feat: support HELMFILE_* env vars for more global flags (#2606)

* feat: support more HELMFILE_* env vars as flag fallbacks

Adds env-var fallbacks for global flags, mirroring the existing
HELMFILE_ENVIRONMENT / HELMFILE_KUBE_CONTEXT pattern:

* --helm-binary       -> HELMFILE_HELM_BINARY
* --kustomize-binary  -> HELMFILE_KUSTOMIZE_BINARY
* --log-level         -> HELMFILE_LOG_LEVEL
* --debug             -> HELMFILE_DEBUG       (expecting "true" lower case)
* --quiet             -> HELMFILE_QUIET       (expecting "true" lower case)
* --no-color          -> HELMFILE_NO_COLOR    (expecting "true" lower case),
                         additionally honors NO_COLOR per no-color.org
                         (any non-empty value disables color)

Flag values still take precedence; env vars are consulted only when the
flag is unset. The string-flag default values ("helm", "kustomize",
"info") move into the accessor methods so the env-var fallback can
actually trigger when no flag is passed.

Signed-off-by: Dominik Schmidt <dev@dominik-schmidt.de>

* docs: mention new HELMFILE_* env vars in cli.md and templating.md

Signed-off-by: Dominik Schmidt <dev@dominik-schmidt.de>

* fix: make Color/NoColor/env interaction consistent

Two issues with the env-aware NoColor() introduced together with
HELMFILE_NO_COLOR / NO_COLOR support:

1. Color() consulted the raw GlobalOptions.NoColor field instead of
   NoColor(), so in a TTY with only the env set, Color() fell through
   to terminal autodetect and ValidateConfig() spuriously errored with
   "--color and --no-color cannot be specified at the same time".

2. NoColor() returned true via env even when --color was explicitly
   passed, so `helmfile --color` with NO_COLOR (or HELMFILE_NO_COLOR=true)
   in the environment hit the same ValidateConfig() error. A flag should
   always win over an env var.

Fix both by routing Color() through NoColor() and giving NoColor() an
explicit --color short-circuit. Regression tests added for both paths.

Signed-off-by: Dominik Schmidt <dev@dominik-schmidt.de>

---------

Signed-off-by: Dominik Schmidt <dev@dominik-schmidt.de>

cmd/root.go

@@ -48,6 +48,8 @@ func toCLIError(g *config.GlobalImpl, err error) error {
 
 // NewRootCmd creates the root command for the CLI.
 func NewRootCmd(globalConfig *config.GlobalOptions) (*cobra.Command, error) {
+	globalImpl := config.NewGlobalImpl(globalConfig)
+
 	cmd := &cobra.Command{
 		Use:           "helmfile",
 		Short:         globalUsage,
@@ -58,11 +60,11 @@ func NewRootCmd(globalConfig *config.GlobalOptions) (*cobra.Command, error) {
 		PersistentPreRunE: func(c *cobra.Command, args []string) error {
 			// Valid levels:
 			// https://github.com/uber-go/zap/blob/7e7e266a8dbce911a49554b945538c5b950196b8/zapcore/level.go#L126
-			logLevel := globalConfig.LogLevel
+			logLevel := globalImpl.LogLevel()
 			switch {
-			case globalConfig.Debug:
+			case globalImpl.Debug():
 				logLevel = "debug"
-			case globalConfig.Quiet:
+			case globalImpl.Quiet():
 				logLevel = "warn"
 			}
 
@@ -83,8 +85,6 @@ func NewRootCmd(globalConfig *config.GlobalOptions) (*cobra.Command, error) {
 
 	flags.ParseErrorsAllowlist.UnknownFlags = true
 
-	globalImpl := config.NewGlobalImpl(globalConfig)
-
 	// when set environment HELMFILE_UPGRADE_NOTICE_DISABLED any value, skip upgrade notice.
 	var versionOpts []extension.CobraOption
 	if os.Getenv(envvar.UpgradeNoticeDisabled) == "" {
@@ -121,8 +121,8 @@ func NewRootCmd(globalConfig *config.GlobalOptions) (*cobra.Command, error) {
 }
 
