Merge pull request #5837 from tonistiigi/dockerfile-wcow-sbom

dockerfile: fix sbom attestation for windows targets

Author: AkihiroSuda

frontend/dockerui/build.go

@@ -62,18 +62,9 @@ func (bc *Client) Build(ctx context.Context, fn BuildFunc) (*ResultBuilder, erro
 				p = platforms.DefaultSpec()
 			}
 
-			// in certain conditions we allow input platform to be extended from base image
-			if p.OS == "windows" && img.OS == p.OS {
-				if p.OSVersion == "" && img.OSVersion != "" {
-					p.OSVersion = img.OSVersion
-				}
-				if p.OSFeatures == nil && len(img.OSFeatures) > 0 {
-					p.OSFeatures = slices.Clone(img.OSFeatures)
-				}
-			}
-
-			p = platforms.Normalize(p)
 			k := platforms.FormatAll(p)
+			p = extendWindowsPlatform(p, img.Platform)
+			p = platforms.Normalize(p)
 
 			if bc.MultiPlatformRequested {
 				res.AddRef(k, ref)
@@ -129,3 +120,16 @@ func (rb *ResultBuilder) EachPlatform(ctx context.Context, fn func(ctx context.C
 	}
 	return eg.Wait()
 }
+
+func extendWindowsPlatform(p, imgP ocispecs.Platform) ocispecs.Platform {
+	// in certain conditions we allow input platform to be extended from base image
+	if p.OS == "windows" && imgP.OS == p.OS {
+		if p.OSVersion == "" && imgP.OSVersion != "" {
+			p.OSVersion = imgP.OSVersion
+		}
+		if p.OSFeatures == nil && len(imgP.OSFeatures) > 0 {
+			p.OSFeatures = slices.Clone(imgP.OSFeatures)
+		}
+	}
+	return p
+}