C#: Add high level diagnostic messages for buildless extraction (start, success)

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

@@ -44,7 +44,7 @@ namespace Semmle.Autobuild.CSharp
         public override BuildScript GetBuildScript()
         {
             var attempt = BuildScript.Failure;
-            switch (GetCSharpBuildStrategy())
+            switch (BuildStrategy)
             {
                 case CSharpBuildStrategy.CustomBuildCommand:
                     attempt = new BuildCommandRule(DotNetRule.WithDotNet).Analyse(this, false) & CheckExtractorRun(true);
@@ -218,6 +218,10 @@ namespace Semmle.Autobuild.CSharp
             return CSharpBuildStrategy.Auto;
         }
 
+        private CSharpBuildStrategy? buildStrategy = null;
+        private CSharpBuildStrategy BuildStrategy => buildStrategy ??= GetCSharpBuildStrategy();
+        public override bool IsBuildless => BuildStrategy == CSharpBuildStrategy.Buildless;
+
         private enum CSharpBuildStrategy
         {
             CustomBuildCommand,

csharp/autobuilder/Semmle.Autobuild.Shared/Autobuilder.cs

@@ -301,6 +301,18 @@ namespace Semmle.Autobuild.Shared
             var onOutput = BuildOutputHandler(Console.Out);
             var onError = BuildOutputHandler(Console.Error);
 
+            if (IsBuildless)
+            {
+                AddDiagnostic(new DiagnosticMessage(
+                    Options.Language,
+                    "buildless/mode-active",
+                    "C# was extracted in buildless mode",
+                    visibility: new DiagnosticMessage.TspVisibility(statusPage: true, cliSummaryTable: true, telemetry: true),
+                    markdownMessage: "C# was extracted in buildless mode. This means that all C# source in the working directory will be scanned, with build tools, such as Nuget and Dotnet CLIs, only contributing information about external dependencies.",
+                    severity: DiagnosticMessage.TspSeverity.Note
+                ));
+            }
+
             var buildResult = script.Run(Actions, startCallback, exitCallback, onOutput, onError);
 
             // if the build succeeded, all diagnostics we captured from the build output should be warnings;
@@ -310,6 +322,18 @@ namespace Semmle.Autobuild.Shared
                 .Select(result => result.ToDiagnosticMessage(this, diagSeverity))
                 .ForEach(AddDiagnostic);
 
+            if (buildResult == 0 && IsBuildless)
+            {
+                AddDiagnostic(new DiagnosticMessage(
+                    Options.Language,
+                    "buildless/complete",
+                    "C# buildless extraction completed",
+                    visibility: new DiagnosticMessage.TspVisibility(statusPage: false, cliSummaryTable: true, telemetry: true),
+                    markdownMessage: "C# buildless extraction has completed.",
+                    severity: DiagnosticMessage.TspSeverity.Unknown
+                ));
+            }
+
             return buildResult;
         }
 
@@ -318,6 +342,8 @@ namespace Semmle.Autobuild.Shared
         /// </summary>
         public abstract BuildScript GetBuildScript();
 
+        public virtual bool IsBuildless { get; } = false;
+
 
         /// <summary>
         /// Produces a diagnostic for the tool status page that we were unable to automatically

csharp/extractor/Semmle.Util/ToolStatusPage.cs

@@ -46,6 +46,7 @@ namespace Semmle.Util
         [JsonConverter(typeof(StringEnumConverter), typeof(CamelCaseNamingStrategy))]
         public enum TspSeverity
         {
+            Unknown,
             Note,
             Warning,
             Error

csharp/ql/integration-tests/all-platforms/standalone/diagnostics.expected

@@ -0,0 +1,28 @@
+{
+  "markdownMessage": "C# buildless extraction has completed.",
+  "severity": "unknown",
+  "source": {
+    "extractorName": "csharp",
+    "id": "csharp/autobuilder/buildless/complete",
+    "name": "C# buildless extraction completed"
+  },
+  "visibility": {
+    "cliSummaryTable": true,
+    "statusPage": false,
+    "telemetry": true
+  }
+}
+{
+  "markdownMessage": "C# was extracted in buildless mode. This means that all C# source in the working directory will be scanned, with build tools, such as Nuget and Dotnet CLIs, only contributing information about external dependencies.",
+  "severity": "note",
+  "source": {
+    "extractorName": "csharp",
+    "id": "csharp/autobuilder/buildless/mode-active",
+    "name": "C# was extracted in buildless mode"
+  },
+  "visibility": {
+    "cliSummaryTable": true,
+    "statusPage": true,
+    "telemetry": true
+  }
+}

csharp/ql/integration-tests/all-platforms/standalone/test.py

@@ -1,3 +1,6 @@
 from create_database_utils import *
+from diagnostics_test_utils import *
 
 run_codeql_database_create([], lang="csharp", extra_args=["--build-mode=none"])
+
+check_diagnostics()