Merge pull request github#13030 from hvitved/csharp/warn-as-error

C#: Never treat warnings as error in the extractor

Author: hvitved

csharp/extractor/Semmle.Extraction.CSharp/Extractor/CompilerVersion.cs

@@ -130,9 +130,14 @@ public bool SkipExtraction
         /// <returns>Modified list of arguments.</returns>
         private static IEnumerable<string> AddDefaultResponse(string responseFile, IEnumerable<string> args)
         {
-            return SuppressDefaultResponseFile(args) || !File.Exists(responseFile) ?
+            var ret = SuppressDefaultResponseFile(args) || !File.Exists(responseFile) ?
                 args :
                 new[] { "@" + responseFile }.Concat(args);
+
+            // make sure to never treat warnings as errors in the extractor:
+            // our version of Roslyn may report warnings that the actual build
+            // doesn't
+            return ret.Concat(new[] { "/warnaserror-" });
         }
 
         private static bool SuppressDefaultResponseFile(IEnumerable<string> args)

csharp/ql/integration-tests/posix-only/warn_as_error/Errors.expected

@@ -0,0 +1,6 @@
+import csharp
+import semmle.code.csharp.commons.Diagnostics
+
+from Diagnostic d
+where d.getSeverity() >= 3
+select d

csharp/ql/integration-tests/posix-only/warn_as_error/Errors.ql

@@ -0,0 +1,4 @@
+// See https://aka.ms/new-console-template for more information
+Console.WriteLine("Hello, World!");
+
+var x = "unused";

csharp/ql/integration-tests/posix-only/warn_as_error/Program.cs

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net7.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+  </PropertyGroup>
+
+</Project>

csharp/ql/integration-tests/posix-only/warn_as_error/WarnAsError.csproj

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+# Will fail because of a warning
+dotnet build
+
+# Pretend it didn't fail, so extraction succeeds (which doesn't treat warnings as errors)
+exit 0

csharp/ql/integration-tests/posix-only/warn_as_error/build.sh

@@ -0,0 +1,7 @@
+import os
+from create_database_utils import *
+from diagnostics_test_utils import *
+
+run_codeql_database_create(["./build.sh"], lang="csharp", extra_args=["--extractor-option=cil=false"])
+
+check_diagnostics()