Enable nullable in Linux detector files (#1709)

jasonpaulos · web-flow · commit f2d7419f9ddd · 2026-03-10T13:20:57.000-04:00
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/Contracts/ImageScanningResult.cs b/src/Microsoft.ComponentDetection.Detectors/linux/Contracts/ImageScanningResult.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux.Contracts;
 
 using System.Collections.Generic;
@@ -13,10 +12,10 @@ internal class ImageScanningResult
     /// <summary>
     /// Gets or sets the container details associated with the image scanning result.
     /// </summary>
-    public ContainerDetails ContainerDetails { get; set; }
+    public ContainerDetails? ContainerDetails { get; set; }
 
     /// <summary>
     /// Gets or sets the collection of components detected during the image scanning process.
     /// </summary>
-    public IEnumerable<DetectedComponent> Components { get; set; }
+    public IEnumerable<DetectedComponent> Components { get; set; } = [];
 }
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/Exceptions/MissingContainerDetailException.cs b/src/Microsoft.ComponentDetection.Detectors/linux/Exceptions/MissingContainerDetailException.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux.Exceptions;
 
 using System;
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/Factories/ArtifactComponentFactoryBase.cs b/src/Microsoft.ComponentDetection.Detectors/linux/Factories/ArtifactComponentFactoryBase.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux.Factories;
 
 using System.Collections.Generic;
@@ -19,14 +18,14 @@ public abstract class ArtifactComponentFactoryBase : IArtifactComponentFactory
     public abstract IEnumerable<string> SupportedArtifactTypes { get; }
 
     /// <inheritdoc/>
-    public abstract TypedComponent CreateComponent(ArtifactElement artifact, Distro distro);
+    public abstract TypedComponent? CreateComponent(ArtifactElement artifact, Distro distro);
 
     /// <summary>
     /// Extracts license information from the artifact, checking both metadata and top-level licenses array.
     /// </summary>
     /// <param name="artifact">The artifact element from Syft output.</param>
     /// <returns>A comma-separated string of license values, or null if no licenses are found.</returns>
-    protected static string GetLicenseFromArtifact(ArtifactElement artifact)
+    protected static string? GetLicenseFromArtifact(ArtifactElement artifact)
     {
         // First try metadata.License which may be a string
         var license = artifact.Metadata?.License?.String;
@@ -50,7 +49,7 @@ protected static string GetLicenseFromArtifact(ArtifactElement artifact)
     /// </summary>
     /// <param name="artifact">The artifact element from Syft output.</param>
     /// <returns>The author or maintainer string, or null if neither is found.</returns>
-    protected static string GetAuthorFromArtifact(ArtifactElement artifact)
+    protected static string? GetAuthorFromArtifact(ArtifactElement artifact)
     {
         var author = artifact.Metadata?.Author;
         if (!string.IsNullOrEmpty(author))
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/Factories/CargoComponentFactory.cs b/src/Microsoft.ComponentDetection.Detectors/linux/Factories/CargoComponentFactory.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux.Factories;
 
 using System.Collections.Generic;
@@ -17,7 +16,7 @@ internal class CargoComponentFactory : ArtifactComponentFactoryBase
     public override IEnumerable<string> SupportedArtifactTypes => ["rust-crate"];
 
     /// <inheritdoc/>
-    public override TypedComponent CreateComponent(ArtifactElement artifact, Distro distro)
+    public override TypedComponent? CreateComponent(ArtifactElement artifact, Distro distro)
     {
         if (artifact == null)
         {
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/Factories/CondaComponentFactory.cs b/src/Microsoft.ComponentDetection.Detectors/linux/Factories/CondaComponentFactory.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux.Factories;
 
 using System.Collections.Generic;
@@ -17,7 +16,7 @@ internal class CondaComponentFactory : ArtifactComponentFactoryBase
     public override IEnumerable<string> SupportedArtifactTypes => ["conda"];
 
     /// <inheritdoc/>
-    public override TypedComponent CreateComponent(ArtifactElement artifact, Distro distro)
+    public override TypedComponent? CreateComponent(ArtifactElement artifact, Distro distro)
     {
         if (artifact == null)
         {
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/Factories/GoComponentFactory.cs b/src/Microsoft.ComponentDetection.Detectors/linux/Factories/GoComponentFactory.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux.Factories;
 
 using System.Collections.Generic;
@@ -17,7 +16,7 @@ internal class GoComponentFactory : ArtifactComponentFactoryBase
     public override IEnumerable<string> SupportedArtifactTypes => ["go-module"];
 
