Make errors regarding chart.yaml metadata clear

Signed-off-by: Karuppiah Natarajan <karuppiah7890@gmail.com>

cmd/helm/testdata/output/install-chart-bad-type.txt

@@ -1 +1 @@
-Error: validation: chart.metadata.type must be application or library
+Error: validation: chart.metadata.type must be 'application' or 'library' in Chart.yaml

cmd/helm/testdata/output/template-lib-chart.txt

@@ -1 +1 @@
-Error: validation: chart.metadata.type must be application or library
+Error: validation: chart.metadata.type must be 'application' or 'library' in Chart.yaml

pkg/chart/errors.go

@@ -15,9 +15,19 @@ limitations under the License.
 
 package chart
 
-// ValidationError represents a data validation error.
-type ValidationError string
+import "github.com/pkg/errors"
 
-func (v ValidationError) Error() string {
-	return "validation: " + string(v)
-}
+// ErrMissingMetadata indicates that Chart.yaml is missing
+var ErrMissingMetadata = errors.New("validation: chart.metadata (Chart.yaml) is required")
+
+// ErrMissingAPIVersion indicates that chart apiVersion is missing in Chart.yaml
+var ErrMissingAPIVersion = errors.New("validation: chart.metadata.apiVersion is required in Chart.yaml")
+
+// ErrMissingName indicates that chart name is missing in Chart.yaml
+var ErrMissingName = errors.New("validation: chart.metadata.name is required in Chart.yaml")
+
+// ErrMissingVersion indicates that chart version is missing in Chart.yaml
+var ErrMissingVersion = errors.New("validation: chart.metadata.version is required in Chart.yaml")
+
+// ErrInvalidType indicates that chart type is invalid in Chart.yaml
+var ErrInvalidType = errors.New("validation: chart.metadata.type must be 'application' or 'library' in Chart.yaml")

pkg/chart/loader/load_test.go

@@ -130,8 +130,8 @@ icon: https://example.com/64x64.png
 	if _, err = LoadFiles([]*BufferedFile{}); err == nil {
 		t.Fatal("Expected err to be non-nil")
 	}
-	if err.Error() != "validation: chart.metadata is required" {
-		t.Errorf("Expected chart metadata missing error, got '%s'", err.Error())
+	if err != chart.ErrMissingMetadata {
+		t.Errorf("Expected '%s', got '%s'", chart.ErrMissingMetadata.Error(), err.Error())
 	}
 }
 

pkg/chart/metadata.go

@@ -64,21 +64,22 @@ type Metadata struct {
 	Type string `json:"type,omitempty"`
 }
 
+// Validate validates the Chart.yaml contents
 func (md *Metadata) Validate() error {
 	if md == nil {
-		return ValidationError("chart.metadata is required")
+		return ErrMissingMetadata
 	}
 	if md.APIVersion == "" {
-		return ValidationError("chart.metadata.apiVersion is required")
+		return ErrMissingAPIVersion
 	}
 	if md.Name == "" {
-		return ValidationError("chart.metadata.name is required")
+		return ErrMissingName
 	}
 	if md.Version == "" {
-		return ValidationError("chart.metadata.version is required")
+		return ErrMissingVersion
 	}
 	if !isValidChartType(md.Type) {
-		return ValidationError("chart.metadata.type must be application or library")
+		return ErrInvalidType
 	}
 	// TODO validate valid semver here?
 	return nil

pkg/chart/metadata_test.go

@@ -0,0 +1,87 @@
+/*
+Copyright The Helm Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package chart
+
+import (
+	"testing"
+)
+
+func TestMetadata_Validate(t *testing.T) {
+	t.Run("return error when metadata is missing", func(t *testing.T) {
+		var metadata *Metadata
+		err := metadata.Validate()
+		if err == nil {
+			t.Fatal("Expected err to be non-nil")
+		}
+		if err != ErrMissingMetadata {
+			t.Errorf("Expected '%s', got '%s'", ErrMissingMetadata.Error(), err.Error())
+		}
+	})
+
+	t.Run("return error when api version is missing", func(t *testing.T) {
+		metadata := &Metadata{}
+		err := metadata.Validate()
+		if err == nil {
+			t.Fatal("Expected err to be non-nil")
+		}
+		if err != ErrMissingAPIVersion {
+			t.Errorf("Expected '%s', got '%s'", ErrMissingAPIVersion.Error(), err.Error())
+		}
+	})
+
+	t.Run("return error when name is missing", func(t *testing.T) {
+		metadata := &Metadata{
+			APIVersion: APIVersionV1,
+		}
+		err := metadata.Validate()
+		if err == nil {
+			t.Fatal("Expected err to be non-nil")
+		}
+		if err != ErrMissingName {
+			t.Errorf("Expected %s, got '%s'", ErrMissingName, err.Error())
+		}
+	})
+
+	t.Run("return error when version is missing", func(t *testing.T) {
+		metadata := &Metadata{
+			APIVersion: APIVersionV1,
+			Name:       "testChart",
+		}
+		err := metadata.Validate()
+		if err == nil {
+			t.Fatal("Expected err to be non-nil")
+		}
+		if err != ErrMissingVersion {
+			t.Errorf("Expected %s, got '%s'", ErrMissingVersion, err.Error())
+		}
+	})
+
+	t.Run("return error when type is invalid", func(t *testing.T) {
+		metadata := &Metadata{
+			APIVersion: APIVersionV1,
+			Name:       "testChart",
+			Version:    "0.1.0",
+			Type:       "dummy",
+		}
+		err := metadata.Validate()
+		if err == nil {
+			t.Fatal("Expected err to be non-nil")
+		}
+		if err != ErrInvalidType {
+			t.Errorf("Expected '%s', got '%s'", ErrInvalidType.Error(), err.Error())
+		}
+	})
+}