 func setGlobalOptionsForRootCmd(fs *pflag.FlagSet, globalOptions *config.GlobalOptions) {
-	fs.StringVarP(&globalOptions.HelmBinary, "helm-binary", "b", app.DefaultHelmBinary, "Path to the helm binary")
-	fs.StringVarP(&globalOptions.KustomizeBinary, "kustomize-binary", "k", app.DefaultKustomizeBinary, "Path to the kustomize binary")
+	fs.StringVarP(&globalOptions.HelmBinary, "helm-binary", "b", "", fmt.Sprintf(`Path to the helm binary. Overrides "HELMFILE_HELM_BINARY" OS environment variable when specified (default %q)`, app.DefaultHelmBinary))
+	fs.StringVarP(&globalOptions.KustomizeBinary, "kustomize-binary", "k", "", fmt.Sprintf(`Path to the kustomize binary. Overrides "HELMFILE_KUSTOMIZE_BINARY" OS environment variable when specified (default %q)`, app.DefaultKustomizeBinary))
 	fs.StringVarP(&globalOptions.File, "file", "f", "", "load config from file or directory. defaults to \"`helmfile.yaml`\" or \"helmfile.yaml.gotmpl\" or \"helmfile.d\" (means \"helmfile.d/*.yaml\" or \"helmfile.d/*.yaml.gotmpl\") in this preference. Specify - to load the config from the standard input.")
 	fs.StringVarP(&globalOptions.Environment, "environment", "e", "", `specify the environment name. Overrides "HELMFILE_ENVIRONMENT" OS environment variable when specified. defaults to "default"`)
 	fs.StringArrayVar(&globalOptions.StateValuesSet, "state-values-set", nil, "set state values on the command line (can specify multiple or separate values with commas: key1=val1,key2=val2). Used to override .Values within the helmfile template (not values template).")
@@ -134,13 +134,13 @@ func setGlobalOptionsForRootCmd(fs *pflag.FlagSet, globalOptions *config.GlobalO
 	fs.BoolVar(&globalOptions.DisableForceUpdate, "disable-force-update", false, `do not force helm repos to update when executing "helm repo add" (Helm 3 only)`)
 	fs.BoolVar(&globalOptions.EnforcePluginVerification, "enforce-plugin-verification", false, `fail plugin installation if verification is not supported (for security purposes)`)
 	fs.BoolVar(&globalOptions.HelmOCIPlainHTTP, "oci-plain-http", false, `use plain HTTP for OCI registries (required for local/insecure registries in Helm 4)`)
-	fs.BoolVarP(&globalOptions.Quiet, "quiet", "q", false, "Silence output. Equivalent to log-level warn")
+	fs.BoolVarP(&globalOptions.Quiet, "quiet", "q", false, `Silence output. Equivalent to log-level warn. Overrides "HELMFILE_QUIET" OS environment variable when specified`)
 	fs.StringVar(&globalOptions.Kubeconfig, "kubeconfig", "", "Use a particular kubeconfig file")
 	fs.StringVar(&globalOptions.KubeContext, "kube-context", "", `Set kubectl context. Overrides "HELMFILE_KUBE_CONTEXT" OS environment variable when specified. Uses current kubectl context by default`)
-	fs.BoolVar(&globalOptions.Debug, "debug", false, "Enable verbose output for Helm and set log-level to debug, this disables --quiet/-q effect")
+	fs.BoolVar(&globalOptions.Debug, "debug", false, `Enable verbose output for Helm and set log-level to debug, this disables --quiet/-q effect. Overrides "HELMFILE_DEBUG" OS environment variable when specified`)
 	fs.BoolVar(&globalOptions.Color, "color", false, "Output with color")
-	fs.BoolVar(&globalOptions.NoColor, "no-color", false, "Output without color")
-	fs.StringVar(&globalOptions.LogLevel, "log-level", "info", "Set log level, default info")
+	fs.BoolVar(&globalOptions.NoColor, "no-color", false, `Output without color. Overrides "HELMFILE_NO_COLOR" and "NO_COLOR" OS environment variables when specified`)
+	fs.StringVar(&globalOptions.LogLevel, "log-level", "", `Set log level. Overrides "HELMFILE_LOG_LEVEL" OS environment variable when specified (default "info")`)
 	fs.StringVarP(&globalOptions.Namespace, "namespace", "n", "", `Set namespace. Overrides "HELMFILE_NAMESPACE" OS environment variable when specified. Uses the namespace set in the context by default, and is available in templates as {{ .Namespace }}`)
 	fs.StringVarP(&globalOptions.Chart, "chart", "c", "", "Set chart. Uses the chart set in release by default, and is available in template as {{ .Chart }}")
 	fs.StringArrayVarP(&globalOptions.Selector, "selector", "l", nil, `Only run using the releases that match labels. Labels can take the form of foo=bar or foo!=bar.