     /// <inheritdoc/>
-    public override TypedComponent CreateComponent(ArtifactElement artifact, Distro distro)
+    public override TypedComponent? CreateComponent(ArtifactElement artifact, Distro distro)
     {
         if (artifact == null)
         {
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/Factories/IArtifactComponentFactory.cs b/src/Microsoft.ComponentDetection.Detectors/linux/Factories/IArtifactComponentFactory.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux.Factories;
 
 using System.Collections.Generic;
@@ -30,5 +29,5 @@ public interface IArtifactComponentFactory
     /// <param name="artifact">The artifact element from Syft output.</param>
     /// <param name="distro">The distribution information from Syft output.</param>
     /// <returns>A TypedComponent instance, or null if the artifact cannot be processed.</returns>
-    public TypedComponent CreateComponent(ArtifactElement artifact, Distro distro);
+    public TypedComponent? CreateComponent(ArtifactElement artifact, Distro distro);
 }
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/Factories/LinuxComponentFactory.cs b/src/Microsoft.ComponentDetection.Detectors/linux/Factories/LinuxComponentFactory.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux.Factories;
 
 using System.Collections.Generic;
@@ -17,7 +16,7 @@ internal class LinuxComponentFactory : ArtifactComponentFactoryBase
     public override IEnumerable<string> SupportedArtifactTypes => ["apk", "deb", "rpm"];
 
     /// <inheritdoc/>
-    public override TypedComponent CreateComponent(ArtifactElement artifact, Distro distro)
+    public override TypedComponent? CreateComponent(ArtifactElement artifact, Distro distro)
     {
         if (artifact == null || distro == null)
         {
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/Factories/MavenComponentFactory.cs b/src/Microsoft.ComponentDetection.Detectors/linux/Factories/MavenComponentFactory.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux.Factories;
 
 using System.Collections.Generic;
@@ -17,7 +16,7 @@ internal class MavenComponentFactory : ArtifactComponentFactoryBase
     public override IEnumerable<string> SupportedArtifactTypes => ["java-archive"];
 
     /// <inheritdoc/>
-    public override TypedComponent CreateComponent(ArtifactElement artifact, Distro distro)
+    public override TypedComponent? CreateComponent(ArtifactElement artifact, Distro distro)
     {
         if (artifact == null)
         {
@@ -59,7 +58,7 @@ public override TypedComponent CreateComponent(ArtifactElement artifact, Distro
     /// Attempts to parse groupId and artifactId from a name in the format "groupId:artifactId"
     /// or similar Maven coordinate notation.
     /// </summary>
-    private static bool TryParseFromName(string name, out string groupId, out string artifactId)
+    private static bool TryParseFromName(string name, out string? groupId, out string? artifactId)
     {
         groupId = null;
         artifactId = null;
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/Factories/NpmComponentFactory.cs b/src/Microsoft.ComponentDetection.Detectors/linux/Factories/NpmComponentFactory.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux.Factories;
 
 using System.Collections.Generic;
@@ -18,7 +17,7 @@ internal class NpmComponentFactory : ArtifactComponentFactoryBase
     public override IEnumerable<string> SupportedArtifactTypes => ["npm"];
 
     /// <inheritdoc/>
-    public override TypedComponent CreateComponent(ArtifactElement artifact, Distro distro)
+    public override TypedComponent? CreateComponent(ArtifactElement artifact, Distro distro)
     {
         if (artifact == null)
         {
@@ -41,7 +40,7 @@ public override TypedComponent CreateComponent(ArtifactElement artifact, Distro
         );
     }
 
-    private static NpmAuthor GetNpmAuthorFromArtifact(ArtifactElement artifact)
+    private static NpmAuthor? GetNpmAuthorFromArtifact(ArtifactElement artifact)
     {
         var authorString = artifact.Metadata?.Author;
         if (!string.IsNullOrWhiteSpace(authorString))
@@ -52,7 +51,7 @@ private static NpmAuthor GetNpmAuthorFromArtifact(ArtifactElement artifact)
         return null;
     }
 
-    private static string GetHashFromArtifact(ArtifactElement artifact)
+    private static string? GetHashFromArtifact(ArtifactElement artifact)
     {
         if (!string.IsNullOrWhiteSpace(artifact.Metadata?.Integrity))
         {
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/Factories/PipComponentFactory.cs b/src/Microsoft.ComponentDetection.Detectors/linux/Factories/PipComponentFactory.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux.Factories;
 
 using System.Collections.Generic;
@@ -17,7 +16,7 @@ internal class PipComponentFactory : ArtifactComponentFactoryBase
     public override IEnumerable<string> SupportedArtifactTypes => ["python"];
 
