From 19ac76b681f4bbb200e6df67aa45d3ea00e69c02 Mon Sep 17 00:00:00 2001
From: Kishore Nallan <kishorenc@gmail.com>
Date: Fri, 17 Jun 2022 12:13:38 +0530
Subject: [PATCH] Ensure that `id` field cannot be altered.

---
 src/collection.cpp                     |  4 +++
 test/collection_schema_change_test.cpp | 34 ++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/src/collection.cpp b/src/collection.cpp
index acd4e901..e661cdaa 100644
--- a/src/collection.cpp
+++ b/src/collection.cpp
@@ -2810,6 +2810,10 @@ Option<bool> Collection::validate_alter_payload(nlohmann::json& schema_changes,
 
         const std::string& field_name = kv.value()["name"].get<std::string>();
 
+        if(field_name == "id") {
+            return Option<bool>(400, "Field `" + field_name + "` cannot be altered.");
+        }
+
         if(kv.value().contains("drop")) {
             delete_field_names.insert(field_name);
         }
diff --git a/test/collection_schema_change_test.cpp b/test/collection_schema_change_test.cpp
index 8ffd09cc..7409ca27 100644
--- a/test/collection_schema_change_test.cpp
+++ b/test/collection_schema_change_test.cpp
@@ -219,6 +219,17 @@ TEST_F(CollectionSchemaChangeTest, AddNewFieldsToCollection) {
     alter_op = coll1->alter(schema_changes);
     ASSERT_TRUE(alter_op.ok());
 
+    // try to add `id` field
+    schema_changes = R"({
+        "fields": [
+            {"name": "id", "type": "int32"}
+        ]
+    })"_json;
+
+    alter_op = coll1->alter(schema_changes);
+    ASSERT_FALSE(alter_op.ok());
+    ASSERT_EQ("Field `id` cannot be altered.", alter_op.error());
+
     ASSERT_EQ(9, coll1->get_schema().size());
     ASSERT_EQ(12, coll1->get_fields().size());
     ASSERT_EQ(5, coll1->_get_index()->_get_numerical_index().size());
@@ -310,6 +321,17 @@ TEST_F(CollectionSchemaChangeTest, DropFieldsFromCollection) {
     ASSERT_EQ("", coll1->get_fallback_field_type());
     ASSERT_EQ("", coll1->get_default_sorting_field());
 
+    // try to drop `id` field
+    schema_changes = R"({
+        "fields": [
+            {"name": "id", "drop": true}
+        ]
+    })"_json;
+
+    alter_op = coll1->alter(schema_changes);
+    ASSERT_FALSE(alter_op.ok());
+    ASSERT_EQ("Field `id` cannot be altered.", alter_op.error());
+
     // try restoring collection from disk: all fields should be deleted
     collectionManager.dispose();
     delete store;
@@ -476,6 +498,18 @@ TEST_F(CollectionSchemaChangeTest, AlterValidations) {
     ASSERT_FALSE(alter_op.ok());
     ASSERT_EQ("Field `title` has an invalid data type `foobar`, see docs for supported data types.",alter_op.error());
 
+    // add + drop `id` field
+    schema_changes = R"({
+        "fields": [
+            {"name": "id", "drop": true},
+            {"name": "id", "type": "string"}
+        ]
+    })"_json;
+
+    alter_op = coll1->alter(schema_changes);
+    ASSERT_FALSE(alter_op.ok());
+    ASSERT_EQ("Field `id` cannot be altered.", alter_op.error());
+
     collectionManager.drop_collection("coll1");
 }