Address PR comments.

Co-authored-by: Copilot <copilot@github.com>

Author: jpinz

src/Microsoft.ComponentDetection.Common/DockerReference/DockerReferenceUtility.cs

@@ -49,25 +49,18 @@ public static bool HasUnresolvedVariables(string reference) =>
 
     /// <summary>
     /// Attempts to parse an image reference string into a <see cref="DockerReference"/>.
-    /// Returns <c>null</c> if the reference contains unresolved variables or cannot be parsed.
+    /// Returns <c>null</c> if the reference contains unresolved variables.
     /// </summary>
     /// <param name="imageReference">The image reference string to parse.</param>
-    /// <returns>A <see cref="DockerReference"/> if parsing succeeds; otherwise <c>null</c>.</returns>
+    /// <returns>A <see cref="DockerReference"/> if parsing succeeds; otherwise <c>null</c> if it has unresolved variables, or an exception is thrown.</returns>
     public static DockerReference? TryParseImageReference(string imageReference)
     {
         if (HasUnresolvedVariables(imageReference))
         {
             return null;
         }
 
-        try
-        {
-            return ParseFamiliarName(imageReference);
-        }
-        catch
-        {
-            return null;
-        }
+        return ParseFamiliarName(imageReference);
     }
 
     /// <summary>

src/Microsoft.ComponentDetection.Detectors/dockercompose/DockerComposeComponentDetector.cs

@@ -1,4 +1,3 @@
-#nullable enable
 namespace Microsoft.ComponentDetection.Detectors.DockerCompose;
 
 using System;

src/Microsoft.ComponentDetection.Detectors/dockerfile/DockerfileComponentDetector.cs

@@ -1,4 +1,3 @@
-#nullable enable
 namespace Microsoft.ComponentDetection.Detectors.Dockerfile;
 
 using System;

test/Microsoft.ComponentDetection.Common.Tests/DockerReferenceUtilityTests.cs

@@ -296,9 +296,11 @@ public void TryParseImageReference_ReturnsNullForUnresolvedVariables()
     }
 
     [TestMethod]
-    public void TryParseImageReference_ReturnsNullForInvalidReference()
+    public void TryParseImageReference_ThrowsForInvalidReference()
     {
-        DockerReferenceUtility.TryParseImageReference("docker.io/library/Nginx").Should().BeNull();
+        var func = () => DockerReferenceUtility.TryParseImageReference("docker.io/library/Nginx");
+
+        func.Should().Throw<ReferenceNameContainsUppercaseException>();
     }
 
     [TestMethod]
@@ -355,12 +357,13 @@ public void TryRegisterImageReference_SkipsUnresolvedVariables()
     }
 
     [TestMethod]
-    public void TryRegisterImageReference_SkipsInvalidReference()
+    public void TryRegisterImageReference_ThrowsForInvalidReference()
     {
         var recorder = new Mock<ISingleFileComponentRecorder>();
 
-        DockerReferenceUtility.TryRegisterImageReference("docker.io/library/Nginx", recorder.Object);
+        var func = () => DockerReferenceUtility.TryRegisterImageReference("docker.io/library/Nginx", recorder.Object);
 
+        func.Should().Throw<ReferenceNameContainsUppercaseException>();
         recorder.Verify(r => r.RegisterUsage(It.IsAny<DetectedComponent>(), It.IsAny<bool>(), It.IsAny<string>(), It.IsAny<bool?>(), It.IsAny<DependencyScope?>(), It.IsAny<string>()), Times.Never);
     }
 }