feat: NSIS Windows installer and update check (#32)

- windows/installer.nsi: installs to Program Files, manages system PATH, registers uninstaller - relspec update [--check] [--yes]: compares against the latest release and prompts; on Windows downloads and runs the installer - release workflow builds and uploads relspec-setup-windows-amd64.exe - make installer-windows
2026-10-03 21:44:08 +02:00
parent b49859537b
commit 02a394c99d
9 changed files with 621 additions and 1 deletions
@@ -78,6 +78,13 @@ jobs:
            echo "Built $NAME"
          done

+      - name: Build Windows installer
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y nsis
+          VERSION="${{ github.event.inputs.tag || github.ref_name }}"
+          makensis -DVERSION="${VERSION#v}" -DEXE="$PWD/relspec-windows-amd64.exe" -DOUT="$PWD/relspec-setup-windows-amd64.exe" windows/installer.nsi
+
      - name: Create release and upload assets
        run: |
          TAG="${{ github.event.inputs.tag || github.ref_name }}"
@@ -1,4 +1,4 @@
-.PHONY: all build test test-unit test-integration lint coverage clean install help docker-up docker-down docker-test docker-test-integration start stop release release-version rerelease godoc vet fmt fmt-check staticcheck govulncheck check
+.PHONY: installer-windows all build test test-unit test-integration lint coverage clean install help docker-up docker-down docker-test docker-test-integration start stop release release-version rerelease godoc vet fmt fmt-check staticcheck govulncheck check

 # Binary name
 BINARY_NAME=relspec
@@ -270,3 +270,8 @@ rerelease: lint fmt-check ## Move the latest tag to HEAD and force push it

 help: ## Display this help screen
 	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-20s\033[0m %s\n", $$1, $$2}'
+
+installer-windows: ## Build the Windows binary and NSIS installer (requires makensis)
+	@echo "Building Windows installer..."
+	GOOS=windows GOARCH=amd64 $(GOBUILD) -trimpath -ldflags "$(LDFLAGS)" -o $(BUILD_DIR)/relspec-windows-amd64.exe ./cmd/relspec
+	makensis -DVERSION=$$(cat VERSION | tr -d '[:space:]') -DEXE=$(CURDIR)/$(BUILD_DIR)/relspec-windows-amd64.exe -DOUT=$(CURDIR)/$(BUILD_DIR)/relspec-setup-windows-amd64.exe windows/installer.nsi
@@ -51,6 +51,7 @@ func init() {
 	rootCmd.AddCommand(mergeCmd)
 	rootCmd.AddCommand(splitCmd)
 	rootCmd.AddCommand(versionCmd)
+	rootCmd.AddCommand(updateCmd)
 	rootCmd.AddCommand(reportCmd)
 	rootCmd.PersistentFlags().BoolVar(&prisma7, "prisma7", false, "Use Prisma 7 generator conventions when reading/writing Prisma schemas")
 	rootCmd.PersistentFlags().StringArrayVar(&typeMapFlags, "type-map", nil, "Override a SQL-to-Go type mapping for bun/gorm output as sqltype=gotype (repeatable), e.g. --type-map uuid=uuid.UUID --type-map numeric=decimal.Decimal")
@@ -0,0 +1,148 @@
+package main
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"time"
+
+	"github.com/spf13/cobra"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/buildinfo"
+	"git.warky.dev/wdevs/relspecgo/pkg/updatecheck"
+)
+
+// windowsInstallerAsset is the release asset built by the NSIS installer step.
+const windowsInstallerAsset = "relspec-setup-windows-amd64.exe"
+
+var (
+	updateCheckOnly bool
+	updateAssumeYes bool
+	updateAPIURL    = updatecheck.DefaultAPIURL
+)
+
+var updateCmd = &cobra.Command{
+	Use:   "update",
+	Short: "Check for a newer release and offer to install it",
+	Long: `Check the project releases for a version newer than this binary.
+
+If one exists you are prompted to update. On Windows the installer is
+downloaded and started; on other platforms the release page URL is shown.
