build: options shouldn't contain "attest:" prefix

Signed-off-by: Justin Chadwell <me@jedevc.com>

build/build.go

@@ -594,10 +594,10 @@ func toSolveOpt(ctx context.Context, node builder.Node, multiDriver bool, opt Op
 			if v == nil {
 				continue
 			}
-			so.FrontendAttrs[k] = *v
+			so.FrontendAttrs["attest:"+k] = *v
 		}
 	}
-	if _, ok := opt.Attests["attest:provenance"]; !ok {
+	if _, ok := opt.Attests["provenance"]; !ok {
 		so.FrontendAttrs["attest:provenance"] = "mode=min,inline-only=true"
 	}
 

util/buildflags/attests.go

@@ -28,14 +28,13 @@ func ParseAttests(in []string) (map[string]*string, error) {
 			return nil, err
 		}
 
-		k := "attest:" + attestType
-		if _, ok := out[k]; ok {
+		if _, ok := out[attestType]; ok {
 			return nil, errors.Errorf("duplicate attestation field %s", attestType)
 		}
 		if enabled {
-			out[k] = &in
+			out[attestType] = &in
 		} else {
-			out[k] = nil
+			out[attestType] = nil
 		}
 	}
 	return out, nil