Check against Helm v2 hash

Handle scenario where dependency hash was generated by Helm v2
but need to do a dependency build with Helm v3.

Signed-off-by: Martin Hickey <martin.hickey@ie.ibm.com>

internal/resolver/resolver.go

@@ -157,6 +157,22 @@ func HashReq(req, lock []*chart.Dependency) (string, error) {
 	return "sha256:" + s, err
 }
 
+// HashV2Req generates a hash of requirements generated in Helm v2.
+//
+// This should be used only to compare against another hash generated by the
+// Helm v2 hash function. It is to handle issue:
+// https://github.com/helm/helm/issues/7233
+func HashV2Req(req []*chart.Dependency) (string, error) {
+	dep := make(map[string][]*chart.Dependency)
+	dep["dependencies"] = req
+	data, err := json.Marshal(dep)
+	if err != nil {
+		return "", err
+	}
+	s, err := provenance.Digest(bytes.NewBuffer(data))
+	return "sha256:" + s, err
+}
+
 // GetLocalPath generates absolute local path when use
 // "file://" in repository of dependencies
 func GetLocalPath(repo, chartpath string) (string, error) {

pkg/downloader/manager.go

@@ -19,6 +19,7 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
+	"log"
 	"net/url"
 	"os"
 	"path"
@@ -87,12 +88,17 @@ func (m *Manager) Build() error {
 
 	if sum, err := resolver.HashReq(req, lock.Dependencies); err != nil || sum != lock.Digest {
 		// If lock digest differs and chart is apiVersion v1, it maybe because the lock was built
-		// with Helm 2 and should therefore be regenerated
+		// with Helm 2 and therefore should be checked with Helm v2 hash
+		// Fix for: https://github.com/helm/helm/issues/7233
 		if c.Metadata.APIVersion == chart.APIVersionV1 {
-			return m.Update()
+			log.Println("warning: a valid Helm v3 hash was not found. Checking against Helm v2 hash...")
+			if sum, err := resolver.HashV2Req(req); err != nil || sum != lock.Digest {
+				return errors.New("Chart.lock is out of sync with Chart.yaml")
 			}
+		} else {
 			return errors.New("Chart.lock is out of sync with Chart.yaml")
 		}
+	}
 
 	// Check that all of the repos we're dependent on actually exist.
 	if err := m.hasAllRepos(lock.Dependencies); err != nil {