C#: Gracefully handle non-zero exitcodes for dotnet --info.

Author: michaelnebel

csharp/autobuilder/Semmle.Autobuild.CSharp/DotNetRule.cs

@@ -48,7 +48,7 @@ public BuildScript Analyse(IAutobuilder<CSharpAutobuildOptions> builder, bool au
                 {
                     // When a custom .NET CLI has been installed, `dotnet --info` has already been executed
                     // to verify the installation.
-                    var ret = dotNetPath is null ? GetInfoCommand(builder.Actions, dotNetPath, environment) : BuildScript.Success;
+                    var ret = dotNetPath is null ? DotNet.InfoScript(builder.Actions, DotNetCommand(builder.Actions, dotNetPath), environment, builder.Logger) : BuildScript.Success;
                     foreach (var projectOrSolution in builder.ProjectsOrSolutionsToBuild)
                     {
                         var cleanCommand = GetCleanCommand(builder.Actions, dotNetPath, environment);
@@ -111,14 +111,6 @@ public static BuildScript WithDotNet(IAutobuilder<AutobuildOptionsShared> builde
         private static string DotNetCommand(IBuildActions actions, string? dotNetPath) =>
             dotNetPath is not null ? actions.PathCombine(dotNetPath, "dotnet") : "dotnet";
 
-        private static BuildScript GetInfoCommand(IBuildActions actions, string? dotNetPath, IDictionary<string, string>? environment)
-        {
-            var info = new CommandBuilder(actions, null, environment).
-                RunCommand(DotNetCommand(actions, dotNetPath)).
-                Argument("--info");
-            return info.Script;
-        }
-
         private static CommandBuilder GetCleanCommand(IBuildActions actions, string? dotNetPath, IDictionary<string, string>? environment)
         {
             var clean = new CommandBuilder(actions, null, environment).

csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DotNet.cs

@@ -3,6 +3,7 @@
 using System.Collections.ObjectModel;
 using System.IO;
 using System.Linq;
+using System.Threading;
 using Newtonsoft.Json.Linq;
 
 using Semmle.Util;
@@ -36,12 +37,29 @@ private DotNet(ILogger logger, string? dotNetPath, TemporaryDirectory tempWorkin
 
         public static IDotNet Make(ILogger logger, string? dotNetPath, TemporaryDirectory tempWorkingDirectory, DependabotProxy? dependabotProxy) => new DotNet(logger, dotNetPath, tempWorkingDirectory, dependabotProxy);
 
+        private static void HandleRetryExitCode143(string dotnet, int attempt, ILogger logger)
+        {
+            logger.LogWarning($"Running '{dotnet} --info' failed with exit code 143. Retrying...");
+            var sleep = Math.Pow(2, attempt) * 1000;
+            Thread.Sleep((int)sleep);
+        }
+
         private void Info()
         {
-            var res = dotnetCliInvoker.RunCommand("--info", silent: false);
-            if (!res)
+            // Allow up to three retry attempts to run `dotnet --info`, to mitigate transient issues
+            for (int attempt = 0; attempt < 4; attempt++)
             {
-                throw new Exception($"{dotnetCliInvoker.Exec} --info failed.");
+                var exitCode = dotnetCliInvoker.RunCommandExitCode("--info", silent: false);
+                switch (exitCode)
+                {
+                    case 0:
+                        return;
+                    case 143 when attempt < 3:
+                        HandleRetryExitCode143(dotnetCliInvoker.Exec, attempt, logger);
+                        break;
+                    default:
+                        throw new Exception($"{dotnetCliInvoker.Exec} --info failed with exit code {exitCode}.");
+                }
             }
         }
 
@@ -193,6 +211,34 @@ private static BuildScript DownloadDotNet(IBuildActions actions, ILogger logger,
             return BuildScript.Failure;
         }
 
+        /// <summary>
+        /// Returns a script for running `dotnet --info`, with retries on exit code 143.
+        /// </summary>
+        public static BuildScript InfoScript(IBuildActions actions, string dotnet, IDictionary<string, string>? environment, ILogger logger)
+        {
+            var info = new CommandBuilder(actions, null, environment).
+                RunCommand(dotnet).
+                Argument("--info");
+            var script = info.Script;
+            for (int attempt = 0; attempt < 4; attempt++)
+            {
+                script = BuildScript.Bind(script, ret =>
+                {
+                    switch (ret)
+                    {
+                        case 0:
+                            return BuildScript.Success;
+                        case 143 when attempt < 3:
+                            HandleRetryExitCode143(dotnet, attempt, logger);
+                            return info.Script;
+                        default:
+                            return BuildScript.Failure;
+                    }
+                });
+            }
+            return script;
+        }
+
         /// <summary>
         /// Returns a script for downloading specific .NET SDK versions, if the
         /// versions are not already installed.
@@ -292,9 +338,7 @@ BuildScript GetInstall(string pwsh) =>
                     };
                 }
 