     /// <inheritdoc/>
-    public override TypedComponent CreateComponent(ArtifactElement artifact, Distro distro)
+    public override TypedComponent? CreateComponent(ArtifactElement artifact, Distro distro)
     {
         if (artifact == null)
         {
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/Factories/PodComponentFactory.cs b/src/Microsoft.ComponentDetection.Detectors/linux/Factories/PodComponentFactory.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux.Factories;
 
 using System.Collections.Generic;
@@ -17,7 +16,7 @@ internal class PodComponentFactory : ArtifactComponentFactoryBase
     public override IEnumerable<string> SupportedArtifactTypes => ["pod"];
 
     /// <inheritdoc/>
-    public override TypedComponent CreateComponent(ArtifactElement artifact, Distro distro)
+    public override TypedComponent? CreateComponent(ArtifactElement artifact, Distro distro)
     {
         if (artifact == null)
         {
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/Factories/RubyGemsComponentFactory.cs b/src/Microsoft.ComponentDetection.Detectors/linux/Factories/RubyGemsComponentFactory.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux.Factories;
 
 using System.Collections.Generic;
@@ -17,7 +16,7 @@ internal class RubyGemsComponentFactory : ArtifactComponentFactoryBase
     public override IEnumerable<string> SupportedArtifactTypes => ["gem"];
 
     /// <inheritdoc/>
-    public override TypedComponent CreateComponent(ArtifactElement artifact, Distro distro)
+    public override TypedComponent? CreateComponent(ArtifactElement artifact, Distro distro)
     {
         if (artifact == null)
         {
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/ILinuxScanner.cs b/src/Microsoft.ComponentDetection.Detectors/linux/ILinuxScanner.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux;
 
 using System.Collections.Generic;
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/LinuxApplicationLayerDetector.cs b/src/Microsoft.ComponentDetection.Detectors/linux/LinuxApplicationLayerDetector.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux;
 
 using System;
@@ -27,16 +26,16 @@ ILogger<LinuxApplicationLayerDetector> logger
     /// <inheritdoc/>
     public new IEnumerable<string> Categories =>
         [
-            Enum.GetName(typeof(DetectorClass), DetectorClass.Linux),
-            Enum.GetName(typeof(DetectorClass), DetectorClass.Cargo),
-            Enum.GetName(typeof(DetectorClass), DetectorClass.CocoaPods),
-            Enum.GetName(typeof(DetectorClass), DetectorClass.Conda),
-            Enum.GetName(typeof(DetectorClass), DetectorClass.GoMod),
-            Enum.GetName(typeof(DetectorClass), DetectorClass.Maven),
-            Enum.GetName(typeof(DetectorClass), DetectorClass.Npm),
-            Enum.GetName(typeof(DetectorClass), DetectorClass.NuGet),
-            Enum.GetName(typeof(DetectorClass), DetectorClass.Pip),
-            Enum.GetName(typeof(DetectorClass), DetectorClass.RubyGems),
+            Enum.GetName(typeof(DetectorClass), DetectorClass.Linux)!,
+            Enum.GetName(typeof(DetectorClass), DetectorClass.Cargo)!,
+            Enum.GetName(typeof(DetectorClass), DetectorClass.CocoaPods)!,
+            Enum.GetName(typeof(DetectorClass), DetectorClass.Conda)!,
+            Enum.GetName(typeof(DetectorClass), DetectorClass.GoMod)!,
+            Enum.GetName(typeof(DetectorClass), DetectorClass.Maven)!,
+            Enum.GetName(typeof(DetectorClass), DetectorClass.Npm)!,
+            Enum.GetName(typeof(DetectorClass), DetectorClass.NuGet)!,
+            Enum.GetName(typeof(DetectorClass), DetectorClass.Pip)!,
+            Enum.GetName(typeof(DetectorClass), DetectorClass.RubyGems)!,
         ];
 
     /// <inheritdoc/>
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/LinuxContainerDetector.cs b/src/Microsoft.ComponentDetection.Detectors/linux/LinuxContainerDetector.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux;
 
 using System;
@@ -40,7 +39,7 @@ ILogger<LinuxContainerDetector> logger
 
     /// <inheritdoc/>
     public IEnumerable<string> Categories =>
-        [Enum.GetName(typeof(DetectorClass), DetectorClass.Linux)];
+        [Enum.GetName(typeof(DetectorClass), DetectorClass.Linux)!];
 
