fix: poc

integration/examples/lifecycle-hooks/k8s-pod.yaml

@@ -2,6 +2,8 @@ apiVersion: v1
 kind: Pod
 metadata:
   name: getting-started
+  labels:
+    tier: test-1
 spec:
   containers:
   - name: getting-started

integration/examples/lifecycle-hooks/post-render.sh

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+sed -e 's/test-1/test-2/g' < /dev/stdin

integration/examples/lifecycle-hooks/skaffold.yaml

@@ -9,7 +9,7 @@ manifests:
           command: ["sh", "-c", "echo pre-render host hook running on $(hostname)!"]
     after:
       - host:
-          command: ["sh", "-c", "echo post-render host hook running on $(hostname)!"]
+          command: ["sh", "post-render.sh", ]
 build:
   hooks:
     before:

pkg/skaffold/hooks/render.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"github.com/GoogleContainerTools/skaffold/v2/pkg/skaffold/output/log"
 	"io"
 	"strings"
 	"sync"
@@ -81,6 +82,9 @@ func (r renderRunner) RunPostHooks(ctx context.Context, list manifest.ManifestLi
 				if err := hook.run(ctx, in, &b); err != nil {
 					return manifest.ManifestList{}, err
 				}
+				if b.Len() == 0 {
+					return manifest.ManifestList{}, fmt.Errorf("the length of stdout should be greater than 0 when using render post hook with change")
+				}
 				in = &b
 			} else {
 				if err := hook.run(ctx, in, out); err != nil {
@@ -92,7 +96,9 @@ func (r renderRunner) RunPostHooks(ctx context.Context, list manifest.ManifestLi
 	if len(r.PostHooks) > 0 {
 		output.Default.Fprintln(out, fmt.Sprintf("Completed %s hooks", phases.PostRender))
 	}
+	log.Entry(context.TODO()).Debugf("Original manifests: %s\n", list.String())
 	updated, err := manifest.Load(in)
+	log.Entry(context.TODO()).Debugf("Updated manifests: %s\n", updated.String())
 	if err != nil {
 		return manifest.ManifestList{}, err
 	}

pkg/skaffold/render/renderer/render_mux.go

@@ -85,7 +85,7 @@ func (r RenderMux) Render(ctx context.Context, out io.Writer, artifacts []graph.
 		return allManifests, nil
 	}
 
-	updated := manifest.ManifestListByConfig{}
+	updated := manifest.NewManifestListByConfig()
 	for _, name := range allManifests.ConfigNames() {
 		list := allManifests.GetForConfig(name)
 		for _, hr := range r.gr.HookRunners {