fix(crafter): surface auto-discovery validation errors

Stop probing material kinds when auto-detection hits a protovalidate
ValidationError. Schema-level failures, such as invalid material names,
are not kind mismatches and should be surfaced directly.

Fixes: #2394

Assisted-by: pi
Signed-off-by: Vibhav Bobade <vibhav.bobde@gmail.com>

Author: waveywaves

pkg/attestation/crafter/crafter.go

@@ -653,31 +653,33 @@ func (c *Crafter) IsMaterialInContract(key string) bool {
 // AddMaterialContactFreeWithAutoDetectedKind adds a material to the crafting state checking the incoming material matches any of the
 // supported types in validation order. If the material is not found it will return an error.
 func (c *Crafter) AddMaterialContactFreeWithAutoDetectedKind(ctx context.Context, attestationID, name, value string, casBackend *casclient.CASBackend, runtimeAnnotations map[string]string, opts ...AddOpt) (*api.Attestation_Material, error) {
-	var err error
 	for _, kind := range schemaapi.CraftingMaterialInValidationOrder {
 		m, err := c.AddMaterialContractFree(ctx, attestationID, kind.String(), name, value, casBackend, runtimeAnnotations, opts...)
 		if err == nil {
-			// Successfully added material, return the kind
 			return m, nil
 		}
 
 		c.Logger.Debug().Err(err).Str("kind", kind.String()).Msg("failed to add material")
 
-		// Handle base error for upload and craft errors except the opening file error
-		// TODO: have an error to detect validation error instead
 		var policyError *policies.PolicyError
 		if errors.Is(err, materials.ErrBaseUploadAndCraft) || errors.As(err, &policyError) {
 			return nil, err
 		}
 
-		// This is a final error, we detected the kind
 		if v1.IsAttestationStateErrorConflict(err) {
 			return nil, err
 		}
+
+		// Proto-validation errors (e.g. invalid material name) are schema-level
+		// failures, not kind mismatches. Stop probing immediately so the real
+		// error is surfaced to the user instead of being masked by the loop.
+		var valErr *protovalidate.ValidationError
+		if errors.As(err, &valErr) {
+			return nil, err
+		}
 	}
 
-	// Return an error if no material could be added
-	return nil, fmt.Errorf("failed to auto-discover material kind: %w", err)
+	return nil, errors.New("failed to auto-discover material kind")
 }
 
 // addMaterials adds the incoming material m to the crafting state

pkg/attestation/crafter/crafter_test.go

@@ -672,6 +672,20 @@ func (s *crafterSuite) TestAddMaterialsAutomatic() {
 	}
 }
 
+func (s *crafterSuite) TestAddMaterialsAutomaticInvalidNameSurfacesValidationError() {
+	var runner crafter.SupportedRunner = runners.NewGeneric()
+	uploader := mUploader.NewUploader(s.T())
+
+	c, err := newInitializedCrafter(s.T(), "testdata/contracts/empty_generic.yaml", &v1.WorkflowMetadata{}, false, "", runner)
+	require.NoError(s.T(), err)
+
+	m, err := c.AddMaterialContactFreeWithAutoDetectedKind(context.Background(), "random-id", "invalid_name", "./materials/testdata/junit.xml", &casclient.CASBackend{Uploader: uploader}, nil)
+	require.Error(s.T(), err)
+	assert.Nil(s.T(), m)
+	assert.Contains(s.T(), err.Error(), "must contain only lowercase letters, numbers, and hyphens")
+	assert.NotContains(s.T(), err.Error(), "failed to auto-discover material kind")
+}
+
 func loadSchema(path string) (*schemaapi.CraftingSchema, error) {
 	// Extract json formatted data
 	content, err := os.ReadFile(filepath.Clean(path))