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chore(rust): add circular reference detection and Box<T> wrapping for recursive types #10794

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Merged
iamnamananand996 merged 6 commits into from
Nov 25, 2025
Merged

chore(rust): add circular reference detection and Box<T> wrapping for recursive types #10794

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2ba01a8
chore(rust): add support for circular references
iamnamananand996 Nov 21, 2025
abd081b
chore: update seeds
iamnamananand996 Nov 21, 2025
2870482
chore: bump version
iamnamananand996 Nov 25, 2025
e96aa82
chore: bump version
iamnamananand996 Nov 25, 2025
0351cb7
chore: bump version
iamnamananand996 Nov 25, 2025
05618b3
fix changelog
iamnamananand996 Nov 25, 2025
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70 changes: 48 additions & 22 deletions generators/rust/base/src/context/AbstractRustGeneratorContext.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@ import {
escapeRustKeyword,
escapeRustReservedType,
generateDefaultCrateName,
RustCycleDetector,
validateAndSanitizeCrateName
} from "../utils";

Expand All @@ -28,6 +29,11 @@ export abstract class AbstractRustGeneratorContext<
) {
super(config, generatorNotificationService);

// Detect illegal recursive type cycles before any generation
// This will throw an error if the schema has cycles that cannot be represented in Rust
const cycleDetector = new RustCycleDetector(ir);
cycleDetector.detectIllegalCycles();

// Extract publish config from output mode
config.output.mode._visit<void>({
github: (github) => {
Expand Down Expand Up @@ -148,8 +154,11 @@ export abstract class AbstractRustGeneratorContext<
* Check if IR uses a specific primitive type
*/
private irUsesType(typeName: "DATE_TIME" | "DATE" | "UUID" | "BIG_INTEGER"): boolean {
// Use a visited set to prevent infinite recursion on circular types
const visited = new Set<string>();

for (const typeDecl of Object.values(this.ir.types)) {
if (this.typeShapeUsesBuiltin(typeDecl.shape, typeName)) {
if (this.typeShapeUsesBuiltin(typeDecl.shape, typeName, visited)) {
return true;
}
}
Expand All @@ -159,12 +168,12 @@ export abstract class AbstractRustGeneratorContext<
if (endpoint.requestBody != null) {
if (endpoint.requestBody.type === "inlinedRequestBody") {
for (const property of endpoint.requestBody.properties) {
if (this.typeReferenceUsesBuiltin(property.valueType, typeName)) {
if (this.typeReferenceUsesBuiltin(property.valueType, typeName, visited)) {
return true;
}
}
} else if (endpoint.requestBody.type === "reference") {
if (this.typeReferenceUsesBuiltin(endpoint.requestBody.requestBodyType, typeName)) {
if (this.typeReferenceUsesBuiltin(endpoint.requestBody.requestBodyType, typeName, visited)) {
return true;
}
}
Expand All @@ -175,9 +184,9 @@ export abstract class AbstractRustGeneratorContext<
json: (json: FernIr.JsonResponse) => {
return json._visit({
response: (response: FernIr.JsonResponseBody) =>
this.typeReferenceUsesBuiltin(response.responseBodyType, typeName),
this.typeReferenceUsesBuiltin(response.responseBodyType, typeName, visited),
nestedPropertyAsResponse: (nested: FernIr.JsonResponseBodyWithProperty) =>
this.typeReferenceUsesBuiltin(nested.responseBodyType, typeName),
this.typeReferenceUsesBuiltin(nested.responseBodyType, typeName, visited),
_other: () => false
});
},
Expand All @@ -194,19 +203,19 @@ export abstract class AbstractRustGeneratorContext<
}

for (const param of endpoint.queryParameters) {
if (this.typeReferenceUsesBuiltin(param.valueType, typeName)) {
if (this.typeReferenceUsesBuiltin(param.valueType, typeName, visited)) {
return true;
}
}

for (const param of endpoint.pathParameters) {
if (this.typeReferenceUsesBuiltin(param.valueType, typeName)) {
if (this.typeReferenceUsesBuiltin(param.valueType, typeName, visited)) {
return true;
}
}

for (const header of endpoint.headers) {
if (this.typeReferenceUsesBuiltin(header.valueType, typeName)) {
if (this.typeReferenceUsesBuiltin(header.valueType, typeName, visited)) {
return true;
}
}
Expand All @@ -218,14 +227,16 @@ export abstract class AbstractRustGeneratorContext<

