Fix exit code check and virtual manifest break

src/Microsoft.ComponentDetection.Detectors/rust/RustCliDetector.cs

@@ -46,7 +46,7 @@ public RustCliDetector(
     public override IEnumerable<ComponentType> SupportedComponentTypes => new[] { ComponentType.Cargo };
 
     /// <inheritdoc />
-    public override int Version => 1;
+    public override int Version => 2;
 
     /// <inheritdoc />
     public override IList<string> SearchPatterns { get; } = new[] { "Cargo.toml" };
@@ -55,6 +55,7 @@ public RustCliDetector(
     protected override async Task OnFileFoundAsync(ProcessRequest processRequest, IDictionary<string, string> detectorArgs)
     {
         var componentStream = processRequest.ComponentStream;
+        this.Logger.LogInformation("Discovered Cargo.toml: {Location}", componentStream.Location);
 
         try
         {
@@ -75,7 +76,7 @@ protected override async Task OnFileFoundAsync(ProcessRequest processRequest, ID
                 "--format-version=1",
                 "--locked");
 
-            if (cliResult.ExitCode < 0)
+            if (cliResult.ExitCode != 0)
             {
                 this.Logger.LogWarning("`cargo metadata` failed with {Location}. Ensure the Cargo.lock is up to date. stderr: {StdErr}", processRequest.ComponentStream.Location, cliResult.StdErr);
                 return;
@@ -85,6 +86,15 @@ protected override async Task OnFileFoundAsync(ProcessRequest processRequest, ID
             var graph = BuildGraph(metadata);
             var root = metadata.Resolve.Root;
 
+            // A cargo.toml can be used to declare a workspace and not a package (A Virtual Manifest).
+            // In this case, the root will be null as it will not be pulling in dependencies itself.
+            // https://doc.rust-lang.org/cargo/reference/workspaces.html#virtual-workspace
+            if (root == null)
+            {
+                this.Logger.LogWarning("Virtual Manifest: {Location}, skipping component mapping", processRequest.ComponentStream.Location);
+                return;
+            }
+
             this.TraverseAndRecordComponents(processRequest.SingleFileComponentRecorder, componentStream.Location, graph, root, null, null);
         }
         catch (InvalidOperationException e)

test/Microsoft.ComponentDetection.VerificationTests/resources/rust/standard/Cargo.toml

@@ -1,9 +1,8 @@
 [package]
-name = "component-detection"
+name = "component-detection-rust-standard"
 version = "0.1.0"
 authors = []
 edition = "2018"
-build = "build.rs"
 
 [[bin]]
 path = "main.rs"

test/Microsoft.ComponentDetection.VerificationTests/resources/rust/standard/target/.rustc_info.json

@@ -0,0 +1 @@
+{"rustc_fingerprint":6367476752289451207,"outputs":{"15729799797837862367":{"success":true,"status":"","code":0,"stdout":"___.exe\nlib___.rlib\n___.dll\n___.dll\n___.lib\n___.dll\nC:\\Users\\ferojo\\.rustup\\toolchains\\stable-x86_64-pc-windows-msvc\npacked\n___\ndebug_assertions\npanic=\"unwind\"\nproc_macro\ntarget_arch=\"x86_64\"\ntarget_endian=\"little\"\ntarget_env=\"msvc\"\ntarget_family=\"windows\"\ntarget_feature=\"fxsr\"\ntarget_feature=\"sse\"\ntarget_feature=\"sse2\"\ntarget_has_atomic=\"16\"\ntarget_has_atomic=\"32\"\ntarget_has_atomic=\"64\"\ntarget_has_atomic=\"8\"\ntarget_has_atomic=\"ptr\"\ntarget_os=\"windows\"\ntarget_pointer_width=\"64\"\ntarget_vendor=\"pc\"\nwindows\n","stderr":""},"4614504638168534921":{"success":true,"status":"","code":0,"stdout":"rustc 1.74.1 (a28077b28 2023-12-04)\nbinary: rustc\ncommit-hash: a28077b28a02b92985b3a3faecf92813155f1ea1\ncommit-date: 2023-12-04\nhost: x86_64-pc-windows-msvc\nrelease: 1.74.1\nLLVM version: 17.0.4\n","stderr":""}},"successes":{}}

test/Microsoft.ComponentDetection.VerificationTests/resources/rust/standard/target/CACHEDIR.TAG

@@ -0,0 +1,3 @@
+Signature: 8a477f597d28d172789f06886806bc55
+# This file is a cache directory tag created by cargo.
+# For information about cache directory tags see https://bford.info/cachedir/