docs/cli.md

@@ -40,21 +40,21 @@ Flags:
       --allow-no-matching-release             Do not exit with an error code if the provided selector has no matching releases.
   -c, --chart string                          Set chart. Uses the chart set in release by default, and is available in template as {{ .Chart }}
       --color                                 Output with color
-      --debug                                 Enable verbose output for Helm and set log-level to debug, this disables --quiet/-q effect
+      --debug                                 Enable verbose output for Helm and set log-level to debug, this disables --quiet/-q effect. Overrides "HELMFILE_DEBUG" OS environment variable when specified
       --disable-force-update                  do not force helm repos to update when executing "helm repo add"
       --enable-live-output                    Show live output from the Helm binary Stdout/Stderr into Helmfile own Stdout/Stderr.
                                               It only applies for the Helm CLI commands, Stdout/Stderr for Hooks are still displayed only when it's execution finishes.
   -e, --environment string                    specify the environment name. Overrides "HELMFILE_ENVIRONMENT" OS environment variable when specified. defaults to "default"
   -f, --file helmfile.yaml                    load config from file or directory. defaults to "helmfile.yaml" or "helmfile.yaml.gotmpl" or "helmfile.d" (means "helmfile.d/*.yaml" or "helmfile.d/*.yaml.gotmpl") in this preference. Specify - to load the config from the standard input.
-  -b, --helm-binary string                    Path to the helm binary (default "helm")
+  -b, --helm-binary string                    Path to the helm binary. Overrides "HELMFILE_HELM_BINARY" OS environment variable when specified (default "helm")
   -h, --help                                  help for helmfile
   -i, --interactive                           Request confirmation before attempting to modify clusters
       --kube-context string                   Set kubectl context. Overrides "HELMFILE_KUBE_CONTEXT" OS environment variable when specified. Uses current kubectl context by default
-  -k, --kustomize-binary string               Path to the kustomize binary (default "kustomize")
-      --log-level string                      Set log level, default info (default "info")
+  -k, --kustomize-binary string               Path to the kustomize binary. Overrides "HELMFILE_KUSTOMIZE_BINARY" OS environment variable when specified (default "kustomize")
+      --log-level string                      Set log level. Overrides "HELMFILE_LOG_LEVEL" OS environment variable when specified (default "info")
   -n, --namespace string                      Set namespace. Overrides "HELMFILE_NAMESPACE" OS environment variable when specified. Uses the namespace set in the context by default, and is available in templates as {{ .Namespace }}
-      --no-color                              Output without color
-  -q, --quiet                                 Silence output. Equivalent to log-level warn
+      --no-color                              Output without color. Overrides "HELMFILE_NO_COLOR" and "NO_COLOR" OS environment variables when specified
+  -q, --quiet                                 Silence output. Equivalent to log-level warn. Overrides "HELMFILE_QUIET" OS environment variable when specified
   -l, --selector stringArray                  Only run using the releases that match labels. Labels can take the form of foo=bar or foo!=bar.
                                               A release must match all labels in a group in order to be used. Multiple groups can be specified at once.
                                               "--selector tier=frontend,tier!=proxy --selector tier=backend" will match all frontend, non-proxy releases AND all backend releases.

