[Vertex AI] Add minItems and maxItems to Schema (#14671)

Author: andrewheard

FirebaseVertexAI/CHANGELOG.md

@@ -6,6 +6,8 @@
   Note: This feature is in Public Preview and relies on experimental models,
   which means that it is not subject to any SLA or deprecation policy and could
   change in backwards-incompatible ways.
+- [added] Added support for specifying the minimum and maximum number of items
+  (`minItems` / `maxItems`) to generate in an array `Schema`. (#14671)
 
 # 11.11.0
 - [added] Emits a warning when attempting to use an incompatible model with

FirebaseVertexAI/Sources/Types/Public/Schema.swift

@@ -80,6 +80,12 @@ public final class Schema: Sendable {
   /// Schema of the elements of type `"ARRAY"`.
   public let items: Schema?
 
+  /// The minimum number of items (elements) in a schema of type `"ARRAY"`.
+  public let minItems: Int?
+
+  /// The maximum number of items (elements) in a schema of type `"ARRAY"`.
+  public let maxItems: Int?
+
   /// Properties of type `"OBJECT"`.
   public let properties: [String: Schema]?
 
@@ -88,13 +94,16 @@ public final class Schema: Sendable {
 
   required init(type: DataType, format: String? = nil, description: String? = nil,
                 nullable: Bool = false, enumValues: [String]? = nil, items: Schema? = nil,
+                minItems: Int? = nil, maxItems: Int? = nil,
                 properties: [String: Schema]? = nil, requiredProperties: [String]? = nil) {
     dataType = type
     self.format = format
     self.description = description
     self.nullable = nullable
     self.enumValues = enumValues
     self.items = items
+    self.minItems = minItems
+    self.maxItems = maxItems
     self.properties = properties
     self.requiredProperties = requiredProperties
   }
@@ -256,12 +265,23 @@ public final class Schema: Sendable {
   /// - Parameters:
   ///   - items: The `Schema` of the elements that the array will hold.
   ///   - description: An optional description of what the array should contain or represent; may
-  ///   use Markdown format.
+  ///     use Markdown format.
   ///   - nullable: If `true`, instructs the model that it may return `null` instead of an array;
-  ///   defaults to `false`, enforcing that an array is returned.
-  public static func array(items: Schema, description: String? = nil,
-                           nullable: Bool = false) -> Schema {
-    return self.init(type: .array, description: description, nullable: nullable, items: items)
+  ///     defaults to `false`, enforcing that an array is returned.
+  ///   - minItems: Instructs the model to produce at least the specified minimum number of elements
+  ///     in the array; defaults to `nil`, meaning any number.
+  ///   - maxItems: Instructs the model to produce at most the specified maximum number of elements
+  ///     in the array.
+  public static func array(items: Schema, description: String? = nil, nullable: Bool = false,
+                           minItems: Int? = nil, maxItems: Int? = nil) -> Schema {
+    return self.init(
+      type: .array,
+      description: description,
+      nullable: nullable,
+      items: items,
+      minItems: minItems,
+      maxItems: maxItems
+    )
   }
 
   /// Returns a `Schema` representing an object.
@@ -327,6 +347,8 @@ extension Schema: Encodable {
     case nullable
     case enumValues = "enum"
     case items
+    case minItems
+    case maxItems
     case properties
     case requiredProperties = "required"
   }

FirebaseVertexAI/Tests/Unit/GenerationConfigTests.swift

@@ -104,6 +104,7 @@ final class GenerationConfigTests: XCTestCase {
       responseMIMEType: mimeType,
       responseSchema: .object(properties: [
         "firstName": .string(),
+        "middleNames": .array(items: .string(), minItems: 0, maxItems: 3),
         "lastName": .string(),
         "age": .integer(),
       ])
@@ -129,12 +130,23 @@ final class GenerationConfigTests: XCTestCase {
           "lastName" : {
             "nullable" : false,
             "type" : "STRING"
+          },
+          "middleNames" : {
+            "items" : {
+              "nullable" : false,
+              "type" : "STRING"
+            },
+            "maxItems" : 3,
+            "minItems" : 0,
+            "nullable" : false,
+            "type" : "ARRAY"
           }
         },
         "required" : [
           "age",
           "firstName",
-          "lastName"
+          "lastName",
+          "middleNames"
         ],
         "type" : "OBJECT"
       }