+Use --check to only report, and --yes to skip the prompt.`,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		ctx, cancel := context.WithTimeout(cmd.Context(), 10*time.Minute)
+		defer cancel()
+		return runUpdate(ctx, updateOptions{
+			current:   buildinfo.Version,
+			apiURL:    updateAPIURL,
+			goos:      runtime.GOOS,
+			checkOnly: updateCheckOnly,
+			assumeYes: updateAssumeYes,
+			in:        cmd.InOrStdin(),
+			out:       cmd.OutOrStdout(),
+			install:   downloadAndRunInstaller,
+		})
+	},
+}
+
+func init() {
+	updateCmd.Flags().BoolVar(&updateCheckOnly, "check", false, "Only report whether an update is available")
+	updateCmd.Flags().BoolVarP(&updateAssumeYes, "yes", "y", false, "Update without prompting")
+}
+
+type updateOptions struct {
+	current   string
+	apiURL    string
+	goos      string
+	checkOnly bool
+	assumeYes bool
+	in        io.Reader
+	out       io.Writer
+	// install downloads and starts the installer found at url.
+	install func(ctx context.Context, url string, out io.Writer) error
+}
+
+func runUpdate(ctx context.Context, o updateOptions) error {
+	rel, err := updatecheck.Latest(ctx, nil, o.apiURL)
+	if err != nil {
+		return err
+	}
+
+	if !updatecheck.IsNewer(o.current, rel.Tag) {
+		_, _ = fmt.Fprintf(o.out, "RelSpec %s is up to date (latest release: %s)\n", o.current, rel.Tag)
+		return nil
+	}
+
+	_, _ = fmt.Fprintf(o.out, "A newer RelSpec is available: %s (installed: %s)\n", rel.Tag, o.current)
+	if o.checkOnly {
+		_, _ = fmt.Fprintf(o.out, "Release: %s\n", rel.URL)
+		return nil
+	}
+
+	installer, canInstall := rel.FindAsset(windowsInstallerAsset)
+	if o.goos != "windows" || !canInstall {
+		_, _ = fmt.Fprintf(o.out, "Download it from: %s\n", rel.URL)
+		return nil
+	}
+
+	if !o.assumeYes && !confirm(o.in, o.out, "Download and run the installer now?") {
+		_, _ = fmt.Fprintf(o.out, "Skipped. Release: %s\n", rel.URL)
+		return nil
+	}
+	return o.install(ctx, installer.URL, o.out)
+}
+
+// confirm asks a yes/no question, defaulting to no.
+func confirm(in io.Reader, out io.Writer, question string) bool {
+	_, _ = fmt.Fprintf(out, "%s [y/N]: ", question)
+	line, _ := bufio.NewReader(in).ReadString('\n')
+	switch strings.ToLower(strings.TrimSpace(line)) {
+	case "y", "yes":
+		return true
+	}
+	return false
+}
+
+// downloadAndRunInstaller saves the installer to a temp directory and starts
+// it detached so this process can exit and release relspec.exe.
+func downloadAndRunInstaller(ctx context.Context, url string, out io.Writer) error {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return err
+	}
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return fmt.Errorf("downloading installer: %w", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("downloading installer: unexpected status %s", resp.Status)
+	}
+
+	dir, err := os.MkdirTemp("", "relspec-update-")
+	if err != nil {
+		return err
+	}
+	path := filepath.Join(dir, windowsInstallerAsset)
+	f, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	if _, err := io.Copy(f, resp.Body); err != nil {
+		_ = f.Close()
+		return fmt.Errorf("downloading installer: %w", err)
+	}
+	if err := f.Close(); err != nil {
+		return err
+	}
+
+	_, _ = fmt.Fprintf(out, "Starting installer: %s\n", path)
+	return exec.Command(path).Start()
+}
@@ -0,0 +1,110 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func releaseServer(t *testing.T, tag string, withInstaller bool) *httptest.Server {
+	t.Helper()
+	assets := ""
+	if withInstaller {
+		assets = fmt.Sprintf(`{"name":%q,"browser_download_url":"https://x/setup.exe"}`, windowsInstallerAsset)
+	}
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, _ = fmt.Fprintf(w, `{"tag_name":%q,"html_url":"https://x/release","assets":[%s]}`, tag, assets)
+	}))
+	t.Cleanup(srv.Close)
+	return srv
+}
+
+func TestRunUpdate(t *testing.T) {
