[wasm] System.Net.Http.BrowserHttpHandler.SendAsync() throws NRE

[pavelsavara]

In unit test System.Net.Http.Functional.Tests.HttpClientHandler_RemoteServerTest.GetAsync_RequestHeadersAddCustomHeaders_HeaderAndEmptyValueSent(remoteServer: (BaseUri: https://127.0.0.1:61813/, HttpVersion: 1.1) on WASM and browser.

System.NullReferenceException : Object reference not set to an instance of an object.
   at System.Net.Http.BrowserHttpHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.<SendAsync>g__Core|83_0(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationTokenSource cts, Boolean disposeCts, CancellationTokenSource pendingRequestsCts, CancellationToken originalCancellationToken)
   at System.Net.Http.Functional.Tests.HttpClientHandler_RemoteServerTest.GetAsync_RequestHeadersAddCustomHeaders_HeaderAndEmptyValueSent(RemoteServer remoteServer, Uri uri)

This is not network related issue, it could be reproduced without BrowserHttpHandler see https://github.com/dotnet/runtime/pull/54453/files

[ghost]

Tagging subscribers to this area: @dotnet/ncl
See info in area-owners.md if you want to be subscribed.

Issue Details

---

In unit test System.Net.Http.Functional.Tests.HttpClientHandler_RemoteServerTest.GetAsync_RequestHeadersAddCustomHeaders_HeaderAndEmptyValueSent(remoteServer: (BaseUri: https://127.0.0.1:61813/, HttpVersion: 1.1) on WASM and browser.

System.NullReferenceException : Object reference not set to an instance of an object.
   at System.Net.Http.BrowserHttpHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.<SendAsync>g__Core|83_0(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationTokenSource cts, Boolean disposeCts, CancellationTokenSource pendingRequestsCts, CancellationToken originalCancellationToken)
   at System.Net.Http.Functional.Tests.HttpClientHandler_RemoteServerTest.GetAsync_RequestHeadersAddCustomHeaders_HeaderAndEmptyValueSent(RemoteServer remoteServer, Uri uri)

Author:	pavelsavara
Assignees:	-
Labels:	arch-wasm, area-System.Net.Http
Milestone:	-

[lewing]

Looking at the test I don't see an obvious reason it should fail like this. Is this failing on all browser lanes? There was some work done allow trimming more of the header logic out and if these tests weren't running they may have regressed.

[pavelsavara]

Here is example of the failure on CI
https://helixre8s23ayyeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-pull-53925-merge-160a064b73f24741b2/System.Net.Http.Functional.Tests/console.3a6c0e9f.log?sv=2019-07-07&se=2021-06-30T09%3A14%3A59Z&sr=c&sp=rl&sig=qBO1wWtqkq9AGYRX0b82P6An%2BBE0LKFnuckJY0ed6BU%3D

This time different test and on ubuntu, not windows.
System.Net.Http.Functional.Tests.HttpClientHandler_RemoteServerTest.GetAsync_ServerNeedsAuthAndNoCredential_StatusCodeUnauthorized

Maybe race condition ?

[pavelsavara]

Yes second CI run on the same code as above is green.

[pavelsavara]

Another locally

System.Net.Http.Functional.Tests.HttpClientHandler_RemoteServerTest.GetAsync_RequestHeadersAddCustomHeaders_HeaderAndValueSent(remoteServer: (BaseUri: https://127.0.0.1:57664/, HttpVersion: 1.1), name: "X-CustomHeader", value: "x-value", uri: https://127.0.0.1:57664/Echo.ashx)
  info: System.NullReferenceException : Object reference not set to an instance of an object.
  info:    at System.Net.Http.BrowserHttpHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
  info:    at System.Net.Http.HttpClient.<SendAsync>g__Core|83_0(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationTokenSource cts, Boolean disposeCts, CancellationTokenSource pendingRequestsCts, CancellationToken originalCancellationToken)
  info:    at System.Net.Http.Functional.Tests.HttpClientHandler_RemoteServerTest.GetAsync_RequestHeadersAddCustomHeaders_HeaderAndValueSent(RemoteServer remoteServer, String name, String value, Uri uri)

[pavelsavara]

System.ArgumentNullException : Value cannot be null. (Parameter 'fetchResponse')
  info:    at System.Net.Http.BrowserHttpHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)

[pavelsavara]

Repro at pavelsavara@a2b0a7b#diff-66ce677ded58c3a6a0639d321f4460bb0b2c4bcaeb3216ff3db4381937365bd8

It fails randomly with s, q, x3 and x10 as last state

I think JSObject is returned as null from some of the marshaling calls.

@lewing @kg thoughts ?

[kg]

Most likely explanation is a GC issue. I think if it were memory corruption in the runtime (which has been known to happen, but hasn't - afaik - been seen recently) it wouldn't just be consistently producing NREs, other bad stuff would be happening.

[pavelsavara]

Very simple steps to reproduce here https://github.com/dotnet/runtime/pull/54453/files

dotnet build /p:TargetOS=Browser /p:TargetArchitecture=wasm /p:Configuration=Release /t:Test src\libraries\System.Private.Runtime.InteropServices.JavaScript\tests /p:WithCategories="Pavel"

[lewing]

looks similar to

[20:02:53] info: Initializing.....
[20:02:55] info: {"method":"console.error","payload":{},"arguments":[{}]}
[20:02:55] fail: Error: System.NullReferenceException: Object reference not set to an instance of an object.
                    at System.Runtime.InteropServices.JavaScript.Runtime.<>c__DisplayClass27_0.<SetupJSContinuation>g__Complete|0()
                    at System.Runtime.InteropServices.JavaScript.Runtime.SetupJSContinuation(Task task, JSObject continuationObj)
                     at Object._convert_exception_for_method_call (http://127.0.0.1:35977/dotnet.js:1:171696)
                     at Object._handle_exception_for_call (http://127.0.0.1:35977/dotnet.js:1:173665)
                     at Object._handle_exception_and_produce_result_for_call (http://127.0.0.1:35977/dotnet.js:1:173986)
                     at Object._call_method_with_converted_args (http://127.0.0.1:35977/dotnet.js:1:175060)
                     at Object.call_method (http://127.0.0.1:35977/dotnet.js:1:173455)
                     at Object._unbox_task_rooted (http://127.0.0.1:35977/dotnet.js:1:152563)
                     at Object._unbox_mono_obj_rooted_with_known_nonprimitive_type (http://127.0.0.1:35977/dotnet.js:1:153449)
                     at Object._unbox_mono_obj_root (http://127.0.0.1:35977/dotnet.js:1:154685)
                     at Object._handle_exception_and_produce_result_for_call (http://127.0.0.1:35977/dotnet.js:1:174106)
                     at Object._call_method_with_converted_args (http://127.0.0.1:35977/dotnet.js:1:175060)
[20:02:55] info: Discovering: System.Xml.Linq.xNodeBuilder.Tests.dll (method display = ClassAndMethod, method display options = None)
[20:02:55] info: Discovered:  System.Xml.Linq.xNodeBuilder.Tests.dll (found 7 of 8 test cases)
[20:02:55] info: Starting:    System.Xml.Linq.xNodeBuilder.Tests.dll
[20:02:55] info: Finished:    System.Xml.Linq.xNodeBuilder.Tests.dll
[20:02:55] info: 
[20:02:55] info: === TEST EXECUTION SUMMARY ===

from https://dev.azure.com/dnceng/public/_build/results?buildId=1206770&view=logs&j=108d2c4a-8a62-5a58-8dad-8e1042acc93c&t=568f884b-cc12-5fd3-e7fe-790b5ac403f4&l=125