Remove early dereference of ASPNETCORE_PORT env var (#1225)

- Addresses #1119
- Includes workaround for #1237

src/AspNetCoreModuleV1/AspNetCore/src/serverprocess.cxx

@@ -132,7 +132,6 @@ SERVER_PROCESS::SetupListenPort(
     pEnvironmentVarTable->FindKey(ASPNETCORE_PORT_ENV_STR, &pEntry);
     if (pEntry != NULL)
     {
-        pEntry->Dereference();
         if (pEntry->QueryValue() != NULL || pEntry->QueryValue()[0] != L'\0')
         {
             m_dwPort = (DWORD)_wtoi(pEntry->QueryValue());

test/Common.FunctionalTests/OutOfProcess/AspNetCorePortTests.cs

@@ -0,0 +1,94 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading.Tasks;
+using Xunit;
+using Microsoft.AspNetCore.Server.IIS.FunctionalTests.Utilities;
+using Microsoft.AspNetCore.Server.IntegrationTesting;
+using Microsoft.AspNetCore.Testing.xunit;
+
+namespace Microsoft.AspNetCore.Server.IISIntegration.FunctionalTests
+{
+    [Collection(PublishedSitesCollection.Name)]
+    public class AspNetCorePortTests : IISFunctionalTestBase
+    {
+        private static readonly Random _random = new Random();
+
+        private readonly PublishedSitesFixture _fixture;
+
+        public AspNetCorePortTests(PublishedSitesFixture fixture)
+        {
+            _fixture = fixture;
+        }
+
+        public static TestMatrix TestVariants
+            => TestMatrix.ForServers(DeployerSelector.ServerType)
+                .WithTfms(Tfm.NetCoreApp22)
+                .WithApplicationTypes(ApplicationType.Portable)
+                .WithAllAncmVersions();
+
+        [ConditionalTheory]
+        [MemberData(nameof(TestVariants))]
+        public async Task EnvVarInWebConfig(TestVariant variant)
+        {
+            // Must publish to set env vars in web.config
+            var deploymentParameters = _fixture.GetBaseDeploymentParameters(variant, publish: true);
+
+            // Workaround "PublishedSitesFixture.GetBaseDeploymentParameters() overrides too many properties of baseParameters"
+            // https://github.com/aspnet/IISIntegration/issues/1237
+            deploymentParameters.AncmVersion = variant.AncmVersion;
+
+            var port = GetUnusedRandomPort();
+            deploymentParameters.WebConfigBasedEnvironmentVariables["ASPNETCORE_PORT"] = port.ToString();
+
+            var deploymentResult = await DeployAsync(deploymentParameters);
+
+            var response = await deploymentResult.HttpClient.GetAsync("/ServerAddresses");
+            var responseText = await response.Content.ReadAsStringAsync();
+
+            Assert.Equal(port, new Uri(responseText).Port);
+        }
+
+        private static int GetUnusedRandomPort()
+        {
+            // Port range allowed by ANCM config
+            const int minPort = 1025;
+            const int maxPort = 48000;
+
+            // Large number of retries to prevent test failures due to port collisions, but not infinite
+            // to prevent infinite loop in case Bind() fails repeatedly for some other reason.
+            const int retries = 100;
+
+            List<Exception> exceptions = null;
+
+            for (var i = 0; i < retries; i++)
+            {
+                var port = _random.Next(minPort, maxPort);
+
+                using (var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
+                {
+                    try
+                    {
+                        socket.Bind(new IPEndPoint(IPAddress.Loopback, port));
+                        return port;
+                    }
+                    catch (Exception e)
+                    {
+                        // Bind failed, most likely because port is in use.  Save exception and retry.
+                        if (exceptions == null)
+                        {
+                            exceptions = new List<Exception>(retries);
+                        }
+                        exceptions.Add(e);
+                    }
+                }
+            }
+
+            throw new AggregateException($"Unable to find unused random port after {retries} retries.", exceptions);
+        }
+    }
+}

test/WebSites/OutOfProcessWebSite/Startup.cs

@@ -11,6 +11,7 @@ using System.Threading.Tasks;
 using Microsoft.AspNetCore.Authentication;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Hosting.Server.Features;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Features;
 using Microsoft.AspNetCore.IISIntegration.FunctionalTests;
@@ -22,9 +23,13 @@ namespace TestSites
 {
     public class Startup
     {
+        private IServerAddressesFeature _serverAddresses;
+
         public void Configure(IApplicationBuilder app)
         {
             TestStartup.Register(app, this);
+
+            _serverAddresses = app.ServerFeatures.Get<IServerAddressesFeature>();
         }
 
         public Task Path(HttpContext ctx) => ctx.Response.WriteAsync(ctx.Request.Path.Value);
@@ -120,5 +125,10 @@ namespace TestSites
         {
             await context.Response.WriteAsync(Process.GetCurrentProcess().Id.ToString());
         }
+
+        private async Task ServerAddresses(HttpContext context)
+        {
+            await context.Response.WriteAsync(string.Join(",", _serverAddresses.Addresses));
+        }
     }
 }