From 238e23a1761831d279fdea748877b9e0f5ce56e7 Mon Sep 17 00:00:00 2001
From: Sourabh Jain <sourabh.jain.107@gmail.com>
Date: Thu, 1 Jul 2021 02:56:21 +0530
Subject: [PATCH] LINQ : Fixes ArgumentNullException while calling
 ToQueryDefinition() (#2580)

This fixes ArguementNullException in ToQueryDefinition for read feed scenarios where there has been no filters applied to the linq query.
---
 .../src/Query/v3Query/QueryDefinition.cs             |  3 ++-
 .../CosmosItemLinqTests.cs                           | 12 ++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/Microsoft.Azure.Cosmos/src/Query/v3Query/QueryDefinition.cs b/Microsoft.Azure.Cosmos/src/Query/v3Query/QueryDefinition.cs
index d68a4fcea5..c1eed49cb3 100644
--- a/Microsoft.Azure.Cosmos/src/Query/v3Query/QueryDefinition.cs
+++ b/Microsoft.Azure.Cosmos/src/Query/v3Query/QueryDefinition.cs
@@ -55,7 +55,8 @@ internal static QueryDefinition CreateFromQuerySpec(SqlQuerySpec sqlQuery)
         {
             if (sqlQuery == null)
             {
-                throw new ArgumentNullException(nameof(sqlQuery));
+                // It is to support scenarios where all the data needs to be read 
+                return null;
             }
 
             QueryDefinition queryDefinition = new QueryDefinition(sqlQuery.QueryText);
diff --git a/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.EmulatorTests/CosmosItemLinqTests.cs b/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.EmulatorTests/CosmosItemLinqTests.cs
index 5d72595e39..849b2afd0a 100644
--- a/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.EmulatorTests/CosmosItemLinqTests.cs
+++ b/Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.EmulatorTests/CosmosItemLinqTests.cs
@@ -797,6 +797,18 @@ async Task TestSearch(Expression<Func<ToDoActivity, bool>> expression, string ex
 
         }
 
+        [TestMethod]
+        public async Task LinqSelectEverythingWithoutQueryableTest()
+        {
+            await ToDoActivity.CreateRandomItems(this.Container, pkCount: 2, perPKItemCount: 1, randomPartitionKey: true);
+
+            QueryDefinition queryDefinition = this.Container
+                 .GetItemLinqQueryable<ToDoActivity>()
+                 .ToQueryDefinition();
+
+            Assert.AreEqual(2, (await this.FetchResults<ToDoActivity>(queryDefinition)).Count);
+        }
+
         private class NumberLinqItem
         {
             public string id;