fix(scheduler): default Configuration.participants to empty list (#316)

Signed-off-by: SAY-5 <say.apm35@gmail.com>
Co-authored-by: Gordan Ovcaric <gordan.ovcaric@hotmail.com>

Author: SAY-5

.claude/settings.local.json

@@ -12,7 +12,9 @@
       "Bash(/usr/libexec/java_home:*)",
       "Bash(./gradlew clean test:*)",
       "Bash(./gradlew:*)",
-      "Bash(./gradlew build:*)"
+      "Bash(./gradlew build:*)",
+      "Bash(gh pr *)",
+      "Bash(gh issue *)"
     ]
   }
 }

CHANGELOG.md

@@ -7,6 +7,9 @@
   Valid values are strings `"1"` through `"11"`.
   See [Google Calendar Colors](https://developers.google.com/calendar/api/v3/reference/colors).
 
+### Fixed
+* `Configuration.participants` now defaults to an empty list when the field is absent from the API response (e.g. group-event configurations), preventing a `JsonDataException` from being thrown during deserialization.
+
 ## [v2.15.1] - Release 2026-03-30
 
 ### Changed

src/main/kotlin/com/nylas/models/Scheduler.kt

@@ -12,10 +12,13 @@ data class Configuration(
   @Json(name = "id")
   val id: String,
   /**
-   * List of participants included in the scheduled event.
+   * List of participants included in the scheduled event. The Nylas API
+   * omits this field for group-event configurations, so default to an
+   * empty list to avoid a JsonDataException on deserialization while
+   * keeping the property's runtime type unchanged for existing callers.
    */
   @Json(name = "participants")
-  val participants: List<ConfigurationParticipant>,
+  val participants: List<ConfigurationParticipant> = emptyList(),
   /**
    * Rules that determine available time slots for the event.
    */

src/test/kotlin/com/nylas/resources/ConfigurationsTest.kt

@@ -231,6 +231,28 @@ class ConfigurationsTest {
       assertEquals("Custom Body", emailTemplate.bookingConfirmed?.body)
     }
 
+    @Test
+    fun `Configuration without participants field deserializes to empty list`() {
+      val adapter = JsonHelper.moshi().adapter(Configuration::class.java)
+      val jsonBuffer = Buffer().writeUtf8(
+        """
+        {
+          "id": "group-config-id",
+          "availability": {
+              "duration_minutes": 30
+          },
+          "event_booking": {
+              "title": "Group Event"
+          }
+        }
+        """.trimIndent(),
+      )
+      val config = adapter.fromJson(jsonBuffer)!!
+      assertIs<Configuration>(config)
+      assertEquals("group-config-id", config.id)
+      assertEquals(emptyList(), config.participants)
+    }
+
     @Test
     fun `AdditionalFieldType METADATA serializes correctly`() {
       val adapter = JsonHelper.moshi().adapter(AdditionalField::class.java)