Implemented GitHub feedback

Author: Robbie-Microsoft

src/client/Microsoft.Identity.Client/Http/Retry/CsrMetadataProbeRetryPolicy.cs renamed to src/client/Microsoft.Identity.Client/Http/Retry/ImdsProbeRetryPolicy.cs

@@ -276,6 +276,7 @@ public static async Task<bool> ProbeImdsEndpointAsync(
 
             var queryParams = ImdsQueryParamsHelper(requestContext, apiVersionQueryParam, imdsApiVersion);
 
+            // probe omits the "Metadata: true" header and then treats 400 Bad Request as success
             var headers = new Dictionary<string, string>
             {
                 { OAuth2Header.XMsCorrelationId, requestContext.CorrelationId.ToString() }
@@ -310,6 +311,7 @@ public static async Task<bool> ProbeImdsEndpointAsync(
                 return false;
             }
 
+            // probe omits the "Metadata: true" header and then treats 400 Bad Request as success
             if (response.StatusCode == HttpStatusCode.BadRequest)
             {
                 requestContext.Logger.Info(() => $"[Managed Identity] {imdsStringHelper} managed identity is available.");

src/client/Microsoft.Identity.Client/ManagedIdentity/ImdsManagedIdentitySource.cs

@@ -93,7 +93,7 @@ private async Task<AbstractManagedIdentity> GetOrSelectManagedIdentitySourceAsyn
                     ManagedIdentitySource.AzureArc => AzureArcManagedIdentitySource.Create(requestContext),
                     ManagedIdentitySource.ImdsV2 => ImdsV2ManagedIdentitySource.Create(requestContext),
                     ManagedIdentitySource.Imds => ImdsManagedIdentitySource.Create(requestContext),
-                    _ => throw new MsalServiceException(MsalError.ManagedIdentityAllSourcesUnavailable, MsalErrorMessage.ManagedIdentityAllSourcesUnavailable)
+                    _ => throw new MsalClientException(MsalError.ManagedIdentityAllSourcesUnavailable, MsalErrorMessage.ManagedIdentityAllSourcesUnavailable)
                 };
             }
         }
@@ -102,8 +102,7 @@ private async Task<AbstractManagedIdentity> GetOrSelectManagedIdentitySourceAsyn
         // This method is perf sensitive any changes should be benchmarked.
         internal async Task<ManagedIdentitySource> GetManagedIdentitySourceAsync(
             RequestContext requestContext,
-            bool isMtlsPopRequested,
-            bool noImdsV2 = false)
+            bool isMtlsPopRequested)
         {
             // First check env vars to avoid the probe if possible
             ManagedIdentitySource source = GetManagedIdentitySourceNoImds(requestContext.Logger);

src/client/Microsoft.Identity.Client/ManagedIdentity/ManagedIdentityClient.cs

@@ -63,11 +63,11 @@ public async Task<ManagedIdentitySource> GetManagedIdentitySourceAsync()
                 return ManagedIdentityClient.s_sourceName;
             }
 
-            // Create a temporary RequestContext for the CSR metadata probe request.
-            var csrMetadataProbeRequestContext = new RequestContext(this.ServiceBundle, Guid.NewGuid(), null, CancellationToken.None);
+            // Create a temporary RequestContext for the logger and the IMDS probe request.
+            var requestContext = new RequestContext(this.ServiceBundle, Guid.NewGuid(), null, CancellationToken.None);
 
             // GetManagedIdentitySourceAsync might return ImdsV2 = true, but it still requires .WithMtlsProofOfPossesion on the Managed Identity Application object to hit the ImdsV2 flow
-            return await ManagedIdentityClient.GetManagedIdentitySourceAsync(csrMetadataProbeRequestContext, isMtlsPopRequested: true).ConfigureAwait(false);
+            return await ManagedIdentityClient.GetManagedIdentitySourceAsync(requestContext, isMtlsPopRequested: true).ConfigureAwait(false);
         }
 
         /// <summary>

src/client/Microsoft.Identity.Client/ManagedIdentityApplication.cs

@@ -464,7 +464,7 @@ public async Task ProbeImdsEndpointAsync_TimesOutAfterOneSecond()
                 var miSource = await (managedIdentityApp as ManagedIdentityApplication).GetManagedIdentitySourceAsync().ConfigureAwait(false);
                 Assert.AreEqual(ManagedIdentitySource.None, miSource); // Probe timed out, no source available
 
-                var ex = await Assert.ThrowsExceptionAsync<MsalServiceException>(async () =>
+                var ex = await Assert.ThrowsExceptionAsync<MsalClientException>(async () =>
                     await managedIdentityApp.AcquireTokenForManagedIdentity(ManagedIdentityTests.Resource)
                     .ExecuteAsync().ConfigureAwait(false)
                 ).ConfigureAwait(false);

tests/Microsoft.Identity.Test.Unit/ManagedIdentityTests/ImdsTests.cs

@@ -1162,7 +1162,7 @@ public async Task UnavailableManagedIdentitySource_ThrowsExceptionDuringTokenAcq
 
                 httpManager.AddMockHandler(MockHelpers.MockImdsProbeFailure(ImdsVersion.V1));
 
-                MsalServiceException ex = await Assert.ThrowsExceptionAsync<MsalServiceException>(async () =>
+                var ex = await Assert.ThrowsExceptionAsync<MsalClientException>(async () =>
                     await mi.AcquireTokenForManagedIdentity("https://management.azure.com")
                         .ExecuteAsync()
                         .ConfigureAwait(false)).ConfigureAwait(false);