feat: add Helm 4 post-renderer plugin and enable Helm 4 issue-2515 integration test

Agent-Logs-Url: https://github.com/helmfile/helmfile/sessions/3da2949c-a9d6-4e16-9b4a-a7e241080089

Co-authored-by: yxxhero <11087727+yxxhero@users.noreply.github.com>

test/integration/test-cases/issue-2515.sh

@@ -1,39 +1,49 @@
 issue_2515_case_dir="$(cd "${cases_dir}/issue-2515" && pwd)"
 issue_2515_tmp=$(mktemp -d)
 
+# Determine the post-renderer argument.
+# Helm 3 accepts an executable script; Helm 4 requires a plugin name.
 if [ "${HELMFILE_HELM4}" = "1" ]; then
-    info "Skipping issue-2515 test for Helm 4 (Helm 4 natively applies --post-renderer to --output-dir output)"
-    test_start "issue-2515 post-renderer with output-dir-template (skipped for Helm 4)"
-    test_pass "issue-2515 post-renderer with output-dir-template (skipped for Helm 4)"
+    test_start "issue-2515 post-renderer with output-dir-template (Helm 4)"
+    info "Installing filter post-renderer plugin for Helm 4"
+    ${helm} plugin uninstall filter &>/dev/null || true
+    ${helm} plugin install ${issue_2515_case_dir}/input/helm-plugin-filter ${PLUGIN_INSTALL_FLAGS} || fail "Failed to install filter plugin"
+    issue_2515_postrenderer_arg="filter"
 else
     test_start "issue-2515 post-renderer with output-dir-template"
-    info "Testing that --post-renderer output is written to files when --output-dir-template is set"
+    issue_2515_postrenderer_arg="${issue_2515_case_dir}/input/filter.bash"
+fi
 
-    issue_2515_output_dir="${issue_2515_tmp}/output"
+info "Testing that --post-renderer output is written to files when --output-dir-template is set"
 
-    ${helmfile} -f ${issue_2515_case_dir}/input/helmfile.yaml \
-        template \
-        --post-renderer ${issue_2515_case_dir}/input/filter.bash \
-        --output-dir-template "${issue_2515_output_dir}/{{.Release.Name}}" \
-        &> ${issue_2515_tmp}/log || fail "helmfile template should not fail"
+issue_2515_output_dir="${issue_2515_tmp}/output"
 
-    issue_2515_templates_dir="${issue_2515_output_dir}/issue-2515/templates"
-    if [ ! -d "${issue_2515_templates_dir}" ]; then
-        fail "Expected templates directory ${issue_2515_templates_dir} to exist"
-    fi
+${helmfile} -f ${issue_2515_case_dir}/input/helmfile.yaml \
+    template \
+    --post-renderer ${issue_2515_postrenderer_arg} \
+    --output-dir-template "${issue_2515_output_dir}/{{.Release.Name}}" \
+    &> ${issue_2515_tmp}/log || fail "helmfile template should not fail"
 
-    issue_2515_output_file=$(find "${issue_2515_templates_dir}" -type f \( -name '*.yaml' -o -name '*.yml' \) | head -n 1)
-    if [ -z "${issue_2515_output_file}" ]; then
-        fail "Expected rendered YAML file under ${issue_2515_templates_dir}"
-    fi
+issue_2515_templates_dir="${issue_2515_output_dir}/issue-2515/templates"
+if [ ! -d "${issue_2515_templates_dir}" ]; then
+    fail "Expected templates directory ${issue_2515_templates_dir} to exist"
+fi
 
-    if grep -q "original-cm" "${issue_2515_output_file}"; then
-        fail "Output should contain post-renderer output (Namespace), not original templates (original-cm). File contents: $(cat ${issue_2515_output_file})"
-    fi
+issue_2515_output_file=$(find "${issue_2515_templates_dir}" -type f \( -name '*.yaml' -o -name '*.yml' \) | head -n 1)
+if [ -z "${issue_2515_output_file}" ]; then
+    fail "Expected rendered YAML file under ${issue_2515_templates_dir}"
+fi
 
-    if ! grep -q "postrendered" "${issue_2515_output_file}"; then
-        fail "Output should contain post-renderer content (namespace postrendered). File contents: $(cat ${issue_2515_output_file})"
-    fi
+if grep -q "original-cm" "${issue_2515_output_file}"; then
+    fail "Output should contain post-renderer output (Namespace), not original templates (original-cm). File contents: $(cat ${issue_2515_output_file})"
+fi
 
+if ! grep -q "postrendered" "${issue_2515_output_file}"; then
+    fail "Output should contain post-renderer content (namespace postrendered). File contents: $(cat ${issue_2515_output_file})"
+fi
+
+if [ "${HELMFILE_HELM4}" = "1" ]; then
+    test_pass "issue-2515 post-renderer with output-dir-template (Helm 4)"
+else
     test_pass "issue-2515 post-renderer with output-dir-template"
 fi

test/integration/test-cases/issue-2515/input/helm-plugin-filter/filter.sh

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+# Discard stdin (pre-rendered content) and output a fixed Namespace resource.
+# This verifies that the post-renderer output — not the original templates — is
+# written to the output directory.
+cat > /dev/null
+printf -- "---\napiVersion: v1\nkind: Namespace\nmetadata:\n  name: postrendered\n"

test/integration/test-cases/issue-2515/input/helm-plugin-filter/plugin.yaml

@@ -0,0 +1,8 @@
+apiVersion: v1
+type: postrenderer/v1
+name: filter
+version: 0.1.0
+runtime: subprocess
+runtimeConfig:
+  platformCommand:
+    - command: ${HELM_PLUGIN_DIR}/filter.sh