fix: allow upgrading when history has nothing but failures

Signed-off-by: Matt Butcher <matt.butcher@microsoft.com>

pkg/action/upgrade.go

@@ -33,6 +33,7 @@ import (
 	"helm.sh/helm/v3/pkg/postrender"
 	"helm.sh/helm/v3/pkg/release"
 	"helm.sh/helm/v3/pkg/releaseutil"
+	"helm.sh/helm/v3/pkg/storage"
 )
 
 // Upgrade is the action for upgrading releases.
@@ -132,8 +133,24 @@ func (u *Upgrade) prepareUpgrade(name string, chart *chart.Chart, vals map[strin
 	// finds the deployed release with the given name
 	currentRelease, err := u.cfg.Releases.Deployed(name)
 	if err != nil {
+		switch err.(type) {
+		case storage.NoDeployedReleases:
+			// Try lookup again. Note that what we are doing here is attempting to get the
+			// _last release_, which might have been a failure. Our assumption is that this
+			// release best represents the current state of a rendered Helm chart. We are then
+			// relying upon the 3-way diff to help us repair the current in-cluster version.
+			u.cfg.Log("Could not find a deployed release for %q. Trying to get an older (possibly failed) release", name)
+			currentRelease, err = u.cfg.Releases.Last(name)
+			if err != nil {
+				// Regardless of what the error is here, it is likely that we cannot proceed
+				// any more with the upgrade. So we bail.
+				return nil, nil, errors.Wrapf(err, "there are no recorded releases for %q", name)
+			}
+			u.cfg.Log("loaded release %s.%d", currentRelease.Name, currentRelease.Version)
+		default:
 			return nil, nil, err
 		}
+	}
 
 	// determine if values will be reused
 	vals, err = u.reuseValues(chart, currentRelease, vals)
@@ -196,6 +213,7 @@ func (u *Upgrade) prepareUpgrade(name string, chart *chart.Chart, vals map[strin
 	if len(notesTxt) > 0 {
 		upgradedRelease.Info.Notes = notesTxt
 	}
+	u.cfg.Log("Manifest: %s", manifestDoc)
 	err = validateManifest(u.cfg.KubeClient, manifestDoc.Bytes(), !u.DisableOpenAPIValidation)
 	return currentRelease, upgradedRelease, err
 }

pkg/storage/storage.go

@@ -107,6 +107,14 @@ func (s *Storage) ListDeployed() ([]*rspb.Release, error) {
 	})
 }
 
+// NoDeployedReleases describes the situation where none of the releases in the history are deployed.
+//
+// Aggressive pruning can mask the fact that there is a deployed release, but that it
+// was cleaned up by the history pruner.
+type NoDeployedReleases string
+
+func (e NoDeployedReleases) Error() string { return string(e) }
+
 // Deployed returns the last deployed release with the provided release name, or
 // returns ErrReleaseNotFound if not found.
 func (s *Storage) Deployed(name string) (*rspb.Release, error) {
@@ -116,7 +124,7 @@ func (s *Storage) Deployed(name string) (*rspb.Release, error) {
 	}
 
 	if len(ls) == 0 {
-		return nil, errors.Errorf("%q has no deployed releases", name)
+		return nil, NoDeployedReleases(fmt.Sprintf("%q has no deployed releases", name))
 	}
 
 	// If executed concurrently, Helm's database gets corrupted
@@ -140,7 +148,7 @@ func (s *Storage) DeployedAll(name string) ([]*rspb.Release, error) {
 		return ls, nil
 	}
 	if strings.Contains(err.Error(), "not found") {
-		return nil, errors.Errorf("%q has no deployed releases", name)
+		return nil, NoDeployedReleases(fmt.Sprintf("%q has no deployed releases", name))
 	}
 	return nil, err
 }