docs/templating.md

@@ -68,6 +68,12 @@ Helmfile uses some OS environment variables to override default behaviour:
 * `HELMFILE_ENVIRONMENT` - specify [Helmfile environment](environments.md), it has lower priority than CLI argument `--environment`
 * `HELMFILE_KUBE_CONTEXT` - specify the kubectl context, it has lower priority than CLI argument `--kube-context`
 * `HELMFILE_NAMESPACE` - specify the namespace, it has lower priority than CLI argument `--namespace`
+* `HELMFILE_HELM_BINARY` - specify the path to the helm binary, it has lower priority than CLI argument `--helm-binary`
+* `HELMFILE_KUSTOMIZE_BINARY` - specify the path to the kustomize binary, it has lower priority than CLI argument `--kustomize-binary`
+* `HELMFILE_LOG_LEVEL` - specify the log level, it has lower priority than CLI argument `--log-level`
+* `HELMFILE_DEBUG` - enable debug output, expecting `true` lower case. The same as `--debug` CLI flag
+* `HELMFILE_QUIET` - silence output (equivalent to log-level warn), expecting `true` lower case. The same as `--quiet`/`-q` CLI flag
+* `HELMFILE_NO_COLOR` - disable colored output, expecting `true` lower case. The same as `--no-color` CLI flag. `NO_COLOR` (any non-empty value, per [no-color.org](https://no-color.org/)) is also honored
 * `HELMFILE_TEMPDIR` - specify directory to store temporary files
 * `HELMFILE_UPGRADE_NOTICE_DISABLED` - expecting any non-empty value to skip the check for the latest version of Helmfile in [helmfile version](cli.md#version)
 * `HELMFILE_GO_YAML_V3` - use *go.yaml.in/yaml/v3* instead of *go.yaml.in/yaml/v2*.  It's `false` by default in Helmfile v0.x, and `true` in Helmfile v1.x.

pkg/config/global.go

@@ -109,12 +109,63 @@ func (g *GlobalImpl) SetSet(set map[string]any) {
 
 // HelmBinary returns the path to the Helm binary.
 func (g *GlobalImpl) HelmBinary() string {
-	return g.GlobalOptions.HelmBinary
+	var helmBinary string
+
+	switch {
+	case g.GlobalOptions.HelmBinary != "":
+		helmBinary = g.GlobalOptions.HelmBinary
+	case os.Getenv("HELMFILE_HELM_BINARY") != "":
+		helmBinary = os.Getenv("HELMFILE_HELM_BINARY")
+	default:
+		helmBinary = state.DefaultHelmBinary
+	}
+	return helmBinary
 }
 
 // KustomizeBinary returns the path to the Kustomize binary.
 func (g *GlobalImpl) KustomizeBinary() string {
-	return g.GlobalOptions.KustomizeBinary
+	var kustomizeBinary string
+
+	switch {
+	case g.GlobalOptions.KustomizeBinary != "":
+		kustomizeBinary = g.GlobalOptions.KustomizeBinary
+	case os.Getenv("HELMFILE_KUSTOMIZE_BINARY") != "":
+		kustomizeBinary = os.Getenv("HELMFILE_KUSTOMIZE_BINARY")
+	default:
+		kustomizeBinary = state.DefaultKustomizeBinary
+	}
+	return kustomizeBinary
+}
+
+// LogLevel returns the log level to use.
+func (g *GlobalImpl) LogLevel() string {
+	var logLevel string
+
+	switch {
+	case g.GlobalOptions.LogLevel != "":
+		logLevel = g.GlobalOptions.LogLevel
+	case os.Getenv("HELMFILE_LOG_LEVEL") != "":
+		logLevel = os.Getenv("HELMFILE_LOG_LEVEL")
+	default:
+		logLevel = "info"
+	}
+	return logLevel
+}
+
+// Debug returns whether debug output is enabled.
+func (g *GlobalImpl) Debug() bool {
+	if g.GlobalOptions.Debug {
+		return true
+	}
+	return os.Getenv(envvar.Debug) == "true"
+}
+
+// Quiet returns whether quiet output is enabled.
+func (g *GlobalImpl) Quiet() bool {
+	if g.GlobalOptions.Quiet {
+		return true
+	}
+	return os.Getenv(envvar.Quiet) == "true"
 }
 