-                var dotnetInfo = new CommandBuilder(actions, environment: MinimalEnvironment).
-                    RunCommand(actions.PathCombine(path, "dotnet")).
-                    Argument("--info").Script;
+                var dotnetInfo = InfoScript(actions, actions.PathCombine(path, "dotnet"), MinimalEnvironment.ToDictionary(), logger);
 
                 Func<string, BuildScript> getInstallAndVerify = version =>
                     // run `dotnet --info` after install, to check that it executes successfully

csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DotNetCliInvoker.cs

@@ -57,15 +57,21 @@ private ProcessStartInfo MakeDotnetStartInfo(string args, string? workingDirecto
             return startInfo;
         }
 
-        private bool RunCommandAux(string args, string? workingDirectory, out IList<string> output, bool silent)
+        private int RunCommandExitCodeAux(string args, string? workingDirectory, out IList<string> output, out string dirLog, bool silent)
         {
-            var dirLog = string.IsNullOrWhiteSpace(workingDirectory) ? "" : $" in {workingDirectory}";
+            dirLog = string.IsNullOrWhiteSpace(workingDirectory) ? "" : $" in {workingDirectory}";
             var pi = MakeDotnetStartInfo(args, workingDirectory);
             var threadId = Environment.CurrentManagedThreadId;
             void onOut(string s) => logger.Log(silent ? Severity.Debug : Severity.Info, s, threadId);
             void onError(string s) => logger.LogError(s, threadId);
             logger.LogInfo($"Running '{Exec} {args}'{dirLog}");
             var exitCode = pi.ReadOutput(out output, onOut, onError);
+            return exitCode;
+        }
+
+        private bool RunCommandAux(string args, string? workingDirectory, out IList<string> output, bool silent)
+        {
+            var exitCode = RunCommandExitCodeAux(args, workingDirectory, out output, out var dirLog, silent);
             if (exitCode != 0)
             {
                 logger.LogError($"Command '{Exec} {args}'{dirLog} failed with exit code {exitCode}");
@@ -77,6 +83,9 @@ private bool RunCommandAux(string args, string? workingDirectory, out IList<stri
         public bool RunCommand(string args, bool silent = true) =>
             RunCommandAux(args, null, out _, silent);
 
+        public int RunCommandExitCode(string args, bool silent = true) =>
+            RunCommandExitCodeAux(args, null, out _, out _, silent);
+
         public bool RunCommand(string args, out IList<string> output, bool silent = true) =>
             RunCommandAux(args, null, out output, silent);
 

csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/IDotNetCliInvoker.cs

@@ -30,6 +30,12 @@ internal interface IDotNetCliInvoker
         /// </summary>
         bool RunCommand(string args, bool silent = true);
 
+        /// <summary>
+        /// Execute `dotnet <paramref name="args"/>` and return the exit code.
+        /// If `silent` is true the output of the command is logged as `debug` otherwise as `info`.
+        /// </summary>
+        int RunCommandExitCode(string args, bool silent = true);
+
         /// <summary>
         /// Execute `dotnet <paramref name="args"/>` and return true if the command succeeded, otherwise false.
         /// The output of the command is returned in `output`.

csharp/extractor/Semmle.Extraction.Tests/DotNet.cs

@@ -12,6 +12,7 @@ internal class DotNetCliInvokerStub : IDotNetCliInvoker
         private string lastArgs = "";
         public string WorkingDirectory { get; private set; } = "";
         public bool Success { get; set; } = true;
+        public int ExitCode { get; set; } = 0;
 
         public DotNetCliInvokerStub(IList<string> output)
         {
@@ -26,6 +27,12 @@ public bool RunCommand(string args, bool silent)
             return Success;
         }
 
+        public int RunCommandExitCode(string args, bool silent)
+        {
+            lastArgs = args;
+            return ExitCode;
+        }
+
         public bool RunCommand(string args, out IList<string> output, bool silent)
         {
             lastArgs = args;
@@ -83,7 +90,7 @@ public void TestDotnetInfo()
         public void TestDotnetInfoFailure()
         {
             // Setup
-            var dotnetCliInvoker = new DotNetCliInvokerStub(new List<string>()) { Success = false };
+            var dotnetCliInvoker = new DotNetCliInvokerStub(new List<string>()) { ExitCode = 1 };
 
             // Execute
             try
@@ -94,7 +101,7 @@ public void TestDotnetInfoFailure()
             // Verify
             catch (Exception e)
             {
-                Assert.Equal("dotnet --info failed.", e.Message);
+                Assert.Equal("dotnet --info failed with exit code 1.", e.Message);
                 return;
             }
             Assert.Fail("Expected exception");