+	tests := []struct {
+		name          string
+		current       string
+		latest        string
+		withInstaller bool
+		goos          string
+		checkOnly     bool
+		assumeYes     bool
+		stdin         string
+		wantOut       []string
+		wantInstall   bool
+	}{
+		{name: "up to date", current: "v1.0.5", latest: "v1.0.5", goos: "windows", withInstaller: true, wantOut: []string{"up to date"}},
+		{name: "dev build never prompts", current: "dev", latest: "v9.0.0", goos: "windows", withInstaller: true, wantOut: []string{"up to date"}},
+		{name: "check only", current: "v1.0.5", latest: "v1.0.6", goos: "windows", withInstaller: true, checkOnly: true, wantOut: []string{"v1.0.6", "https://x/release"}},
+		{name: "non-windows shows url", current: "v1.0.5", latest: "v1.0.6", goos: "linux", withInstaller: true, wantOut: []string{"Download it from: https://x/release"}},
+		{name: "windows without installer asset", current: "v1.0.5", latest: "v1.0.6", goos: "windows", wantOut: []string{"Download it from"}},
+		{name: "windows prompt yes", current: "v1.0.5", latest: "v1.0.6", goos: "windows", withInstaller: true, stdin: "y\n", wantOut: []string{"[y/N]"}, wantInstall: true},
+		{name: "windows prompt no", current: "v1.0.5", latest: "v1.0.6", goos: "windows", withInstaller: true, stdin: "n\n", wantOut: []string{"Skipped"}},
+		{name: "windows prompt empty", current: "v1.0.5", latest: "v1.0.6", goos: "windows", withInstaller: true, wantOut: []string{"Skipped"}},
+		{name: "windows --yes", current: "v1.0.5", latest: "v1.0.6", goos: "windows", withInstaller: true, assumeYes: true, wantInstall: true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			srv := releaseServer(t, tt.latest, tt.withInstaller)
+			var out bytes.Buffer
+			var installedURL string
+			err := runUpdate(context.Background(), updateOptions{
+				current: tt.current, apiURL: srv.URL, goos: tt.goos,
+				checkOnly: tt.checkOnly, assumeYes: tt.assumeYes,
+				in: strings.NewReader(tt.stdin), out: &out,
+				install: func(_ context.Context, url string, _ io.Writer) error {
+					installedURL = url
+					return nil
+				},
+			})
+			if err != nil {
+				t.Fatal(err)
+			}
+			for _, want := range tt.wantOut {
+				if !strings.Contains(out.String(), want) {
+					t.Errorf("output missing %q:\n%s", want, out.String())
+				}
+			}
+			if (installedURL != "") != tt.wantInstall {
+				t.Errorf("installer called = %v, want %v", installedURL != "", tt.wantInstall)
+			}
+			if tt.wantInstall && installedURL != "https://x/setup.exe" {
+				t.Errorf("installer url = %q", installedURL)
+			}
+		})
+	}
+}
+
+func TestRunUpdate_Errors(t *testing.T) {
+	bad := httptest.NewServer(http.NotFoundHandler())
+	defer bad.Close()
+	if err := runUpdate(context.Background(), updateOptions{current: "v1.0.0", apiURL: bad.URL, out: io.Discard}); err == nil {
+		t.Error("expected lookup error")
+	}
+
+	srv := releaseServer(t, "v1.0.6", true)
+	want := errors.New("boom")
+	err := runUpdate(context.Background(), updateOptions{
+		current: "v1.0.5", apiURL: srv.URL, goos: "windows", assumeYes: true, out: io.Discard,
+		install: func(context.Context, string, io.Writer) error { return want },
+	})
+	if !errors.Is(err, want) {
+		t.Errorf("err = %v", err)
+	}
+}
+
+func TestDownloadAndRunInstaller_BadStatus(t *testing.T) {
+	srv := httptest.NewServer(http.NotFoundHandler())
+	defer srv.Close()
+	if err := downloadAndRunInstaller(context.Background(), srv.URL, io.Discard); err == nil {
+		t.Error("expected error for non-200")
+	}
+	if err := downloadAndRunInstaller(context.Background(), "://bad", io.Discard); err == nil {
+		t.Error("expected error for bad url")
+	}
+}
@@ -0,0 +1,115 @@
+// Package updatecheck looks up the latest RelSpec release on the project's
+// Gitea instance and compares it against the running version.