 // Kubeconfig returns the path to the kubeconfig file to use.
@@ -242,7 +293,7 @@ func (g *GlobalImpl) Color() bool {
 		return c
 	}
 
-	if g.GlobalOptions.NoColor {
+	if g.NoColor() {
 		return false
 	}
 
@@ -259,7 +310,18 @@ func (g *GlobalImpl) Color() bool {
 
 // NoColor returns the no color flag
 func (g *GlobalImpl) NoColor() bool {
-	return g.GlobalOptions.NoColor
+	if g.GlobalOptions.NoColor {
+		return true
+	}
+	// Explicit --color short-circuits env-derived no-color: a flag must win over an env var.
+	if g.GlobalOptions.Color {
+		return false
+	}
+	if os.Getenv(envvar.NoColor) == "true" {
+		return true
+	}
+	// Honor the de-facto https://no-color.org/ standard: any non-empty value disables color.
+	return os.Getenv("NO_COLOR") != ""
 }
 
 // Env returns the environment to use.
@@ -296,7 +358,7 @@ func (g *GlobalImpl) Interactive() bool {
 // Args returns the args to use for helm
 func (g *GlobalImpl) Args() string {
 	args := g.GlobalOptions.Args
-	enableHelmDebug := g.Debug
+	enableHelmDebug := g.Debug()
 
 	if enableHelmDebug {
 		args = fmt.Sprintf("%s %s", args, "--debug")

