Add foreignKeys experimental setting support

.code-samples.meilisearch.yaml

@@ -613,6 +613,22 @@ update_localized_attribute_settings_1: |-
   );
 reset_localized_attribute_settings_1: |-
   client.index("INDEX_NAME").resetLocalizedAttributesSettings();
+get_foreign_keys_setting_1: |-
+  client.index("INDEX_NAME").getForeignKeysSettings();
+update_foreign_keys_setting_1: |-
+  ForeignKey firstForeignKey = new ForeignKey();
+  firstForeignKey.setForeignIndexUid("authors");
+  firstForeignKey.setFieldName("author");
+
+  ForeignKey secondForeignKey = new ForeignKey();
+  secondForeignKey.setForeignIndexUid("authors");
+  secondForeignKey.setFieldName("related_authors");
+
+  client.index("books").updateForeignKeysSettings(
+    new ForeignKey[]{firstForeignKey, secondForeignKey}
+  );
+reset_foreign_keys_setting_1: |-
+  client.index("INDEX_NAME").resetForeignKeysSettings();
 export_post_1: |-
   Map<String, ExportIndexFilter> indexes = new HashMap<>();
   indexes.put("*", ExportIndexFilter.builder().overrideSettings(true).build());
@@ -639,4 +655,4 @@ webhooks_patch_1: |-
 
   Webhook updated_webhook = this.client.updateWebhook(webhook.getUuid(), webhookReq2);
 webhooks_delete_1: |-
-  this.client.deleteWebhook("WEBHOOK_UUID");
+  this.client.deleteWebhook("WEBHOOK_UUID");

build.gradle

@@ -109,13 +109,15 @@ jacocoTestReport {
 }
 
 tasks.register('integrationTest', Test) {
-	useJUnitPlatform {
-		includeTags 'integration'
-	}
-	testLogging {
-		events 'passed', 'skipped', 'failed'
-		showStandardStreams = System.getenv('DEBUG') != null
-	}
+    testClassesDirs = sourceSets.test.output.classesDirs  // tells Gradle WHERE test classes are
+    classpath = sourceSets.test.runtimeClasspath          // gives JUnit all dependencies it needs
+    useJUnitPlatform {
+        includeTags 'integration'
+    }
+    testLogging {
+        events 'passed', 'skipped', 'failed'
+        showStandardStreams = System.getenv('DEBUG') != null
+    }
 }
 
 java {

src/main/java/com/meilisearch/sdk/Index.java

@@ -1435,6 +1435,49 @@ public TaskInfo resetEmbeddersSettings() throws MeilisearchException {
         return this.settingsHandler.resetEmbedders(this.uid);
     }
 
+    /**
+     * Gets the foreign keys settings of the index.
+     *
+     * <p>Foreign keys are an experimental feature (Meilisearch v1.39+) that allow cross-index
+     * document hydration. The user must enable this experimental feature on their Meilisearch
+     * instance before using these settings.
+     *
+     * @return an array of ForeignKey that describes cross-index relationships
+     * @throws MeilisearchException if an error occurs
+     * @see <a href="https://www.meilisearch.com/docs/reference/api/settings/get-foreignkeys">API
+     *     specification</a>
+     */
+    public ForeignKey[] getForeignKeysSettings() throws MeilisearchException {
+        // Delegates to SettingsHandler, passing the index uid.
+        return this.settingsHandler.getForeignKeysSettings(this.uid);
+    }
+
+    /**
+     * Updates the foreign keys settings of the index.
+     *
+     * @param foreignKeys an array of ForeignKey objects describing cross-index relationships
+     * @return TaskInfo instance
+     * @throws MeilisearchException if an error occurs
+     * @see <a href="https://www.meilisearch.com/docs/reference/api/settings/update-foreignkeys">API
+     *     specification</a>
+     */
+    public TaskInfo updateForeignKeysSettings(ForeignKey[] foreignKeys)
+            throws MeilisearchException {
+        return this.settingsHandler.updateForeignKeysSettings(this.uid, foreignKeys);
+    }
+
+    /**
+     * Resets the foreign keys settings of the index to the default (empty) value.
+     *
+     * @return TaskInfo instance
+     * @throws MeilisearchException if an error occurs
+     * @see <a href="https://www.meilisearch.com/docs/reference/api/settings/reset-foreignkeys">API
+     *     specification</a>
+     */
+    public TaskInfo resetForeignKeysSettings() throws MeilisearchException {
+        return this.settingsHandler.resetForeignKeysSettings(this.uid);
+    }
+
     /**
      * Compacts the database for this index to reclaim unused space
      *