+package updatecheck
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// DefaultAPIURL is the Gitea endpoint that returns the latest release.
+const DefaultAPIURL = "https://git.warky.dev/api/v1/repos/wdevs/relspecgo/releases/latest"
+
+// Asset is a downloadable file attached to a release.
+type Asset struct {
+	Name string `json:"name"`
+	URL  string `json:"browser_download_url"`
+}
+
+// Release is the subset of the Gitea release payload that is needed.
+type Release struct {
+	Tag    string  `json:"tag_name"`
+	URL    string  `json:"html_url"`
+	Assets []Asset `json:"assets"`
+}
+
+// Latest fetches the latest release from apiURL. A nil client uses a client
+// with a 10 second timeout.
+func Latest(ctx context.Context, client *http.Client, apiURL string) (*Release, error) {
+	if client == nil {
+		client = &http.Client{Timeout: 10 * time.Second}
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, apiURL, nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Accept", "application/json")
+
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("checking for updates: %w", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("checking for updates: unexpected status %s", resp.Status)
+	}
+
+	var rel Release
+	if err := json.NewDecoder(resp.Body).Decode(&rel); err != nil {
+		return nil, fmt.Errorf("decoding release: %w", err)
+	}
+	if rel.Tag == "" {
+		return nil, fmt.Errorf("release has no tag")
+	}
+	return &rel, nil
+}
+
+// FindAsset returns the first asset with the given name.
+func (r *Release) FindAsset(name string) (Asset, bool) {
+	for _, a := range r.Assets {
+		if a.Name == name {
+			return a, true
+		}
+	}
+	return Asset{}, false
+}
+
+// IsNewer reports whether latest is a higher version than current. Versions
+// that are not dotted numbers (for example "dev" or a commit hash) are never
+// considered outdated, so development builds are not nagged.
+func IsNewer(current, latest string) bool {
+	cur, ok := parseVersion(current)
+	if !ok {
+		return false
+	}
+	lat, ok := parseVersion(latest)
+	if !ok {
+		return false
+	}
+	for i := range cur {
+		if lat[i] != cur[i] {
+			return lat[i] > cur[i]
+		}
+	}
+	return false
+}
+
+// parseVersion parses "v1.2.3" style versions into three numeric parts.
+// Missing parts are zero; any pre-release or build suffix is ignored.
+func parseVersion(v string) ([3]int, bool) {
+	var out [3]int
+	v = strings.TrimPrefix(strings.TrimSpace(v), "v")
+	if i := strings.IndexAny(v, "-+ "); i >= 0 {
+		v = v[:i]
+	}
+	if v == "" {
+		return out, false
+	}
+	parts := strings.Split(v, ".")
+	if len(parts) > 3 {
+		return out, false
+	}
+	for i, p := range parts {
+		n, err := strconv.Atoi(p)
+		if err != nil || n < 0 {
+			return out, false
+		}
+		out[i] = n
+	}
+	return out, true
+}
@@ -0,0 +1,94 @@
+package updatecheck
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestIsNewer(t *testing.T) {
+	tests := []struct {
+		name            string
+		current, latest string
+		want            bool
+	}{
+		{"patch bump", "v1.0.85", "v1.0.86", true},
+		{"minor beats patch", "v1.0.99", "v1.1.0", true},
+		{"major bump", "v1.9.9", "v2.0.0", true},
+		{"numeric not lexical", "v1.0.9", "v1.0.10", true},