     /// <inheritdoc/>
     public IEnumerable<ComponentType> SupportedComponentTypes => [ComponentType.Linux];
@@ -226,8 +225,7 @@ await this.dockerService.ImageExistsLocallyAsync(image, cancellationToken)
                 )
                 {
                     throw new InvalidUserInputException(
-                        $"Container image {image} could not be found locally and could not be pulled. Verify the image is either available locally or can be pulled from a registry.",
-                        null
+                        $"Container image {image} could not be found locally and could not be pulled. Verify the image is either available locally or can be pulled from a registry."
                     );
                 }
 
diff --git a/src/Microsoft.ComponentDetection.Detectors/linux/LinuxScanner.cs b/src/Microsoft.ComponentDetection.Detectors/linux/LinuxScanner.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Linux;
 
 using System;
@@ -196,6 +195,7 @@ public async Task<IEnumerable<LayerMappedLinuxComponents>> ScanLinuxAsync(
                     this.CreateComponentWithLayers(artifact, syftOutput.Distro, enabledFactories)
                 )
                 .Where(result => result.Component != null)
+                .Select(result => (Component: result.Component!, result.LayerIds))
                 .ToList();
 
             // Track unsupported artifact types for telemetry
@@ -239,11 +239,11 @@ public async Task<IEnumerable<LayerMappedLinuxComponents>> ScanLinuxAsync(
         catch (Exception e)
         {
             record.FailedDeserializingScannerOutput = e.ToString();
-            return null;
+            return [];
         }
     }
 
-    private (TypedComponent Component, IEnumerable<string> LayerIds) CreateComponentWithLayers(
+    private (TypedComponent? Component, IEnumerable<string> LayerIds) CreateComponentWithLayers(
         ArtifactElement artifact,
         Distro distro,
         HashSet<IArtifactComponentFactory> enabledFactories
diff --git a/test/Microsoft.ComponentDetection.Detectors.Tests/LinuxContainerDetectorTests.cs b/test/Microsoft.ComponentDetection.Detectors.Tests/LinuxContainerDetectorTests.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Tests;
 
 using System;
@@ -160,7 +159,7 @@ public async Task TestLinuxContainerDetector_CantRunLinuxContainersAsync()
                 It.IsAny<EventId>(),
                 It.IsAny<It.IsAnyType>(),
                 It.IsAny<Exception>(),
-                (Func<It.IsAnyType, Exception, string>)It.IsAny<object>()
+                (Func<It.IsAnyType, Exception?, string>)It.IsAny<object>()
             )
         );
     }
@@ -198,7 +197,7 @@ public async Task TestLinuxContainerDetector_TestNullAsync()
                 It.IsAny<EventId>(),
                 It.IsAny<It.IsAnyType>(),
                 It.IsAny<Exception>(),
-                (Func<It.IsAnyType, Exception, string>)It.IsAny<object>()
+                (Func<It.IsAnyType, Exception?, string>)It.IsAny<object>()
             )
         );
     }
diff --git a/test/Microsoft.ComponentDetection.Detectors.Tests/LinuxScannerTests.cs b/test/Microsoft.ComponentDetection.Detectors.Tests/LinuxScannerTests.cs
@@ -1,4 +1,3 @@
-#nullable disable
 namespace Microsoft.ComponentDetection.Detectors.Tests;
 
 using System;
@@ -297,7 +296,9 @@ await this.linuxScanner.ScanLinuxAsync(
             .Components;
 
         result.Should().ContainSingle();
+        result.First().Should().BeOfType<LinuxComponent>();
         var package = result.First() as LinuxComponent;
+        package.Should().NotBeNull();
         package.Name.Should().Be("test");
         package.Version.Should().Be("1.0.0");
         package.Release.Should().Be("1.0.0");
@@ -345,7 +346,9 @@ await this.linuxScanner.ScanLinuxAsync(
             .Components;
 
         result.Should().ContainSingle();
+        result.First().Should().BeOfType<LinuxComponent>();
         var package = result.First() as LinuxComponent;
+        package.Should().NotBeNull();
         package.Name.Should().Be("test");
         package.Version.Should().Be("1.0.0");
         package.Release.Should().Be("1.0.0");
@@ -395,7 +398,9 @@ await this.linuxScanner.ScanLinuxAsync(
             .Components;
 
         result.Should().ContainSingle();
+        result.First().Should().BeOfType<LinuxComponent>();
         var package = result.First() as LinuxComponent;
+        package.Should().NotBeNull();
         package.Name.Should().Be("busybox");
         package.Version.Should().Be("1.35.0-13.cm2");
         package.Release.Should().Be("2.0");
diff --git a/test/Microsoft.ComponentDetection.Orchestrator.Tests/Experiments/LinuxApplicationLayerExperimentTests.cs b/test/Microsoft.ComponentDetection.Orchestrator.Tests/Experiments/LinuxApplicationLayerExperimentTests.cs

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,3 @@`
`1`		`-#nullable disable`
`2`	`1`	`namespace Microsoft.ComponentDetection.Detectors.Linux.Exceptions;`
`3`	`2`
`4`	`3`	`using System;`