From 730242a3c76223a74e0e061fb442c45f16cedaa3 Mon Sep 17 00:00:00 2001
From: Anatoli Beliaev <anatolib@microsoft.com>
Date: Mon, 15 Jul 2019 13:32:11 -0700
Subject: [PATCH 1/4] Ignore function load requests with duplicate FunctionId
 values.

---
 src/FunctionLoader.cs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/FunctionLoader.cs b/src/FunctionLoader.cs
index 4c2e1064..134aeeef 100644
--- a/src/FunctionLoader.cs
+++ b/src/FunctionLoader.cs
@@ -42,7 +42,10 @@ internal static AzFunctionInfo GetFunctionInfo(string functionId)
         /// </summary>
         internal static void LoadFunction(FunctionLoadRequest request)
         {
-            LoadedFunctions.Add(request.FunctionId, new AzFunctionInfo(request.Metadata));
+            if (!LoadedFunctions.ContainsKey(request.FunctionId))
+            {
+                LoadedFunctions.Add(request.FunctionId, new AzFunctionInfo(request.Metadata));
+            }
         }
 
         /// <summary>

From c550f23bad3906e68509be61fbc6f2998d174f2a Mon Sep 17 00:00:00 2001
From: Anatoli Beliaev <anatolib@microsoft.com>
Date: Mon, 15 Jul 2019 13:54:50 -0700
Subject: [PATCH 2/4] Revert "Ignore function load requests with duplicate
 FunctionId values."

This reverts commit 730242a3c76223a74e0e061fb442c45f16cedaa3.
---
 src/FunctionLoader.cs | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/FunctionLoader.cs b/src/FunctionLoader.cs
index 134aeeef..4c2e1064 100644
--- a/src/FunctionLoader.cs
+++ b/src/FunctionLoader.cs
@@ -42,10 +42,7 @@ internal static AzFunctionInfo GetFunctionInfo(string functionId)
         /// </summary>
         internal static void LoadFunction(FunctionLoadRequest request)
         {
-            if (!LoadedFunctions.ContainsKey(request.FunctionId))
-            {
-                LoadedFunctions.Add(request.FunctionId, new AzFunctionInfo(request.Metadata));
-            }
+            LoadedFunctions.Add(request.FunctionId, new AzFunctionInfo(request.Metadata));
         }
 
         /// <summary>

From d8c7d186c4590f6da0e98ae4b689b285822235a9 Mon Sep 17 00:00:00 2001
From: Anatoli Beliaev <anatolib@microsoft.com>
Date: Mon, 15 Jul 2019 14:09:32 -0700
Subject: [PATCH 3/4] Add FunctionLoader IsLoaded method

---
 src/FunctionLoader.cs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/FunctionLoader.cs b/src/FunctionLoader.cs
index 4c2e1064..c16faa70 100644
--- a/src/FunctionLoader.cs
+++ b/src/FunctionLoader.cs
@@ -36,6 +36,14 @@ internal static AzFunctionInfo GetFunctionInfo(string functionId)
             throw new InvalidOperationException(string.Format(PowerShellWorkerStrings.FunctionNotLoaded, functionId));
         }
 
+        /// <summary>
+        /// Returns true if the function with the given functionId is already loaded.
+        /// </summary>
+        public static bool IsLoaded(string functionId)
+        {
+            return LoadedFunctions.ContainsKey(functionId);
+        }
+
         /// <summary>
         /// This method runs once per 'FunctionLoadRequest' during the code start of the worker.
         /// It will always run synchronously because we process 'FunctionLoadRequest' synchronously.

From 9c34c2092e89a6ac1ce62744be61566b0917d5b1 Mon Sep 17 00:00:00 2001
From: Anatoli Beliaev <anatolib@microsoft.com>
Date: Mon, 15 Jul 2019 14:10:30 -0700
Subject: [PATCH 4/4] Return from ProcessFunctionLoadRequest early if already
 loaded

---
 src/RequestProcessor.cs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/RequestProcessor.cs b/src/RequestProcessor.cs
index d72815c5..e5ca4e16 100644
--- a/src/RequestProcessor.cs
+++ b/src/RequestProcessor.cs
@@ -145,6 +145,16 @@ internal StreamingMessage ProcessFunctionLoadRequest(StreamingMessage request)
                 out StatusResult status);
             response.FunctionLoadResponse.FunctionId = functionLoadRequest.FunctionId;
 
+            // The worker may occasionally receive multiple function load requests with
+            // the same FunctionId. In order to make function load request idempotent,
+            // the worker should ignore the duplicates.
+            if (FunctionLoader.IsLoaded(functionLoadRequest.FunctionId))
+            {
+                // If FunctionLoader considers this function loaded, this means
+                // the previous request was successful, so respond accordingly.
+                return response;
+            }
+
             // When a functionLoadRequest comes in, we check to see if a dependency download has failed in a previous call
             // or if PowerShell could not be initialized. If this is the case, mark this as a failed request
             // and submit the exception to the Host (runtime).