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Backport 26.1: Reject cyclical SDL directive definitions #4451

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Merged
andimarek merged 2 commits into from
Aug 23, 2026
Merged

Backport 26.1: Reject cyclical SDL directive definitions #4451

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0b5486d
Reject indirect directive definition cycles
andimarek May 18, 2026
9158901
Simplify directive cycle detection
andimarek Aug 23, 2026
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77 changes: 76 additions & 1 deletion src/main/java/graphql/schema/idl/SchemaTypeDirectivesChecker.java
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Original file line number Diff line number Diff line change
Expand Up @@ -30,11 +30,16 @@
import graphql.schema.idl.errors.MissingTypeError;
import graphql.schema.idl.errors.NotAnInputTypeError;

import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;

import static graphql.Assert.assertNotNull;
import static graphql.introspection.Introspection.DirectiveLocation.ARGUMENT_DEFINITION;
import static graphql.introspection.Introspection.DirectiveLocation.ENUM;
import static graphql.introspection.Introspection.DirectiveLocation.ENUM_VALUE;
Expand Down Expand Up @@ -182,6 +187,9 @@ private static boolean isNoNullArgWithoutDefaultValue(InputValueDefinition defin
}

private void commonCheck(Collection<DirectiveDefinition> directiveDefinitions, List<GraphQLError> errors) {
List<DirectiveDefinition> directiveDefinitionsList = new ArrayList<>(directiveDefinitions);
Map<String, DirectiveDefinition> directiveDefinitionsByName = getByName(directiveDefinitionsList, DirectiveDefinition::getName, mergeFirst());

directiveDefinitions.forEach(directiveDefinition -> {
assertTypeName(directiveDefinition, errors);
directiveDefinition.getInputValueDefinitions().forEach(inputValueDefinition -> {
Expand All @@ -192,6 +200,73 @@ private void commonCheck(Collection<DirectiveDefinition> directiveDefinitions, L
}
});
});
checkIndirectDirectiveCycles(directiveDefinitionsByName, errors);
}

private static Map<String, InputValueDefinition> directiveReferences(DirectiveDefinition directiveDefinition) {
Map<String, InputValueDefinition> result = new LinkedHashMap<>();
for (InputValueDefinition inputValueDefinition : directiveDefinition.getInputValueDefinitions()) {
recordDirectiveReferences(directiveDefinition, result, inputValueDefinition);
}
return result;
}

private static void recordDirectiveReferences(DirectiveDefinition directiveDefinition,
Map<String, InputValueDefinition> result,
InputValueDefinition inputValueDefinition) {
for (Directive directive : inputValueDefinition.getDirectives()) {
if (directive.getName().equals(directiveDefinition.getName())) {
continue;
}
result.putIfAbsent(directive.getName(), inputValueDefinition);
}
}

private static void checkIndirectDirectiveCycles(
Map<String, DirectiveDefinition> directiveDefinitionsByName,
List<GraphQLError> errors) {
Set<String> checked = new LinkedHashSet<>();
// Insertion order records the active recursion path for the error message.
LinkedHashSet<String> currentPath = new LinkedHashSet<>();
for (DirectiveDefinition directiveDefinition : directiveDefinitionsByName.values()) {
checkDirectiveReferencesForCycles(directiveDefinition, directiveDefinitionsByName, checked, currentPath, errors);
}
}

private static void checkDirectiveReferencesForCycles(DirectiveDefinition directiveDefinition,
Map<String, DirectiveDefinition> directiveDefinitionsByName,
Set<String> checked,
LinkedHashSet<String> currentPath,
List<GraphQLError> errors) {
String directiveName = directiveDefinition.getName();
if (checked.contains(directiveName)) {
return;
}

currentPath.add(directiveName);
for (Map.Entry<String, InputValueDefinition> reference : directiveReferences(directiveDefinition).entrySet()) {
String referencedDirectiveName = reference.getKey();
if (currentPath.contains(referencedDirectiveName)) {
DirectiveDefinition repeatedDirective = assertNotNull(directiveDefinitionsByName.get(referencedDirectiveName));
String cyclePath = directiveCyclePath(referencedDirectiveName, currentPath);
errors.add(new DirectiveIllegalReferenceError(repeatedDirective, reference.getValue(), cyclePath));
continue;
}
DirectiveDefinition referencedDirective = directiveDefinitionsByName.get(referencedDirectiveName);
if (referencedDirective != null) {
checkDirectiveReferencesForCycles(referencedDirective, directiveDefinitionsByName, checked, currentPath, errors);
}
}
currentPath.remove(directiveName);
checked.add(directiveName);
}

private static String directiveCyclePath(String repeatedDirectiveName, LinkedHashSet<String> currentPath) {
List<String> pathList = new ArrayList<>(currentPath);
int cycleStart = pathList.indexOf(repeatedDirectiveName);
List<String> cyclePath = new ArrayList<>(pathList.subList(cycleStart, pathList.size()));
cyclePath.add(repeatedDirectiveName);
return String.join(" -> ", cyclePath);
}