+		{"same", "v1.0.85", "v1.0.85", false},
+		{"older latest", "v1.0.86", "v1.0.85", false},
+		{"no v prefix", "1.0.1", "v1.0.2", true},
+		{"short version", "v1.0", "v1.0.1", true},
+		{"prerelease suffix ignored", "v1.0.1-rc1", "v1.0.2", true},
+		{"dev build", "dev", "v9.9.9", false},
+		{"commit hash", "abc1234", "v9.9.9", false},
+		{"empty current", "", "v1.0.0", false},
+		{"bad latest", "v1.0.0", "latest", false},
+		{"too many parts", "v1.0.0.0", "v1.0.1", false},
+		{"negative", "v1.-1.0", "v1.0.0", false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := IsNewer(tt.current, tt.latest); got != tt.want {
+				t.Errorf("IsNewer(%q,%q) = %v, want %v", tt.current, tt.latest, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestLatest(t *testing.T) {
+	tests := []struct {
+		name    string
+		status  int
+		body    string
+		wantTag string
+		wantErr bool
+	}{
+		{"ok", 200, `{"tag_name":"v1.2.3","html_url":"https://x/r","assets":[{"name":"a.exe","browser_download_url":"https://x/a.exe"}]}`, "v1.2.3", false},
+		{"not found", 404, `{}`, "", true},
+		{"bad json", 200, `{`, "", true},
+		{"missing tag", 200, `{"html_url":"u"}`, "", true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(tt.status)
+				_, _ = w.Write([]byte(tt.body))
+			}))
+			defer srv.Close()
+
+			rel, err := Latest(context.Background(), nil, srv.URL)
+			if (err != nil) != tt.wantErr {
+				t.Fatalf("err = %v, wantErr %v", err, tt.wantErr)
+			}
+			if err == nil {
+				if rel.Tag != tt.wantTag {
+					t.Errorf("tag = %q", rel.Tag)
+				}
+				if a, ok := rel.FindAsset("a.exe"); !ok || a.URL != "https://x/a.exe" {
+					t.Errorf("asset = %+v %v", a, ok)
+				}
+				if _, ok := rel.FindAsset("missing"); ok {
+					t.Error("unexpected asset")
+				}
+			}
+		})
+	}
+}
+
+func TestLatestUnreachable(t *testing.T) {
+	srv := httptest.NewServer(http.NotFoundHandler())
+	url := srv.URL
+	srv.Close()
+	if _, err := Latest(context.Background(), nil, url); err == nil {
+		t.Error("expected error for unreachable server")
+	}
+}
+
+func TestLatestBadURL(t *testing.T) {
+	if _, err := Latest(context.Background(), nil, "://bad"); err == nil {
+		t.Error("expected error for bad URL")
+	}
+}
@@ -0,0 +1,29 @@
+# Windows installer
+
+NSIS script: `installer.nsi`. Output: `build/relspec-setup-windows-amd64.exe`.
+
+## Build
+
+```
+make installer-windows
+```
+
+Needs `makensis` (package `nsis`). CI builds and uploads it on release.
+
+## Installer
+
+- Installs `relspec.exe` to `%ProgramFiles%\RelSpec` (admin).
+- Adds the install dir to the system `PATH`; removed on uninstall.
+- Registers in Add/Remove Programs.
+
+## Update check
+
+```
+relspec update            # check, prompt, download + run installer (Windows)
+relspec update --check    # report only
+relspec update --yes      # no prompt
+```
+
+- Source: latest Gitea release (`pkg/updatecheck`).
+- `dev` and commit-hash builds are never reported as outdated.
+- Non-Windows: prints the release URL.
@@ -0,0 +1,111 @@
+; RelSpec Windows installer (NSIS)
+;
+; Build: makensis -DVERSION=1.2.3 -DEXE=<abs path to relspec.exe> -DOUT=<abs path to installer> windows/installer.nsi
+; Use absolute paths for EXE and OUT; relative ones resolve unpredictably.
