Emit Warning When Using CLI Switches from Auto-Response File Lead to Errors

src/MSBuild.UnitTests/XMake_Tests.cs

@@ -1571,6 +1571,23 @@ public void ResponseFileInProjectDirectoryWithSolutionProjectDifferentNamesShoul
             successfulExit.ShouldBeTrue();
         }
 
+        [Fact]
+        public void ResponseFileNoticeIsPrintedOnSwitchError()
+        {
+            var directory = _env.CreateFolder();
+            var content = ObjectModelHelpers.CleanupFileContents("<Project><Target Name='t'><Message Text='Completed'/></Target></Project>");
+            directory.CreateFile("foo.proj", content);
+            var projectPath = directory.CreateFile("bar.proj", content).Path;
+            var rspPath = directory.CreateFile("Directory.Build.rsp", "foo.proj").Path;
+
+            string output = RunnerUtilities.ExecMSBuild($"\"{projectPath}\"", out var successfulExit, _output);
+
+            successfulExit.ShouldBeFalse();
+            output.ShouldContain("Some command line switches were read from the auto-response file");
+            output.ShouldContain(rspPath);
+            output.ShouldContain("MSB1008");
+        }
+
         /// <summary>
         /// Any msbuild.rsp in the directory of the specified project/solution should be read, and should
         /// take priority over any other response files. Sanity test when there isn't one.

src/MSBuild/XMake.cs

@@ -937,6 +937,11 @@ public static ExitType Execute(string[] commandLine)
             // handle switch errors
             catch (CommandLineSwitchException e)
             {
+                if (commandLineParser.IncludedResponseFiles.Count > 0)
+                {
+                    PrintResponseFileNotices();
+                }
+
                 Console.WriteLine(e.Message);
                 Console.WriteLine();
                 // prompt user to display help for proper switch usage
@@ -4209,6 +4214,17 @@ private static void ShowHelpPrompt()
             Console.WriteLine(AssemblyResources.GetString("HelpPrompt"));
         }
 
+        private static void PrintResponseFileNotices()
+        {
+            foreach (string responseFilePath in commandLineParser.IncludedResponseFiles)
+            {
+                Console.WriteLine(
+                    ResourceUtilities.FormatResourceStringIgnoreCodeAndKeyword(
+                        "PickedUpSwitchesFromAutoResponse",
+                        responseFilePath));
+            }
+        }
+
         /// <summary>
         /// Displays the build engine's version number.
         /// </summary>