private static void assertTypeName(NamedNode<?> node, List<GraphQLError> errors) {
Expand Down Expand Up @@ -224,4 +299,4 @@ private static TypeDefinition<?> findTypeDefFromRegistry(String typeName, TypeDe
}
return typeRegistry.scalars().get(typeName);
}
}
}
9 changes: 8 additions & 1 deletion src/main/java/graphql/schema/idl/errors/DirectiveIllegalReferenceError.java
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Expand Up @@ -12,4 +12,11 @@ public DirectiveIllegalReferenceError(DirectiveDefinition directive, NamedNode l
directive.getName(), location.getName(), lineCol(location)
));
}
}

public DirectiveIllegalReferenceError(DirectiveDefinition directive, NamedNode location, String cyclePath) {
super(directive,
String.format("'%s' must not reference itself via directive cycle '%s' on '%s''%s'",
directive.getName(), cyclePath, location.getName(), lineCol(location)
));
}
}
22 changes: 22 additions & 0 deletions src/test/groovy/graphql/schema/idl/SchemaGeneratorTest.groovy
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@ import graphql.schema.GraphQLType
import graphql.schema.GraphQLTypeUtil
import graphql.schema.GraphQLUnionType
import graphql.schema.GraphqlTypeComparatorRegistry
import graphql.schema.idl.errors.DirectiveIllegalReferenceError
import graphql.schema.idl.errors.NotAnInputTypeError
import graphql.schema.idl.errors.NotAnOutputTypeError
import graphql.schema.idl.errors.SchemaProblem
Expand Down Expand Up @@ -2270,6 +2271,27 @@ class SchemaGeneratorTest extends Specification {
schema != null
}

def "#4201 indirect cyclical directive definitions are rejected without stack overflow"() {
given:
def registry = new SchemaParser().parse('''
directive @foo(x: Int @bar(y: 1)) on FIELD_DEFINITION | ARGUMENT_DEFINITION
directive @bar(y: Int @foo(x: 2)) on FIELD_DEFINITION | ARGUMENT_DEFINITION

type Query {
field: String @foo(x: 10) @bar(y: 20)
}
''')

when:
UnExecutableSchemaGenerator.makeUnExecutableSchema(registry)

then:
def e = thrown(SchemaProblem)
e.errors.size() == 1
e.errors.get(0) instanceof DirectiveIllegalReferenceError
e.errors.get(0).getMessage().contains("'foo' must not reference itself via directive cycle 'foo -> bar -> foo'")
}

def "code registry default data fetcher is respected"() {
def sdl = '''
type Query {
Expand Down
60 changes: 60 additions & 0 deletions src/test/groovy/graphql/schema/idl/SchemaTypeDirectivesCheckerTest.groovy
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Expand Up @@ -232,6 +232,66 @@ class SchemaTypeDirectivesCheckerTest extends Specification {
errors.get(0).getMessage() == "'invalidExample' must not reference itself on 'arg''[@2:39]'"
}

def "directive must not indirectly reference itself - #name"() {
given:
def registry = parse(spec)
def errors = []

when:
new SchemaTypeDirectivesChecker(registry, RuntimeWiring.newRuntimeWiring().build()).checkTypeDirectives(errors)

then:
errors.size() == 1
errors.get(0) instanceof DirectiveIllegalReferenceError
errors.get(0).getMessage().contains(cycleMessage)

where:
name << ["two directives", "three directives"]
spec << [
'''
directive @foo(arg: String @bar) on ARGUMENT_DEFINITION
directive @bar(arg: String @foo) on ARGUMENT_DEFINITION

type Query {
f1 : String
}
''',
'''
directive @dirA(x: Int @dirB(y: 1)) on ARGUMENT_DEFINITION
directive @dirB(y: Int @dirC(z: 2)) on ARGUMENT_DEFINITION
directive @dirC(z: Int @dirA(x: 3)) on ARGUMENT_DEFINITION

type Query {
f1 : String
}
'''
]
cycleMessage << [
"'foo' must not reference itself via directive cycle 'foo -> bar -> foo'",
"'dirA' must not reference itself via directive cycle 'dirA -> dirB -> dirC -> dirA'"
]
}

def "acyclic directive references are allowed"() {
given:
def registry = parse('''
directive @foo(arg: String @bar) on ARGUMENT_DEFINITION
directive @bar(arg: String @baz) on ARGUMENT_DEFINITION
directive @baz on ARGUMENT_DEFINITION

type Query {
f1 : String
}
''')
def errors = []

when:
new SchemaTypeDirectivesChecker(registry, RuntimeWiring.newRuntimeWiring().build()).checkTypeDirectives(errors)

then:
errors.isEmpty()
}

def "directive must not begin with '__'"() {
given:
def spec = '''
Expand Down
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