pkg/config/global_test.go

@@ -119,3 +119,304 @@ func TestNamespace(t *testing.T) {
 	}
 	os.Unsetenv(envvar.Namespace)
 }
+
+// TestHelmBinary tests the helm-binary flag and HELMFILE_HELM_BINARY env var fallback
+func TestHelmBinary(t *testing.T) {
+	tests := []struct {
+		opts     GlobalOptions
+		env      string
+		expected string
+	}{
+		{
+			opts:     GlobalOptions{},
+			env:      "",
+			expected: "helm",
+		},
+		{
+			opts:     GlobalOptions{},
+			env:      "envset",
+			expected: "envset",
+		},
+		{
+			opts:     GlobalOptions{HelmBinary: "flagset"},
+			env:      "",
+			expected: "flagset",
+		},
+		{
+			opts:     GlobalOptions{HelmBinary: "flagset"},
+			env:      "envset",
+			expected: "flagset",
+		},
+	}
+
+	for _, test := range tests {
+		os.Setenv(envvar.HelmBinary, test.env)
+		received := NewGlobalImpl(&test.opts).HelmBinary()
+		require.Equalf(t, test.expected, received, "HelmBinary expected %s, received %s", test.expected, received)
+	}
+	os.Unsetenv(envvar.HelmBinary)
+}
+
+// TestKustomizeBinary tests the kustomize-binary flag and HELMFILE_KUSTOMIZE_BINARY env var fallback
+func TestKustomizeBinary(t *testing.T) {
+	tests := []struct {
+		opts     GlobalOptions
+		env      string
+		expected string
+	}{
+		{
+			opts:     GlobalOptions{},
+			env:      "",
+			expected: "kustomize",
+		},
+		{
+			opts:     GlobalOptions{},
+			env:      "envset",
+			expected: "envset",
+		},
+		{
+			opts:     GlobalOptions{KustomizeBinary: "flagset"},
+			env:      "",
+			expected: "flagset",
+		},
+		{
+			opts:     GlobalOptions{KustomizeBinary: "flagset"},
+			env:      "envset",
+			expected: "flagset",
+		},
+	}
+
+	for _, test := range tests {
+		os.Setenv(envvar.KustomizeBinary, test.env)
+		received := NewGlobalImpl(&test.opts).KustomizeBinary()
+		require.Equalf(t, test.expected, received, "KustomizeBinary expected %s, received %s", test.expected, received)
+	}
+	os.Unsetenv(envvar.KustomizeBinary)
+}
+
+// TestLogLevel tests the log-level flag and HELMFILE_LOG_LEVEL env var fallback
+func TestLogLevel(t *testing.T) {
+	tests := []struct {
+		opts     GlobalOptions
+		env      string
+		expected string
+	}{
+		{
+			opts:     GlobalOptions{},
+			env:      "",
+			expected: "info",
+		},
+		{
+			opts:     GlobalOptions{},
+			env:      "envset",
+			expected: "envset",
+		},
+		{
+			opts:     GlobalOptions{LogLevel: "flagset"},
+			env:      "",
+			expected: "flagset",
+		},
+		{
+			opts:     GlobalOptions{LogLevel: "flagset"},
+			env:      "envset",
+			expected: "flagset",
+		},
+	}
+
+	for _, test := range tests {
+		os.Setenv(envvar.LogLevel, test.env)
+		received := NewGlobalImpl(&test.opts).LogLevel()
+		require.Equalf(t, test.expected, received, "LogLevel expected %s, received %s", test.expected, received)
+	}
+	os.Unsetenv(envvar.LogLevel)
+}
+
+// TestDebug tests the debug flag and HELMFILE_DEBUG env var fallback
+func TestDebug(t *testing.T) {
+	tests := []struct {
+		opts     GlobalOptions
+		env      string
+		expected bool
+	}{
+		{
+			opts:     GlobalOptions{},
+			env:      "",
+			expected: false,
+		},
+		{
+			opts:     GlobalOptions{},
+			env:      "true",
+			expected: true,
+		},
+		{
+			opts:     GlobalOptions{},
+			env:      "anything",
+			expected: false,
+		},
+		{
+			opts:     GlobalOptions{Debug: true},
+			env:      "",
+			expected: true,
+		},
+		{
+			opts:     GlobalOptions{Debug: true},
+			env:      "true",
+			expected: true,
+		},
+	}
+
+	for _, test := range tests {
+		os.Setenv(envvar.Debug, test.env)
+		received := NewGlobalImpl(&test.opts).Debug()
+		require.Equalf(t, test.expected, received, "Debug expected %t, received %t", test.expected, received)
+	}
+	os.Unsetenv(envvar.Debug)
+}
+
+// TestQuiet tests the quiet flag and HELMFILE_QUIET env var fallback
+func TestQuiet(t *testing.T) {
+	tests := []struct {
+		opts     GlobalOptions
+		env      string
+		expected bool
+	}{
+		{
+			opts:     GlobalOptions{},
+			env:      "",
+			expected: false,
+		},
+		{
+			opts:     GlobalOptions{},
+			env:      "true",
+			expected: true,
+		},
+		{
+			opts:     GlobalOptions{},
+			env:      "anything",
+			expected: false,
+		},
+		{
+			opts:     GlobalOptions{Quiet: true},
+			env:      "",
