Fixing FSharpCompilationService file checks

Author: fabiocav

src/WebJobs.Script/Description/DotNet/FSharp/FSharpCompilationService.cs

@@ -8,13 +8,15 @@
 using System.Text;
 using System.Text.RegularExpressions;
 using System.Threading;
+using System.Threading.Tasks;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Scripting;
 using Microsoft.CodeAnalysis.Scripting.Hosting;
 using Microsoft.FSharp.Compiler;
 using Microsoft.FSharp.Compiler.SimpleSourceCodeServices;
 using Microsoft.FSharp.Compiler.SourceCodeServices;
 using Microsoft.FSharp.Core;
+using static Microsoft.Azure.WebJobs.Script.FileUtility;
 
 namespace Microsoft.Azure.WebJobs.Script.Description
 {
@@ -182,17 +184,25 @@ public ICompilation GetFunctionCompilation(FunctionMetadata functionMetadata)
                 if (code == 0)
                 {
                     var assemblyBytes = File.ReadAllBytes(dllName);
-                    var pdbBytes = File.ReadAllBytes(pdbName);
+                    byte[] pdbBytes = null;
+                    if (File.Exists(pdbName))
+                    {
+                        pdbBytes = File.ReadAllBytes(pdbName);
+                    }
                     var assembly = Assembly.Load(assemblyBytes, pdbBytes);
                     assemblyOption = FSharpOption<Assembly>.Some(assembly);
                 }
             }
             finally
             {
-                File.Delete(scriptFilePath);
-                File.Delete(dllName);
-                File.Delete(pdbName);
+                Task.WhenAll(DeleteIfExistsAsync(scriptFilePath), DeleteIfExistsAsync(dllName), DeleteIfExistsAsync(pdbName))
+                .ContinueWith(t => t.Exception.Handle(e =>
+                {
+                    // TODO: Trace
+                    return true;
+                }), TaskContinuationOptions.OnlyOnFaulted);
             }
+
             return new FSharpCompilation(errors, assemblyOption);
         }
 

src/WebJobs.Script/Extensions/FileUtility.cs

@@ -0,0 +1,26 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Microsoft.Azure.WebJobs.Script
+{
+    public static class FileUtility
+    {
+        public static Task DeleteIfExistsAsync(string path)
+        {
+            return Task.Run(() =>
+            {
+                if (File.Exists(path))
+                {
+                    File.Delete(path);
+                }
+            });
+        }
+    }
+}

src/WebJobs.Script/WebJobs.Script.csproj

@@ -408,6 +408,7 @@
     <Compile Include="EnvironmentSettingNames.cs" />
     <Compile Include="ExpandoObjectJsonConverter.cs" />
     <Compile Include="Extensions\ExceptionExtensions.cs" />
+    <Compile Include="Extensions\FileUtility.cs" />
     <Compile Include="Extensions\HttpRequestMessageExtensions.cs" />
     <Compile Include="Extensions\IDictionaryExtensions.cs" />
     <Compile Include="Extensions\IMetricsLoggerExtensions.cs" />