE when I call computeFunction.apply(executionInput) with this kind of queries:

query search($texte: String = "", $includetest: Boolean = true){
  search(query: $texte) {
	  test @include(if: $includetest){
	      ...testFragment
	  }
  }
}

Variables:

{
    "texte": "work"
}

If I add includetest in my variables, it works. Is it the expected behavior ?

Default variables 
Default values can also be assigned to the variables in the query by adding the default value after the type declaration.

query HeroNameAndFriends($episode: Episode = JEDI) {
  hero(episode: $episode) {
    name
    friends {
      name
    }
  }
}
When default values are provided for all variables, you can call the query without passing any variables. If any variables are passed as part of the variables dictionary, they will override the defaults.

Infos:

  <caffeine.version>2.8.6</caffeine.version>
  <graphql-java.version>15.0</graphql-java.version>

Thanks

[bbakerman]

eg

        Map<String, Object> inputVariables = executionInput.getVariables();
        List<VariableDefinition> variableDefinitions = operationDefinition.getVariableDefinitions();

        Map<String, Object> coercedVariables;
        try {
            coercedVariables = valuesResolver.coerceVariableValues(graphQLSchema, variableDefinitions, inputVariables);
        } catch (RuntimeException rte) {
            if (rte instanceof GraphQLError) {
                return completedFuture(new ExecutionResultImpl((GraphQLError) rte));
            }
            throw rte;
        }

This type of code.

The work around here is to define the conditional variables explicitly until this bug is fixed when using these instrumentions

[bbakerman]

I am able to reproduce this a bug

 def sdl = """ 
                type Query { foo : FooType }
                type FooType { bar : String }
                """
        def instrumentation = new ChainedInstrumentation([
                new MaxQueryComplexityInstrumentation(20),
                new MaxQueryDepthInstrumentation(20)
        ])
        def graphQL = TestUtil.graphQL(sdl)
                .instrumentation(instrumentation)
                .build()

        when:
        def er = graphQL.execute('''
            query withDefaults( $var : Boolean = true) {
                foo @include(if: $var) {
                    bar
                }
            }
        ''')

        then:
        er.errors.isEmpty()

java.lang.NullPointerException
	at graphql.execution.ConditionalNodes.getDirectiveResult(ConditionalNodes.java:39)
	at graphql.execution.ConditionalNodes.shouldInclude(ConditionalNodes.java:24)
	at graphql.analysis.NodeVisitorWithTypeTracking.visitField(NodeVisitorWithTypeTracking.java:173)
	at graphql.language.Field.accept(Field.java:191)
	at graphql.language.NodeTraverser$1.enter(NodeTraverser.java:61)
	at graphql.util.Traverser.traverse(Traverser.java:144)
	at graphql.language.NodeTraverser.doTraverse(NodeTraverser.java:149)
	at graphql.language.NodeTraverser.depthFirst(NodeTraverser.java:69)
	at graphql.analysis.QueryTraverser.visitImpl(QueryTraverser.java:178)
	at graphql.analysis.QueryTraverser.visitPostOrder(QueryTraverser.java:83)
	at graphql.analysis.MaxQueryComplexityInstrumentation.lambda$beginValidation$4(MaxQueryComplexityInstrumentation.java:88)
	at graphql.execution.instrumentation.SimpleInstrumentationContext.onCompleted(SimpleInstrumentationContext.java:48)
	at graphql.execution.instrumentation.ChainedInstrumentation$ChainedInstrumentationContext.lambda$onCompleted$1(ChainedInstrumentation.java:258)
	at java.util.ArrayList.forEach(ArrayList.java:1257)
	at java.util.Collections$UnmodifiableCollection.forEach(Collections.java:1080)
	at graphql.execution.instrumentation.ChainedInstrumentation$ChainedInstrumentationContext.onCompleted(ChainedInstrumentation.java:258)
	at graphql.GraphQL.validate(GraphQL.java:588)
	at graphql.GraphQL.parseAndValidate(GraphQL.java:550)
	at graphql.GraphQL.lambda$parseValidateAndExecute$5(GraphQL.java:519)
	at graphql.execution.preparsed.NoOpPreparsedDocumentProvider.getDocument(NoOpPreparsedDocumentProvider.java:15)
	at graphql.GraphQL.parseValidateAndExecute(GraphQL.java:521)
	at graphql.GraphQL.executeAsync(GraphQL.java:490)
	at graphql.GraphQL.execute(GraphQL.java:421)
	at graphql.GraphQL.execute(GraphQL.java:303)
	at graphql.execution.ConditionalNodesTest.can default conditional node values(ConditionalNodesTest.groovy:57)

It’s caused by ConditionalNodes being invoked BUT the variable coercer has not run yet to default the variables (which happens after parse/validate.

Both of these instrumentions call

        QueryTraverser queryTraverser = QueryTraverser.newQueryTraverser()
                .schema(executionContext.getGraphQLSchema())
                .document(executionContext.getDocument())
                .operationName(executionContext.getOperationDefinition().getName())
                .variables(executionContext.getVariables())
                .build();

we have to move the variable coercing code into this so that we can do the defaulting as required