From 86535e24aa8aa1523480336ae57e7fdf885f0bb2 Mon Sep 17 00:00:00 2001
From: Kishore Nallan <kishorenc@gmail.com>
Date: Sun, 5 Feb 2023 13:20:02 +0530
Subject: [PATCH] Improve error message for nested array object string field.

---
 src/index.cpp                          |  8 ++++++++
 test/collection_nested_fields_test.cpp | 25 +++++++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/src/index.cpp b/src/index.cpp
index f599eab6..c3db97b7 100644
--- a/src/index.cpp
+++ b/src/index.cpp
@@ -5557,6 +5557,10 @@ Option<uint32_t> Index::coerce_string(const DIRTY_VALUES& dirty_values, const st
     else {
         if(dirty_values == DIRTY_VALUES::COERCE_OR_DROP) {
             if(!a_field.optional) {
+                if(a_field.nested && item.is_array()) {
+                    return Option<>(400, "Field `" + field_name + "` has an incorrect type. "
+                                      "Hint: field inside an array of objects must be an array type as well.");
+                }
                 return Option<>(400, "Field `" + field_name  + "` must be " + suffix + " string.");
             }
 
@@ -5568,6 +5572,10 @@ Option<uint32_t> Index::coerce_string(const DIRTY_VALUES& dirty_values, const st
             }
         } else {
             // COERCE_OR_REJECT / non-optional + DROP
+            if(a_field.nested && item.is_array()) {
+                return Option<>(400, "Field `" + field_name + "` has an incorrect type. "
+                                      "Hint: field inside an array of objects must be an array type as well.");
+            }
             return Option<>(400, "Field `" + field_name  + "` must be " + suffix + " string.");
         }
     }
diff --git a/test/collection_nested_fields_test.cpp b/test/collection_nested_fields_test.cpp
index 997026a7..87a58145 100644
--- a/test/collection_nested_fields_test.cpp
+++ b/test/collection_nested_fields_test.cpp
@@ -1445,6 +1445,31 @@ TEST_F(CollectionNestedFieldsTest, ExplicitSchemaOptionalFieldValidation) {
     }
 }
 
+TEST_F(CollectionNestedFieldsTest, ExplicitSchemaForNestedArrayTypeValidation) {
+    nlohmann::json schema = R"({
+        "name": "coll1",
+        "enable_nested_fields": true,
+        "fields": [
+            {"name": "blocks.text", "type": "object[]"},
+            {"name": "blocks.text.description", "type": "string"}
+        ]
+    })"_json;
+
+    auto op = collectionManager.create_collection(schema);
+    ASSERT_TRUE(op.ok());
+    Collection* coll1 = op.get();
+
+    auto doc1 = R"({
+        "blocks": {"text": [{"description": "Hello world."}]}
+    })"_json;
+
+    auto add_op = coll1->add(doc1.dump(), CREATE);
+
+    ASSERT_FALSE(add_op.ok());
+    ASSERT_EQ("Field `blocks.text.description` has an incorrect type. "
+              "Hint: field inside an array of objects must be an array type as well.", add_op.error());
+}
+
 TEST_F(CollectionNestedFieldsTest, SortByNestedField) {
     nlohmann::json schema = R"({
         "name": "coll1",