Fix ArgumentOutOfRangeException when token has default ExpiresOn value (#47040)

Author: christothes

sdk/core/Azure.Core/CHANGELOG.md

@@ -8,6 +8,8 @@
 
 ### Bugs Fixed
 
+- Fixed an issue where `BearerTokenAuthenticationPolicy` throws `ArgumentOutOfRangeException` if the `ExpiresOn` property of the token is the default value. ([#47040](https://github.com/Azure/azure-sdk-for-net/pull/47040))
+
 ### Other Changes
 
 - Use `BinaryData.Empty` for `PipelineResponse.Content` when HTTP message has no content.

sdk/core/Azure.Core/src/Pipeline/BearerTokenAuthenticationPolicy.cs

@@ -395,7 +395,14 @@ private async ValueTask SetResultOnTcsFromCredentialAsync(TokenRequestContext co
                     ? await _credential.GetTokenAsync(context, cancellationToken).ConfigureAwait(false)
                     : _credential.GetToken(context, cancellationToken);
 
-                targetTcs.SetResult(new AuthHeaderValueInfo("Bearer " + token.Token, token.ExpiresOn, token.RefreshOn.HasValue ? token.RefreshOn.Value : token.ExpiresOn - _tokenRefreshOffset));
+                DateTimeOffset refreshOn = token.RefreshOn.HasValue switch
+                {
+                    true => token.RefreshOn.Value,
+                    false when _tokenRefreshOffset.Ticks > token.ExpiresOn.Ticks => token.ExpiresOn,
+                    _ => token.ExpiresOn - _tokenRefreshOffset
+                };
+
+                targetTcs.SetResult(new AuthHeaderValueInfo("Bearer " + token.Token, token.ExpiresOn, refreshOn));
             }
 
             internal readonly struct AuthHeaderValueInfo

sdk/core/Azure.Core/tests/BearerTokenAuthenticationPolicyTests.cs

@@ -57,6 +57,30 @@ public async Task BearerTokenAuthenticationPolicy_RequestsTokenEveryRequest()
             Assert.AreEqual("Bearer token2", auth2Value);
         }
 
+        [Test]
+        public async Task BearerTokenAuthenticationPolicy_RequestsTokenEveryRequest_InvalidExpiresOn()
+        {
+            var accessTokens = new Queue<AccessToken>();
+            accessTokens.Enqueue(new AccessToken("token1", default));
+            accessTokens.Enqueue(new AccessToken("token2", default));
+
+            var credential = new TokenCredentialStub(
+                (r, c) => r.Scopes.SequenceEqual(new[] { "scope1", "scope2" }) ? accessTokens.Dequeue() : default,
+                IsAsync);
+
+            var policy = new BearerTokenAuthenticationPolicy(credential, new[] { "scope1", "scope2" });
+            MockTransport transport = CreateMockTransport(new MockResponse(200), new MockResponse(200));
+
+            await SendGetRequest(transport, policy, uri: new Uri("https://example.com"));
+            await SendGetRequest(transport, policy, uri: new Uri("https://example.com"));
+
+            Assert.True(transport.Requests[0].Headers.TryGetValue("Authorization", out string auth1Value));
+            Assert.True(transport.Requests[1].Headers.TryGetValue("Authorization", out string auth2Value));
+
+            Assert.AreEqual("Bearer token1", auth1Value);
+            Assert.AreEqual("Bearer token2", auth2Value);
+        }
+
         [Test]
         public async Task BearerTokenAuthenticationPolicy_CachesHeaderValue()
         {