nil pointer dereference to Manager.out when performing dependency update

[KKatev-reasonance]

Problem

I am trying to deploy a chart with external dependencies defined in its chart.yaml. When setting DependencyUpdate: true in the chart spec, the following nil pointer error occurs:

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0xdb8f74]

goroutine 111 [running]:
fmt.Fprintln({0x0, 0x0}, {0xc009729ad8, 0x1, 0x1})
        /usr/local/go/src/fmt/print.go:265 +0x54
helm.sh/helm/v3/pkg/downloader.(*Manager).UpdateRepositories(0xc0037166c0)
        /go/pkg/mod/helm.sh/helm/[email protected]/pkg/downloader/manager.go:653 +0x96
helm.sh/helm/v3/pkg/downloader.(*Manager).Update(0xc0037166c0)
        /go/pkg/mod/helm.sh/helm/[email protected]/pkg/downloader/manager.go:188 +0xb4
github.com/mittwald/go-helm-client.(*HelmClient).install(0xc001ab3140, {0x28251f8, 0xc0000580a0}, 0xc002a10140)
        /go/pkg/mod/github.com/mittwald/[email protected]/client.go:293 +0x4ad
github.com/mittwald/go-helm-client.(*HelmClient).InstallOrUpgradeChart(0x259e5e3, {0x28251f8, 0xc0000580a0}, 0xc001a925d0)
        /go/pkg/mod/github.com/mittwald/[email protected]/client.go:206 +0x7a

Context

go.mod requirements:

require (
	github.com/mittwald/go-helm-client v0.9.0
	gopkg.in/yaml.v2 v2.4.0
	helm.sh/helm/v3 v3.8.0
	k8s.io/client-go v0.23.1
)

The deployed chart is the official gitea helm chart, which has several references to the bitnami repository.

Cause and a quick fix

The cause of this error seems to be the initialzation of downloader.Manager in client.go:285, where Out is not set. Manager.Out is used in the standard Helm package for writing simple output when checking for dependencies. I circumvented the issue by declaring a bytes.Buffer variable and setting Manager.Out to it, though I suspect one would want an implementation-specific io.writer in that case.