Remove dead code for EOL stacks (heroku-18, heroku-20)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: ipmb

builder/build/appjson.go

@@ -32,27 +32,6 @@ const DefaultStack = "heroku-22"
 
 // buildpacks included in builder
 var IncludedBuildpacks = map[string][]string{
-	"heroku-20": {
-		// $ pack builder inspect heroku/buildpacks:20 -o json | jq '.remote_info.buildpacks[].id'
-		"heroku/builder-eol-warning",
-		"heroku/go",
-		"heroku/gradle",
-		"heroku/java",
-		"heroku/jvm",
-		"heroku/maven",
-		"heroku/nodejs",
-		"heroku/nodejs-corepack",
-		"heroku/nodejs-engine",
-		"heroku/nodejs-npm-engine",
-		"heroku/nodejs-npm-install",
-		"heroku/nodejs-pnpm-install",
-		"heroku/nodejs-yarn",
-		"heroku/php",
-		"heroku/procfile",
-		"heroku/python",
-		"heroku/ruby",
-		"heroku/scala",
-	},
 	"heroku-22": {
 		// $ pack builder inspect heroku/builder:22 -o json | jq '.remote_info.buildpacks[].id'
 		"heroku/deb-packages",
@@ -143,12 +122,6 @@ func ParseAppJson(ctx context.Context) (*AppJSON, error) {
 // the first item in the list is the builder, followed by the stack image
 // the stack image is only used for prefetching, so non-heroku stacks should still work
 func (a *AppJSON) GetBuilders() []string {
-	if a.Stack == "heroku-18" {
-		return []string{"heroku/buildpacks:18", "heroku/heroku:18-cnb"}
-	}
-	if a.Stack == "heroku-20" {
-		return []string{"heroku/buildpacks:20", "heroku/heroku:20-cnb"}
-	}
 	if a.Stack == "heroku-22" {
 		return []string{"heroku/builder:22", "heroku/heroku:22-cnb"}
 	}

builder/build/appjson_test.go

@@ -8,7 +8,6 @@ import (
 	"testing"
 
 	"github.com/rs/zerolog"
-	"github.com/rs/zerolog/log"
 )
 
 func stringSliceEqual(a, b []string) bool {
@@ -25,21 +24,6 @@ func stringSliceEqual(a, b []string) bool {
 
 var testContext = zerolog.New(os.Stdout).With().Timestamp().Logger().WithContext(context.Background())
 
-func TestAppJsonBuildpackPatch(t *testing.T) {
-	a := AppJSON{
-		Buildpacks: []Buildpack{
-			{URL: "heroku/nodejs"},
-			{URL: "heroku/python"},
-		},
-		Stack: "heroku-20",
-		ctx:   log.With().Logger().WithContext(context.Background()),
-	}
-	expected := []string{"urn:cnb:builder:heroku/nodejs", "urn:cnb:builder:heroku/python"}
-	if !stringSliceEqual(a.GetBuildpacks(), expected) {
-		t.Errorf("expected %s, got %s", expected, a.GetBuildpacks())
-	}
-}
-
 func TestAppJsonMissing(t *testing.T) {
 	a := AppJSON{
 		reader: func() ([]byte, error) {
@@ -77,8 +61,6 @@ func TestAppJsonBuilders(t *testing.T) {
 		stack    string
 		expected []string
 	}{
-		{"heroku-18", []string{"heroku/buildpacks:18", "heroku/heroku:18-cnb"}},
-		{"heroku-20", []string{"heroku/buildpacks:20", "heroku/heroku:20-cnb"}},
 		{"heroku-22", []string{"heroku/builder:22", "heroku/heroku:22-cnb"}},
 		{"custom/builder:latest", []string{"custom/builder:latest"}},
 	}