+			expected: true,
+		},
+		{
+			opts:     GlobalOptions{Quiet: true},
+			env:      "true",
+			expected: true,
+		},
+	}
+
+	for _, test := range tests {
+		os.Setenv(envvar.Quiet, test.env)
+		received := NewGlobalImpl(&test.opts).Quiet()
+		require.Equalf(t, test.expected, received, "Quiet expected %t, received %t", test.expected, received)
+	}
+	os.Unsetenv(envvar.Quiet)
+}
+
+// TestNoColor tests the no-color flag, HELMFILE_NO_COLOR and NO_COLOR env var fallbacks
+func TestNoColor(t *testing.T) {
+	tests := []struct {
+		opts        GlobalOptions
+		helmfileEnv string
+		standardEnv string
+		expected    bool
+	}{
+		{
+			opts:        GlobalOptions{},
+			helmfileEnv: "",
+			standardEnv: "",
+			expected:    false,
+		},
+		{
+			opts:        GlobalOptions{},
+			helmfileEnv: "true",
+			standardEnv: "",
+			expected:    true,
+		},
+		{
+			opts:        GlobalOptions{},
+			helmfileEnv: "anything",
+			standardEnv: "",
+			expected:    false,
+		},
+		{
+			opts:        GlobalOptions{},
+			helmfileEnv: "",
+			standardEnv: "1",
+			expected:    true,
+		},
+		{
+			opts:        GlobalOptions{},
+			helmfileEnv: "",
+			standardEnv: "anything",
+			expected:    true,
+		},
+		{
+			opts:        GlobalOptions{NoColor: true},
+			helmfileEnv: "",
+			standardEnv: "",
+			expected:    true,
+		},
+	}
+
+	for _, test := range tests {
+		os.Setenv(envvar.NoColor, test.helmfileEnv)
+		os.Setenv("NO_COLOR", test.standardEnv)
+		received := NewGlobalImpl(&test.opts).NoColor()
+		require.Equalf(t, test.expected, received, "NoColor expected %t, received %t", test.expected, received)
+	}
+	os.Unsetenv(envvar.NoColor)
+	os.Unsetenv("NO_COLOR")
+}
+
+// TestColorRespectsNoColorEnv guards against ValidateConfig() firing when
+// HELMFILE_NO_COLOR / NO_COLOR is set without an explicit --color/--no-color flag.
+// Color() must consult NoColor() (which is env-aware) before falling back to TTY autodetect.
+func TestColorRespectsNoColorEnv(t *testing.T) {
+	tests := []struct {
+		name        string
+		helmfileEnv string
+		standardEnv string
+	}{
+		{name: "HELMFILE_NO_COLOR=true", helmfileEnv: "true"},
+		{name: "NO_COLOR set", standardEnv: "1"},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			t.Setenv(envvar.NoColor, test.helmfileEnv)
+			t.Setenv("NO_COLOR", test.standardEnv)
+			g := NewGlobalImpl(&GlobalOptions{})
+			require.True(t, g.NoColor(), "NoColor() should be true when env is set")
+			require.False(t, g.Color(), "Color() should be false when NoColor() is true via env")
+			require.NoError(t, g.ValidateConfig(), "ValidateConfig() should not error from env-only no-color")
+		})
+	}
+}
+
+// TestColorFlagOverridesNoColorEnv guards against ValidateConfig() firing when
+// --color is explicitly passed but HELMFILE_NO_COLOR / NO_COLOR is set in the
+// environment. The flag must win over the env var.
+func TestColorFlagOverridesNoColorEnv(t *testing.T) {
+	tests := []struct {
+		name        string
+		helmfileEnv string
+		standardEnv string
+	}{
+		{name: "HELMFILE_NO_COLOR=true", helmfileEnv: "true"},
+		{name: "NO_COLOR set", standardEnv: "1"},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			t.Setenv(envvar.NoColor, test.helmfileEnv)
+			t.Setenv("NO_COLOR", test.standardEnv)
+			g := NewGlobalImpl(&GlobalOptions{Color: true})
+			require.True(t, g.Color(), "Color() should be true when --color is set")
+			require.False(t, g.NoColor(), "NoColor() should be false when --color is set, even if env says otherwise")
+			require.NoError(t, g.ValidateConfig(), "ValidateConfig() should not error when --color overrides env no-color")
+		})
+	}
+}

pkg/envvar/const.go

@@ -11,6 +11,12 @@ const (
 	Environment           = "HELMFILE_ENVIRONMENT"
 	KubeContext           = "HELMFILE_KUBE_CONTEXT"
 	Namespace             = "HELMFILE_NAMESPACE"
+	HelmBinary            = "HELMFILE_HELM_BINARY"
+	KustomizeBinary       = "HELMFILE_KUSTOMIZE_BINARY"
+	LogLevel              = "HELMFILE_LOG_LEVEL"
+	Debug                 = "HELMFILE_DEBUG"
+	Quiet                 = "HELMFILE_QUIET"
+	NoColor               = "HELMFILE_NO_COLOR"
 	FilePath              = "HELMFILE_FILE_PATH"
 	TempDir               = "HELMFILE_TEMPDIR"
 	UpgradeNoticeDisabled = "HELMFILE_UPGRADE_NOTICE_DISABLED"