fix: avoid importing testing package in release builds

internal/version and pkg/chart/common imported "testing" only to call
testing.Testing(), pulling the testing package and its dependencies
into release binaries.

Replace those checks with exported KubeVersionMajorTesting /
KubeVersionMinorTesting sentinels that default to zero. A new
build-tagged file internal/version/version_helmtest.go seeds them in
init() and only compiles under -tags helmtest.

The Makefile applies -tags helmtest as a baseline so test-unit and
test-coverage work directly or via `make test`. scripts/coverage.sh
passes the tag to its raw `go test` call. CONTRIBUTING.md documents
that contributors running tests outside the Makefile must pass the
tag themselves.

Signed-off-by: Evans Mungai <mbuevans@gmail.com>

CONTRIBUTING.md

@@ -232,6 +232,20 @@ guide](https://helm.sh/docs/community/developers/) to get started.
 Coding conventions and standards are explained in the [official developer
 docs](https://helm.sh/docs/developers/).
 
+### Running tests
+
+Use the Makefile targets (`make test`, `make test-unit`, `make test-coverage`)
+rather than invoking `go test ./...` directly. The Makefile passes the
+`helmtest` build tag, which is required: it activates
+`internal/version/version_helmtest.go` to seed testing-version sentinels. Test
+binaries have no module info, so without this tag the production code path
+attempts to read `k8s.io/client-go`'s version from build info and panics during
+package init.
+
+If you run tests outside the Makefile (IDE test runners, `go test` directly,
+custom CI), pass `-tags helmtest`. The tag is omitted from release builds so
+the `testing` package and its dependencies stay out of shipped binaries.
+
 ## Pull Requests
 
 Like any good open source project, we use Pull Requests (PRs) to track code changes.

Makefile

@@ -89,6 +89,11 @@ endif
 test: test-style
 test: test-unit
 
+# The `helmtest` build tag activates internal/version/version_helmtest.go,
+# which seeds testing-version sentinels so test binaries don't panic reading
+# missing module info. Applied to all test invocations.
+TESTFLAGS += -tags helmtest
+
 .PHONY: test-unit
 test-unit:
 	@echo

internal/version/version.go

@@ -17,12 +17,10 @@ limitations under the License.
 package version
 
 import (
-	"flag"
 	"fmt"
 	"log/slog"
 	"runtime"
 	"strings"
-	"testing"
 
 	"github.com/Masterminds/semver/v3"
 )
@@ -44,8 +42,9 @@ var (
 	gitTreeState = ""
 )
 
-const (
+var (
-	kubeClientGoVersionTesting = "v1.20"
+	KubeVersionMajorTesting uint64
+	KubeVersionMinorTesting uint64
 )
 
 // BuildInfo describes the compile time information.
@@ -82,8 +81,8 @@ func Get() BuildInfo {
 		// Test builds don't include debug info / module info
 		// (And even if they did, we probably want a stable version during tests anyway)
 		// Return a default value for test builds
-		if testing.Testing() {
+		if KubeVersionMajorTesting != 0 && KubeVersionMinorTesting != 0 {
-			return kubeClientGoVersionTesting
+			return fmt.Sprintf("v%d.%d", KubeVersionMajorTesting, KubeVersionMinorTesting)
 		}
 
 		vstr, err := K8sIOClientGoModVersion()
@@ -113,7 +112,7 @@ func Get() BuildInfo {
 	}
 
 	// HACK(bacongobbler): strip out GoVersion during a test run for consistent test output
-	if flag.Lookup("test.v") != nil {
+	if KubeVersionMajorTesting != 0 && KubeVersionMinorTesting != 0 {
 		v.GoVersion = ""
 	}
 	return v

internal/version/version_helmtest.go

@@ -0,0 +1,31 @@
+//go:build helmtest
+
+/*
+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 version
+
+// This file is only compiled when the `helmtest` build tag is set (applied by
+// the Makefile to all test invocations). It seeds the testing-version
+// sentinels so that production code paths in this package and in
+// pkg/chart/common substitute stable values instead of attempting to read
+// build info from a `go test` binary (which has no module info and would
+// panic during package init).
+
+func init() {
+	KubeVersionMajorTesting = 1
+	KubeVersionMinorTesting = 20
+}

pkg/chart/common/capabilities.go

@@ -20,7 +20,6 @@ import (
 	"slices"
 	"strconv"
 	"strings"
-	"testing"
 
 	"github.com/Masterminds/semver/v3"
 	"k8s.io/client-go/kubernetes/scheme"
@@ -32,11 +31,6 @@ import (
 	helmversion "helm.sh/helm/v4/internal/version"
 )
 
-const (
-	kubeVersionMajorTesting = 1
-	kubeVersionMinorTesting = 20
-)
-
 var (
 	// DefaultVersionSet is the default version set, which includes only Core V1 ("v1").
 	DefaultVersionSet = allKnownVersions()
@@ -146,8 +140,8 @@ func makeDefaultCapabilities() (*Capabilities, error) {
 	// Test builds don't include debug info / module info
 	// (And even if they did, we probably want stable capabilities for tests anyway)
 	// Return a default value for test builds
-	if testing.Testing() {
+	if helmversion.KubeVersionMajorTesting != 0 && helmversion.KubeVersionMinorTesting != 0 {
-		return newCapabilities(kubeVersionMajorTesting, kubeVersionMinorTesting)
+		return newCapabilities(helmversion.KubeVersionMajorTesting, helmversion.KubeVersionMinorTesting)
 	}
 
 	vstr, err := helmversion.K8sIOClientGoModVersion()

scripts/coverage.sh

@@ -37,7 +37,7 @@ generate_cover_data() {
   for d in $(go list "$target"); do
     (
       local output="${coverdir}/${d//\//-}.cover"
-      go test -coverprofile="${output}" -covermode="$covermode" "$d"
+      go test -tags helmtest -coverprofile="${output}" -covermode="$covermode" "$d"
     )
   done