[CHA-1284] feat: add additional fields to channel member request

src/main/java/io/getstream/chat/java/models/Channel.java

@@ -380,6 +380,18 @@ public static class ChannelMemberRequestObject {
     @JsonProperty("shadow_banned")
     private Boolean shadowBanned;
 
+    @Singular @Nullable @JsonIgnore private Map<String, Object> additionalFields;
+
+    @JsonAnyGetter
+    public Map<String, Object> getAdditionalFields() {
+      return this.additionalFields;
+    }
+
+    @JsonAnySetter
+    public void setAdditionalField(String name, Object value) {
+      this.additionalFields.put(name, value);
+    }
+
     @Nullable
     public static ChannelMemberRequestObject buildFrom(@Nullable ChannelMember channelMember) {
       return RequestObjectBuilder.build(ChannelMemberRequestObject.class, channelMember);

src/test/java/io/getstream/chat/java/ChannelTest.java

@@ -555,4 +555,73 @@ void whenArchivingChannelUsingUnset_thenIsArchived() {
                     .request());
     Assertions.assertNull(channelMemberResponse.getMember().getArchivedAt());
   }
+
+  @DisplayName("Can set custom field on channel member")
+  @Test
+  void whenSettingCustomFieldOnMember_thenNoException() {
+    final var customField = "custom_field_on_member";
+    final var customValue = "custom_value";
+
+    var channelMemberReq =
+        ChannelMemberRequestObject.builder()
+            .user(testUserRequestObject)
+            .additionalField(customField, customValue)
+            .build();
+    var channelReq =
+        ChannelRequestObject.builder()
+            .createdBy(testUserRequestObject)
+            .members(List.of(channelMemberReq))
+            .build();
+    var channel =
+        Assertions.assertDoesNotThrow(
+            () ->
+                Channel.getOrCreate(testChannel.getType(), RandomStringUtils.randomAlphabetic(12))
+                    .data(channelReq)
+                    .request());
+
+    Assertions.assertNotNull(channel.getMembers());
+    var members = channel.getMembers();
+    Assertions.assertEquals(1, members.size());
+    var member = members.get(0);
+    Assertions.assertEquals(customValue, member.getAdditionalFields().get(customField));
+  }
+
+  @DisplayName("Can set custom field on channel member")
+  @Test
+  void whenPartialUpdateMember_thenNoException() {
+    var channelType = "messaging";
+    var channelId = RandomStringUtils.randomAlphabetic(12);
+    var channelMemberReq =
+        ChannelMemberRequestObject.builder()
+            .user(testUserRequestObject)
+            .additionalField("field1", "value1")
+            .build();
+    var channelReq =
+        ChannelRequestObject.builder()
+            .createdBy(testUserRequestObject)
+            .members(List.of(channelMemberReq))
+            .build();
+    var channel =
+        Assertions.assertDoesNotThrow(
+            () -> Channel.getOrCreate(channelType, channelId).data(channelReq).request());
+
+    Assertions.assertNotNull(channel.getMembers());
+    var members = channel.getMembers();
+    Assertions.assertEquals(1, members.size());
+    var member = members.get(0);
+    Assertions.assertEquals("value1", member.getAdditionalFields().get("field1"));
+
+    // update partial
+    var partialUpdateResponse =
+        Assertions.assertDoesNotThrow(
+            () ->
+                Channel.updateMemberPartial(channelType, channelId, testUserRequestObject.getId())
+                    .setValue("field1", "updated_value1")
+                    .setValue("field2", "value2")
+                    .request());
+
+    var updatedMember = partialUpdateResponse.getMember();
+    Assertions.assertEquals("updated_value1", updatedMember.getAdditionalFields().get("field1"));
+    Assertions.assertEquals("value2", updatedMember.getAdditionalFields().get("field2"));
+  }
 }