From 28cd2f8782029e6cf4cc569ecd357c8c9f0b1a64 Mon Sep 17 00:00:00 2001
From: Jocelyn <41338290+jaschrep-msft@users.noreply.github.com>
Date: Thu, 9 May 2024 13:36:52 -0400
Subject: [PATCH] expect-continue header compat switch (#43888)

---
 .../Azure.Storage.Common/src/Shared/CompatSwitches.cs        | 5 +++++
 sdk/storage/Azure.Storage.Common/src/Shared/Constants.cs     | 3 +++
 .../src/Shared/ExpectContinueOnThrottlePolicy.cs             | 3 ++-
 .../Azure.Storage.Common/src/Shared/ExpectContinuePolicy.cs  | 2 +-
 .../tests/Azure.Storage.Common.Tests.csproj                  | 1 +
 5 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/sdk/storage/Azure.Storage.Common/src/Shared/CompatSwitches.cs b/sdk/storage/Azure.Storage.Common/src/Shared/CompatSwitches.cs
index 05a3d8567f78..04e4f7cd4cf9 100644
--- a/sdk/storage/Azure.Storage.Common/src/Shared/CompatSwitches.cs
+++ b/sdk/storage/Azure.Storage.Common/src/Shared/CompatSwitches.cs
@@ -11,5 +11,10 @@ internal static class CompatSwitches
 
         public static bool DisableRequestConditionsValidation => _disableRequestConditionsValidation
             ??= AppContextSwitchHelper.GetConfigValue(Constants.DisableRequestConditionsValidationSwitchName, Constants.DisableRequestConditionsValidationEnvVar);
+
+        private static bool? _disableExpectContinueHeader;
+
+        public static bool DisableExpectContinueHeader => _disableExpectContinueHeader
+            ??= AppContextSwitchHelper.GetConfigValue(Constants.DisableExpectContinueHeaderSwitchName, Constants.DisableExpectContinueHeaderEnvVar);
     }
 }
diff --git a/sdk/storage/Azure.Storage.Common/src/Shared/Constants.cs b/sdk/storage/Azure.Storage.Common/src/Shared/Constants.cs
index e0c721ed2466..c8ce04f6f4e4 100644
--- a/sdk/storage/Azure.Storage.Common/src/Shared/Constants.cs
+++ b/sdk/storage/Azure.Storage.Common/src/Shared/Constants.cs
@@ -123,6 +123,9 @@ internal static class Constants
         public const string DisableRequestConditionsValidationSwitchName = "Azure.Storage.DisableRequestConditionsValidation";
         public const string DisableRequestConditionsValidationEnvVar = "AZURE_STORAGE_DISABLE_REQUEST_CONDITIONS_VALIDATION";
 
+        public const string DisableExpectContinueHeaderSwitchName = "Azure.Storage.DisableExpectContinueHeader";
+        public const string DisableExpectContinueHeaderEnvVar = "AZURE_STORAGE_DISABLE_EXPECT_CONTINUE_HEADER";
+
         public const string DefaultScope = "/.default";
 
         /// <summary>
diff --git a/sdk/storage/Azure.Storage.Common/src/Shared/ExpectContinueOnThrottlePolicy.cs b/sdk/storage/Azure.Storage.Common/src/Shared/ExpectContinueOnThrottlePolicy.cs
index 57bcb6abb62d..5d3c60d61aec 100644
--- a/sdk/storage/Azure.Storage.Common/src/Shared/ExpectContinueOnThrottlePolicy.cs
+++ b/sdk/storage/Azure.Storage.Common/src/Shared/ExpectContinueOnThrottlePolicy.cs
@@ -24,7 +24,8 @@ public TimeSpan ThrottleInterval
     public override void OnSendingRequest(HttpMessage message)
     {
         if (message.Request.Content == null ||
-            (message.Request.Content.TryComputeLength(out long contentLength) && contentLength < ContentLengthThreshold))
+            (message.Request.Content.TryComputeLength(out long contentLength) && contentLength < ContentLengthThreshold) ||
+            CompatSwitches.DisableExpectContinueHeader)
         {
             return;
         }
diff --git a/sdk/storage/Azure.Storage.Common/src/Shared/ExpectContinuePolicy.cs b/sdk/storage/Azure.Storage.Common/src/Shared/ExpectContinuePolicy.cs
index dfe8afd71fd7..fdd2dcfb143a 100644
--- a/sdk/storage/Azure.Storage.Common/src/Shared/ExpectContinuePolicy.cs
+++ b/sdk/storage/Azure.Storage.Common/src/Shared/ExpectContinuePolicy.cs
@@ -12,7 +12,7 @@ internal class ExpectContinuePolicy : HttpPipelineSynchronousPolicy
 
     public override void OnSendingRequest(HttpMessage message)
     {
-        if (message.Request.Content == null)
+        if (message.Request.Content == null || CompatSwitches.DisableExpectContinueHeader)
         {
             return;
         }
diff --git a/sdk/storage/Azure.Storage.Common/tests/Azure.Storage.Common.Tests.csproj b/sdk/storage/Azure.Storage.Common/tests/Azure.Storage.Common.Tests.csproj
index 3d9f099791c8..5db86ebee984 100644
--- a/sdk/storage/Azure.Storage.Common/tests/Azure.Storage.Common.Tests.csproj
+++ b/sdk/storage/Azure.Storage.Common/tests/Azure.Storage.Common.Tests.csproj
@@ -29,6 +29,7 @@
     <Compile Include="$(AzureStorageSharedSources)BufferExtensions.cs" LinkBase="Shared" />
     <Compile Include="$(AzureStorageSharedSources)ChecksumCalculatingStream.cs" LinkBase="Shared" />
     <Compile Include="$(AzureStorageSharedSources)ContentHasher.cs" LinkBase="Shared" />
+    <Compile Include="$(AzureStorageSharedSources)CompatSwitches.cs" LinkBase="Shared" />
     <Compile Include="$(AzureStorageSharedSources)DisposableBucket.cs" LinkBase="Shared" />
     <Compile Include="$(AzureStorageSharedSources)ExpectContinuePolicy.cs" LinkBase="Shared" />
     <Compile Include="$(AzureStorageSharedSources)ExpectContinueOnThrottlePolicy.cs" LinkBase="Shared" />