+
+!ifndef VERSION
+  !define VERSION "0.0.0"
+!endif
+!ifndef OUT
+  !define OUT "relspec-setup-windows-amd64.exe"
+!endif
+!ifndef EXE
+  !define EXE "relspec-windows-amd64.exe"
+!endif
+
+!define APPNAME   "RelSpec"
+!define REGKEY    "Software\Microsoft\Windows\CurrentVersion\Uninstall\RelSpec"
+!define ENVKEY    "SYSTEM\CurrentControlSet\Control\Session Manager\Environment"
+
+Unicode true
+Name "${APPNAME} ${VERSION}"
+OutFile "${OUT}"
+InstallDir "$PROGRAMFILES64\${APPNAME}"
+InstallDirRegKey HKLM "Software\${APPNAME}" "InstallDir"
+RequestExecutionLevel admin
+SetCompressor /SOLID lzma
+
+VIProductVersion "${VERSION}.0"
+VIAddVersionKey "ProductName" "${APPNAME}"
+VIAddVersionKey "FileDescription" "${APPNAME} installer"
+VIAddVersionKey "FileVersion" "${VERSION}"
+VIAddVersionKey "ProductVersion" "${VERSION}"
+
+!include "MUI2.nsh"
+!include "LogicLib.nsh"
+!include "StrFunc.nsh"
+!include "WinMessages.nsh"
+${StrStr}
+${StrRep}
+${UnStrRep}
+
+!insertmacro MUI_PAGE_WELCOME
+!insertmacro MUI_PAGE_DIRECTORY
+!insertmacro MUI_PAGE_INSTFILES
+!insertmacro MUI_PAGE_FINISH
+!insertmacro MUI_UNPAGE_CONFIRM
+!insertmacro MUI_UNPAGE_INSTFILES
+!insertmacro MUI_LANGUAGE "English"
+
+Section "Install"
+  SetRegView 64
+  SetOutPath "$INSTDIR"
+  File "/oname=relspec.exe" "${EXE}"
+  WriteUninstaller "$INSTDIR\uninstall.exe"
+
+  WriteRegStr HKLM "Software\${APPNAME}" "InstallDir" "$INSTDIR"
+  WriteRegStr HKLM "${REGKEY}" "DisplayName" "${APPNAME}"
+  WriteRegStr HKLM "${REGKEY}" "DisplayVersion" "${VERSION}"
+  WriteRegStr HKLM "${REGKEY}" "Publisher" "Warky Devs"
+  WriteRegStr HKLM "${REGKEY}" "DisplayIcon" "$INSTDIR\relspec.exe"
+  WriteRegStr HKLM "${REGKEY}" "InstallLocation" "$INSTDIR"
+  WriteRegStr HKLM "${REGKEY}" "UninstallString" '"$INSTDIR\uninstall.exe"'
+  WriteRegDWORD HKLM "${REGKEY}" "NoModify" 1
+  WriteRegDWORD HKLM "${REGKEY}" "NoRepair" 1
+
+  ; Add the install directory to the system PATH unless it is already there.
+  ReadRegStr $0 HKLM "${ENVKEY}" "Path"
+  ${StrStr} $1 ";$0;" ";$INSTDIR;"
+  ${If} $1 == ""
+    StrLen $2 $0
+    ${If} $2 > 900
+      ; NSIS strings are limited; rewriting a very long PATH could truncate it.
+      MessageBox MB_OK|MB_ICONEXCLAMATION "PATH is too long to update automatically. Add $INSTDIR to PATH manually."
+    ${Else}
+      ${If} $0 == ""
+        WriteRegExpandStr HKLM "${ENVKEY}" "Path" "$INSTDIR"
+      ${Else}
+        WriteRegExpandStr HKLM "${ENVKEY}" "Path" "$0;$INSTDIR"
+      ${EndIf}
+      SendMessage ${HWND_BROADCAST} ${WM_WININICHANGE} 0 "STR:Environment" /TIMEOUT=5000
+    ${EndIf}
+  ${EndIf}
+SectionEnd
+
+Section "Uninstall"
+  SetRegView 64
+  Delete "$INSTDIR\relspec.exe"
+  Delete "$INSTDIR\uninstall.exe"
+  RMDir "$INSTDIR"
+
+  ; Remove the install directory from the system PATH.
+  ReadRegStr $0 HKLM "${ENVKEY}" "Path"
+  ; Wrap in separators so every entry, including the first and last, matches.
+  StrCpy $1 ";$0;"
+  ${UnStrRep} $1 "$1" ";$INSTDIR;" ";"
+  StrCpy $2 $1 1
+  ${If} $2 == ";"
+    StrCpy $1 $1 "" 1
+  ${EndIf}
+  StrCpy $2 $1 1 -1
+  ${If} $2 == ";"
+    StrCpy $1 $1 -1
+  ${EndIf}
+  ${If} $1 != $0
+    WriteRegExpandStr HKLM "${ENVKEY}" "Path" "$1"
+    SendMessage ${HWND_BROADCAST} ${WM_WININICHANGE} 0 "STR:Environment" /TIMEOUT=5000
+  ${EndIf}
+
+  DeleteRegKey HKLM "${REGKEY}"
+  DeleteRegKey HKLM "Software\${APPNAME}"
+SectionEnd