build: ship bootstrapper Go along with builder for PPA (#26731)

build/checksums.txt

@@ -41,3 +41,6 @@ c4f58b7e227b9fd41f0e9310dc83f4a4e7d026598e2f6e95b78761081a6d9bd2  golangci-lint-
 eb57f9bcb56646f2e3d6ccaf02ec227815fb05077b2e0b1bf9e755805acdc2b9  golangci-lint-1.51.1-windows-arm64.zip
 bce02f7232723cb727755ee11f168a700a00896a25d37f87c4b173bce55596b4  golangci-lint-1.51.1-windows-armv6.zip
 cf6403f84707ce8c98664736772271bc8874f2e760c2fd0f00cf3e85963507e9  golangci-lint-1.51.1-windows-armv7.zip
+
+# This is the builder on PPA that will build Go itself (inception-y), don't modify!
+9419cc70dc5a2523f29a77053cafff658ed21ef3561d9b6b020280ebceab28b9  go1.19.src.tar.gz

build/ci.go

@@ -136,10 +136,18 @@ var (
 		"golang-go":   "/usr/lib/go",
 	}
 
-	// This is the version of go that will be downloaded by
+	// This is the version of Go that will be downloaded by
 	//
 	//     go run ci.go install -dlgo
 	dlgoVersion = "1.20.1"
+
+	// This is the version of Go that will be used to bootstrap the PPA builder.
+	//
+	// This version is fine to be old and full of security holes, we just use it
+	// to build the latest Go. Don't change it. If it ever becomes infufficient,
+	// we need to switch over to a recursive builder to jumpt across supported
+	// versions.
+	gobootVersion = "1.19"
 )
 
 var GOBIN, _ = filepath.Abs(filepath.Join("build", "bin"))
@@ -655,10 +663,11 @@ func doDebianSource(cmdline []string) {
 		gpg.Stdin = bytes.NewReader(key)
 		build.MustRun(gpg)
 	}
-
-	// Download and verify the Go source package.
-	gobundle := downloadGoSources(*cachedir)
-
+	// Download and verify the Go source packages.
+	var (
+		gobootbundle = downloadGoBootstrapSources(*cachedir)
+		gobundle     = downloadGoSources(*cachedir)
+	)
 	// Download all the dependencies needed to build the sources and run the ci script
 	srcdepfetch := tc.Go("mod", "download")
 	srcdepfetch.Env = append(srcdepfetch.Env, "GOPATH="+filepath.Join(*workdir, "modgopath"))
@@ -675,12 +684,19 @@ func doDebianSource(cmdline []string) {
 			meta := newDebMetadata(distro, goboot, *signer, env, now, pkg.Name, pkg.Version, pkg.Executables)
 			pkgdir := stageDebianSource(*workdir, meta)
 
-			// Add Go source code
+			// Add bootstrapper Go source code
+			if err := build.ExtractArchive(gobootbundle, pkgdir); err != nil {
+				log.Fatalf("Failed to extract bootstrapper Go sources: %v", err)
+			}
+			if err := os.Rename(filepath.Join(pkgdir, "go"), filepath.Join(pkgdir, ".goboot")); err != nil {
+				log.Fatalf("Failed to rename bootstrapper Go source folder: %v", err)
+			}
+			// Add builder Go source code
 			if err := build.ExtractArchive(gobundle, pkgdir); err != nil {
-				log.Fatalf("Failed to extract Go sources: %v", err)
+				log.Fatalf("Failed to extract builder Go sources: %v", err)
 			}
 			if err := os.Rename(filepath.Join(pkgdir, "go"), filepath.Join(pkgdir, ".go")); err != nil {
-				log.Fatalf("Failed to rename Go source folder: %v", err)
+				log.Fatalf("Failed to rename builder Go source folder: %v", err)
 			}
 			// Add all dependency modules in compressed form
 			os.MkdirAll(filepath.Join(pkgdir, ".mod", "cache"), 0755)
@@ -709,6 +725,19 @@ func doDebianSource(cmdline []string) {
 	}
 }
 
+// downloadGoBootstrapSources downloads the Go source tarball that will be used
+// to bootstrap the builder Go.
+func downloadGoBootstrapSources(cachedir string) string {
+	csdb := build.MustLoadChecksums("build/checksums.txt")
+	file := fmt.Sprintf("go%s.src.tar.gz", gobootVersion)
+	url := "https://dl.google.com/go/" + file
+	dst := filepath.Join(cachedir, file)
+	if err := csdb.DownloadFile(url, dst); err != nil {
+		log.Fatal(err)
+	}
+	return dst
+}
+
 // downloadGoSources downloads the Go source tarball.
 func downloadGoSources(cachedir string) string {
 	csdb := build.MustLoadChecksums("build/checksums.txt")

build/deb/ethereum/deb.rules

@@ -16,6 +16,11 @@ override_dh_auto_build:
 	# We can't download a fresh Go within Launchpad, so we're shipping and building
 	# one on the fly. However, we can't build it inside the go-ethereum folder as
 	# bootstrapping clashes with go modules, so build in a sibling folder.
+	#
+	# We're also shipping the bootstrapper as of Go 1.20 as it had minimum version
+	# requirements opposed to older versions of Go.
+	(mv .goboot ../ && cd ../.goboot/src && ./make.bash)
+	(cd ../.goboot/bin && export GOROOT_BOOTSTRAP=`pwd`)
 	(mv .go ../ && cd ../.go/src && ./make.bash)
 
 	# We can't download external go modules within Launchpad, so we're shipping the