null check

Author: pauld-msft

src/Microsoft.ComponentDetection.Detectors/linux/LinuxContainerDetector.cs

@@ -662,12 +662,24 @@ await this.dockerService.ImageExistsLocallyAsync(refWithDigest, cancellationToke
             refWithDigest,
             cancellationToken
         );
+
+        if (baseImageDetails == null)
+        {
+            record.BaseImageLayerMessage = "Failed to inspect base image after pull";
+            this.logger.LogInformation(
+                "Failed to inspect base image {BaseImage} after pull. Results will not be mapped to base image layers",
+                refWithDigest
+            );
+            return 0;
+        }
+
         this.logger.LogDebug(
             "Base image {BaseImage} resolved for {ContainerImage} with {LayerCount} layers",
             refWithDigest,
             image,
             baseImageDetails.Layers.Count()
         );
+
         if (!ValidateBaseImageLayers(scannedImageDetails, baseImageDetails))
         {
             record.BaseImageLayerMessage =