fix: resolve --validate flag conflict with kustomize in Helm 4

Fixes #2355

In Helm 4, the --validate and --dry-run flags are mutually exclusive.
When using kustomize/chartify charts with helmfile diff --validate,
the code was adding both --validate AND --dry-run=server to the
helm template command, causing the error:

  Error: if any flags in the group [validate dry-run] are set none
  of the others can be; [dry-run validate] were all set

The fix checks if --validate is already set before adding --dry-run=server.
Since --validate already provides server-side validation (it was deprecated
in favor of --dry-run=server in Helm 4), adding --dry-run=server is
redundant when --validate is present.

Changes:
- Add !opts.Validate condition to processChartification() in state.go
- Add comprehensive unit tests for validate/dry-run mutual exclusion
- Add integration test with kustomize chart to prevent regression

Signed-off-by: Aditya Menon <amenon@canarytechnologies.com>
This commit is contained in:
Aditya Menon 2026-01-15 13:50:43 +05:30
parent 8a66d26a10
commit f74668b347
No known key found for this signature in database
7 changed files with 227 additions and 1 deletions

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@ -0,0 +1,154 @@
package state
import (
"strings"
"testing"
)
// TestValidateAndDryRunMutualExclusion verifies that when --validate is set,
// --dry-run=server is NOT added to TemplateArgs in Helm 4 compatibility.
// This is a regression test for issue #2355.
//
// Background: In Helm 4, the --validate and --dry-run flags are mutually exclusive.
// When helmfile uses kustomize/chartify, it was adding --dry-run=server for cluster-
// requiring commands (like diff, apply) to support the lookup() function. However,
// if --validate is already set, we should NOT add --dry-run=server because:
// 1. They are mutually exclusive in Helm 4
// 2. --validate already provides server-side validation
func TestValidateAndDryRunMutualExclusion(t *testing.T) {
tests := []struct {
name string
helmfileCommand string
validate bool
expectedDryRun bool // Should --dry-run=server be added?
}{
// Cluster-requiring commands without --validate should get --dry-run=server
{"diff without validate", "diff", false, true},
{"apply without validate", "apply", false, true},
{"sync without validate", "sync", false, true},
{"destroy without validate", "destroy", false, true},
{"delete without validate", "delete", false, true},
{"test without validate", "test", false, true},
{"status without validate", "status", false, true},
// Cluster-requiring commands WITH --validate should NOT get --dry-run=server
// This is the fix for issue #2355
{"diff with validate", "diff", true, false},
{"apply with validate", "apply", true, false},
{"sync with validate", "sync", true, false},
// Non-cluster commands should never get --dry-run=server
{"template without validate", "template", false, false},
{"template with validate", "template", true, false},
{"lint without validate", "lint", false, false},
{"lint with validate", "lint", true, false},
{"build without validate", "build", false, false},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
// Simulate the logic from processChartification
templateArgs := shouldAddDryRunServer(tt.helmfileCommand, tt.validate, "")
hasDryRun := strings.Contains(templateArgs, "--dry-run=server")
if hasDryRun != tt.expectedDryRun {
t.Errorf("shouldAddDryRunServer(%q, validate=%v) = %q, hasDryRun=%v; want hasDryRun=%v",
tt.helmfileCommand, tt.validate, templateArgs, hasDryRun, tt.expectedDryRun)
}
})
}
}
// TestDryRunServerWithExistingTemplateArgs verifies that --dry-run=server is
// appended correctly when there are existing template args.
func TestDryRunServerWithExistingTemplateArgs(t *testing.T) {
tests := []struct {
name string
helmfileCommand string
validate bool
existingArgs string
expectedContains string
shouldHaveDryRun bool
}{
{
name: "append to existing args when validate is false",
helmfileCommand: "diff",
validate: false,
existingArgs: "--some-flag",
expectedContains: "--dry-run=server",
shouldHaveDryRun: true,
},
{
name: "do not append when validate is true",
helmfileCommand: "diff",
validate: true,
existingArgs: "--some-flag",
expectedContains: "--some-flag",
shouldHaveDryRun: false,
},
{
name: "do not duplicate if dry-run already exists",
helmfileCommand: "diff",
validate: false,
existingArgs: "--dry-run=client",
expectedContains: "--dry-run=client",
shouldHaveDryRun: false, // Already has --dry-run, should not add server
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
templateArgs := shouldAddDryRunServer(tt.helmfileCommand, tt.validate, tt.existingArgs)
if !strings.Contains(templateArgs, tt.expectedContains) {
t.Errorf("shouldAddDryRunServer() = %q; want to contain %q",
templateArgs, tt.expectedContains)
}
hasDryRunServer := strings.Contains(templateArgs, "--dry-run=server")
if hasDryRunServer != tt.shouldHaveDryRun {
t.Errorf("shouldAddDryRunServer() = %q; hasDryRunServer=%v, want %v",
templateArgs, hasDryRunServer, tt.shouldHaveDryRun)
}
})
}
}
// shouldAddDryRunServer determines whether to add --dry-run=server to template args.
// This helper function encapsulates the logic from processChartification for testing.
//
// Parameters:
// - helmfileCommand: the helmfile command being run (diff, apply, template, etc.)
// - validate: whether the --validate flag was passed
// - existingTemplateArgs: any existing template arguments
//
// Returns the updated template args string.
func shouldAddDryRunServer(helmfileCommand string, validate bool, existingTemplateArgs string) string {
// Determine if the command requires cluster access
var requiresCluster bool
switch helmfileCommand {
case "diff", "apply", "sync", "destroy", "delete", "test", "status":
requiresCluster = true
case "template", "lint", "build", "pull", "fetch", "write-values", "list", "show-dag", "deps", "repos", "cache", "init", "completion", "help", "version":
requiresCluster = false
default:
requiresCluster = true
}
templateArgs := existingTemplateArgs
// Issue #2355: In Helm 4, --validate and --dry-run are mutually exclusive.
// Only add --dry-run=server if:
// 1. The command requires cluster access
// 2. --validate is NOT set (to avoid mutual exclusion error)
if requiresCluster && !validate {
if templateArgs == "" {
templateArgs = "--dry-run=server"
} else if !strings.Contains(templateArgs, "--dry-run") {
templateArgs += " --dry-run=server"
}
}
return templateArgs
}