/**
* Check if a type shape uses a specific builtin type
* @param visited Set of type IDs already visited to prevent infinite recursion
*/
private typeShapeUsesBuiltin(shape: FernIr.Type, typeName: string): boolean {
private typeShapeUsesBuiltin(shape: FernIr.Type, typeName: string, visited: Set<string>): boolean {
return shape._visit({
alias: (alias: FernIr.AliasTypeDeclaration) => this.typeReferenceUsesBuiltin(alias.aliasOf, typeName),
alias: (alias: FernIr.AliasTypeDeclaration) =>
this.typeReferenceUsesBuiltin(alias.aliasOf, typeName, visited),
enum: () => false,
object: (obj: FernIr.ObjectTypeDeclaration) => {
for (const property of obj.properties) {
if (this.typeReferenceUsesBuiltin(property.valueType, typeName)) {
if (this.typeReferenceUsesBuiltin(property.valueType, typeName, visited)) {
return true;
}
}
Expand All @@ -235,11 +246,15 @@ export abstract class AbstractRustGeneratorContext<
for (const variant of union.types) {
const usesBuiltin = variant.shape._visit({
singleProperty: (property: FernIr.SingleUnionTypeProperty) =>
this.typeReferenceUsesBuiltin(property.type, typeName),
this.typeReferenceUsesBuiltin(property.type, typeName, visited),
samePropertiesAsObject: (declaredType: FernIr.DeclaredTypeName) => {
// Prevent infinite recursion by checking if we've visited this type
if (visited.has(declaredType.typeId)) {
return false;
}
const typeDecl = this.ir.types[declaredType.typeId];
if (typeDecl) {
return this.typeShapeUsesBuiltin(typeDecl.shape, typeName);
return this.typeShapeUsesBuiltin(typeDecl.shape, typeName, visited);
}
return false;
},
Expand All @@ -254,7 +269,7 @@ export abstract class AbstractRustGeneratorContext<
},
undiscriminatedUnion: (union: FernIr.UndiscriminatedUnionTypeDeclaration) => {
for (const member of union.members) {
if (this.typeReferenceUsesBuiltin(member.type, typeName)) {
if (this.typeReferenceUsesBuiltin(member.type, typeName, visited)) {
return true;
}
}
Expand All @@ -266,29 +281,40 @@ export abstract class AbstractRustGeneratorContext<

/**
* Check if a type reference uses a specific builtin type
* @param visited Set of type IDs already visited to prevent infinite recursion
*/
private typeReferenceUsesBuiltin(typeRef: FernIr.TypeReference, typeName: string): boolean {
private typeReferenceUsesBuiltin(typeRef: FernIr.TypeReference, typeName: string, visited: Set<string>): boolean {
return typeRef._visit({
primitive: (primitive: FernIr.PrimitiveType) => {
return primitive.v1 === typeName;
},
container: (container: FernIr.ContainerType) => {
return container._visit({
list: (list: FernIr.TypeReference) => this.typeReferenceUsesBuiltin(list, typeName),
set: (set: FernIr.TypeReference) => this.typeReferenceUsesBuiltin(set, typeName),
optional: (optional: FernIr.TypeReference) => this.typeReferenceUsesBuiltin(optional, typeName),
nullable: (nullable: FernIr.TypeReference) => this.typeReferenceUsesBuiltin(nullable, typeName),
list: (list: FernIr.TypeReference) => this.typeReferenceUsesBuiltin(list, typeName, visited),
set: (set: FernIr.TypeReference) => this.typeReferenceUsesBuiltin(set, typeName, visited),
optional: (optional: FernIr.TypeReference) =>
this.typeReferenceUsesBuiltin(optional, typeName, visited),
nullable: (nullable: FernIr.TypeReference) =>
this.typeReferenceUsesBuiltin(nullable, typeName, visited),
map: (map: FernIr.MapType) =>
this.typeReferenceUsesBuiltin(map.keyType, typeName) ||
this.typeReferenceUsesBuiltin(map.valueType, typeName),
this.typeReferenceUsesBuiltin(map.keyType, typeName, visited) ||
this.typeReferenceUsesBuiltin(map.valueType, typeName, visited),
literal: () => false,
_other: () => false
});
},
named: (named: FernIr.NamedType) => {
// Prevent infinite recursion by checking if we've already visited this type
if (visited.has(named.typeId)) {
return false;
}

// Mark this type as visited
visited.add(named.typeId);

const typeDecl = this.ir.types[named.typeId];
if (typeDecl) {
return this.typeShapeUsesBuiltin(typeDecl.shape, typeName);
return this.typeShapeUsesBuiltin(typeDecl.shape, typeName, visited);
}
return false;
},
Expand Down
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