src/main/java/com/meilisearch/sdk/SettingsHandler.java

@@ -6,6 +6,7 @@
 import com.meilisearch.sdk.model.Faceting;
 import com.meilisearch.sdk.model.FilterableAttributesConfig;
 import com.meilisearch.sdk.model.FilterableAttributesLegacyAdapter;
+import com.meilisearch.sdk.model.ForeignKey;
 import com.meilisearch.sdk.model.LocalizedAttribute;
 import com.meilisearch.sdk.model.Pagination;
 import com.meilisearch.sdk.model.Settings;
@@ -853,4 +854,61 @@ TaskInfo resetEmbedders(String uid) throws MeilisearchException {
         return httpClient.delete(
                 settingsPath(uid).addSubroute("embedders").getURL(), TaskInfo.class);
     }
+
+    /**
+     * Gets the foreign keys settings of the index.
+     *
+     * <p>Foreign keys are an experimental feature (Meilisearch v1.39+) that allow cross-index
+     * document hydration. The user must enable this experimental feature on their Meilisearch
+     * instance before using these settings.
+     *
+     * @param uid Index identifier
+     * @return an array of ForeignKey that contains the foreign keys settings
+     * @throws MeilisearchException if an error occurs
+     * @see <a href="https://www.meilisearch.com/docs/reference/api/settings/get-foreignkeys">API
+     *     specification</a>
+     */
+    ForeignKey[] getForeignKeysSettings(String uid) throws MeilisearchException {
+        // GET /indexes/{uid}/settings/foreign-keys
+        // Returns an array of ForeignKey objects, each with a foreignIndexUid and fieldName.
+        return httpClient.get(
+                settingsPath(uid).addSubroute("foreign-keys").getURL(), ForeignKey[].class);
+    }
+
+    /**
+     * Updates the foreign keys settings of the index.
+     *
+     * @param uid Index identifier
+     * @param foreignKeys an array of ForeignKey objects describing cross-index relationships
+     * @return TaskInfo instance
+     * @throws MeilisearchException if an error occurs
+     * @see <a href="https://www.meilisearch.com/docs/reference/api/settings/update-foreignkeys">API
+     *     specification</a>
+     */
+    TaskInfo updateForeignKeysSettings(String uid, ForeignKey[] foreignKeys)
+            throws MeilisearchException {
+        // PUT /indexes/{uid}/settings/foreign-keys
+        // If foreignKeys is null, we encode it as a JSON null to reset the setting.
+        // Otherwise we send the array directly and let the HTTP client serialize it to JSON.
+        return httpClient.put(
+                settingsPath(uid).addSubroute("foreign-keys").getURL(),
+                foreignKeys == null ? httpClient.jsonHandler.encode(foreignKeys) : foreignKeys,
+                TaskInfo.class);
+    }
+
+    /**
+     * Resets the foreign keys settings of the index to the default (empty) value.
+     *
+     * @param uid Index identifier
+     * @return TaskInfo instance
+     * @throws MeilisearchException if an error occurs
+     * @see <a href="https://www.meilisearch.com/docs/reference/api/settings/reset-foreignkeys">API
+     *     specification</a>
+     */
+    TaskInfo resetForeignKeysSettings(String uid) throws MeilisearchException {
+        // DELETE /indexes/{uid}/settings/foreign-keys resets the setting to its default empty
+        // value.
+        return httpClient.delete(
+                settingsPath(uid).addSubroute("foreign-keys").getURL(), TaskInfo.class);
+    }
 }

src/main/java/com/meilisearch/sdk/model/ForeignKey.java

@@ -0,0 +1,28 @@
+package com.meilisearch.sdk.model;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+/**
+ * ForeignKey setting data structure for cross-index document hydration.
+ *
+ * <p>Each ForeignKey entry links a field in the current index to a field in another index, allowing
+ * search results to be automatically enriched with related data.
+ *
+ * @see <a href="https://www.meilisearch.com/docs/reference/api/settings/get-foreignkeys">API
+ *     specification</a>
+ */
+@Getter
+@Setter
+@AllArgsConstructor
+@NoArgsConstructor
+public class ForeignKey {
+
+    // The uid of the foreign (related) index this entry points to.
+    protected String foreignIndexUid;
+
+    // The name of the field in the current index that holds the foreign key value.
+    protected String fieldName;
+}

src/main/java/com/meilisearch/sdk/model/Settings.java

@@ -39,6 +39,10 @@ public class Settings {
     protected HashMap<String, Embedder> embedders;
     protected LocalizedAttribute[] localizedAttributes;
 
+    // Holds the list of foreign key relationships for cross-index document hydration.
+    // This is an experimental Meilisearch feature (v1.39+).
+    protected ForeignKey[] foreignKeys;
+
     public Settings() {}
 
     /** Granular filterable attributes accessor. */