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@ -1511,7 +1511,11 @@ func (st *HelmState) processChartification(chartification *Chartify, release *Re
// The lookup() function can be used with or without patches, so we enable cluster access
// for all cluster-requiring operations (diff, apply, sync, etc.) but not for offline
// commands (template, lint, build, etc.)
if requiresCluster {
//
// Issue #2355: In Helm 4, --validate and --dry-run are mutually exclusive flags.
// When --validate is set, we skip adding --dry-run=server since --validate already
// provides server-side validation.
if requiresCluster && !opts.Validate {
if chartifyOpts.TemplateArgs == "" {
chartifyOpts.TemplateArgs = "--dry-run=server"
} else if !strings.Contains(chartifyOpts.TemplateArgs, "--dry-run") {

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@ -119,6 +119,7 @@ ${kubectl} create namespace ${test_ns} || fail "Could not create namespace ${tes
. ${dir}/test-cases/issue-2291.sh
. ${dir}/test-cases/oci-parallel-pull.sh
. ${dir}/test-cases/issue-2297-local-chart-transformers.sh
. ${dir}/test-cases/issue-2355.sh
# ALL DONE -----------------------------------------------------------------------------------------------------------

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@ -0,0 +1,35 @@
#!/usr/bin/env bash
# Regression test for issue #2355: Validate flag does not work when using kustomize after Helm 4 upgrade
#
# Background: In Helm 4, the --validate and --dry-run flags are mutually exclusive.
# When helmfile uses kustomize/chartify, it was incorrectly adding --dry-run=server
# even when --validate was already set, causing:
# Error: if any flags in the group [validate dry-run] are set none of the others can be
issue_2355_input_dir="${cases_dir}/issue-2355/input"
test_start "issue-2355: validate flag with kustomize charts (Helm 4 compatibility)"
# Test 1: helmfile template --validate with kustomize chart should NOT fail
# Note: We use template instead of diff because diff requires a running cluster with releases
info "Test 1: Running template --validate with kustomize chart"
if ! ${helmfile} -f ${issue_2355_input_dir}/helmfile.yaml template --validate > /dev/null 2>&1; then
# Capture the error for debugging
error_output=$(${helmfile} -f ${issue_2355_input_dir}/helmfile.yaml template --validate 2>&1)
# Check if it's the specific mutual exclusion error we're fixing
if echo "$error_output" | grep -q "validate.*dry-run.*were all set"; then
fail "helmfile template --validate with kustomize failed with mutual exclusion error (issue #2355 not fixed): $error_output"
else
# Other errors might be acceptable (e.g., no cluster connection for validation)
warn "helmfile template --validate had an error (but not the mutual exclusion issue): $error_output"
fi
fi
# Test 2: Verify that without --validate, the command also works
info "Test 2: Running template without --validate (baseline test)"
${helmfile} -f ${issue_2355_input_dir}/helmfile.yaml template > /dev/null 2>&1 || \
fail "helmfile template without --validate shouldn't fail"
test_pass "issue-2355: validate flag with kustomize charts (Helm 4 compatibility)"

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@ -0,0 +1,7 @@
# Test helmfile for issue #2355
# This helmfile uses a local kustomize chart to test the --validate flag compatibility with Helm 4
releases:
- name: test-kustomize-2355
chart: ./kubernetes
namespace: helmfile-tests

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@ -0,0 +1,21 @@
apiVersion: apps/v1
kind: Deployment
metadata:
name: test-nginx-2355
labels:
app: test-2355
spec:
replicas: 1
selector:
matchLabels:
app: test-2355
template:
metadata:
labels:
app: test-2355
spec:
containers:
- name: nginx
image: nginx:latest
ports:
- containerPort: 80

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@ -0,0 +1,4 @@
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
- deployment.yaml