[v2, dev] Build frontend only before starting the dev watcher command (#1694)

* [v2, dev] Improve logging of dev watcher command during stop

* [v2, dev] Build frontend only before starting the dev watcher command

Breaking Change: Ignore flags take precedence over Force flag.

v2/cmd/wails/internal/commands/dev/dev.go

@@ -16,10 +16,10 @@ import (
 	"runtime"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"syscall"
 	"time"
 
-	"github.com/bitfield/script"
 	"github.com/google/shlex"
 	"github.com/wailsapp/wails/v2/cmd/wails/internal"
 	"github.com/wailsapp/wails/v2/internal/gomod"
@@ -186,23 +186,15 @@ func AddSubcommand(app *clir.Cli, w io.Writer) error {
 		signal.Notify(quitChannel, os.Interrupt, os.Kill, syscall.SIGTERM)
 		exitCodeChannel := make(chan int, 1)
 
-		// Install if needed
+		// Build the frontend if requested, but ignore building the application itself.
-		if installCommand := projectConfig.GetDevInstallerCommand(); installCommand != "" {
+		ignoreFrontend := buildOptions.IgnoreFrontend
-			// Install initial frontend dev dependencies
+		if !ignoreFrontend {
-			err = os.Chdir(filepath.Join(cwd, "frontend"))
+			logger.Println("Building frontend for development...")
-			if err != nil {
+			buildOptions.IgnoreApplication = true
-				return err
+			if _, err := build.Build(buildOptions); err != nil {
-			}
-			LogGreen("Installing frontend dependencies...")
-			pipe := script.Exec(installCommand)
-			pipe.Wait()
-			if pipe.Error() != nil {
-				return pipe.Error()
-			}
-			err = os.Chdir(cwd)
-			if err != nil {
 				return err
 			}
+			buildOptions.IgnoreApplication = false
 		}
 
 		// frontend:dev:watcher command.
@@ -218,9 +210,11 @@ func AddSubcommand(app *clir.Cli, w io.Writer) error {
 			defer closer()
 		}
 
-		// Do initial build
+		// Do initial build but only for the application.
 		logger.Println("Building application for development...")
+		buildOptions.IgnoreFrontend = true
 		debugBinaryProcess, appBinary, err := restartApp(buildOptions, nil, flags, exitCodeChannel)
+		buildOptions.IgnoreFrontend = ignoreFrontend || flags.frontendDevServerURL != ""
 		if err != nil {
 			return err
 		}
@@ -473,19 +467,30 @@ func runFrontendDevWatcherCommand(cwd string, devCommand string, discoverViteSer
 	LogGreen("Running frontend DevWatcher command: '%s'", devCommand)
 	var wg sync.WaitGroup
 	wg.Add(1)
+
+	const (
+		stateRunning   int32 = 0
+		stateCanceling       = 1
+		stateStopped         = 2
+	)
+	state := stateRunning
 	go func() {
 		if err := cmd.Wait(); err != nil {
-			if err.Error() != "exit status 1" {
+			wasRunning := atomic.CompareAndSwapInt32(&state, stateRunning, stateStopped)
+			if err.Error() != "exit status 1" && wasRunning {
 				LogRed("Error from DevWatcher '%s': %s", devCommand, err.Error())
 			}
 		}
+		atomic.StoreInt32(&state, stateStopped)
 		LogGreen("DevWatcher command exited!")
 		wg.Done()
 	}()
 
 	return func() {
-		killProc(cmd, devCommand)
+		if atomic.CompareAndSwapInt32(&state, stateRunning, stateCanceling) {
-		LogGreen("DevWatcher command killed!")
+			LogGreen("Killing DevWatcher command...")
+			killProc(cmd, devCommand)
+		}
 		cancel()
 		wg.Wait()
 	}, viteServerURL, nil
@@ -674,7 +679,6 @@ func doWatcherLoop(buildOptions *build.Options, debugBinaryProcess *process.Proc
 				rebuild = false
 				LogGreen("[Rebuild triggered] files updated")
 				// Try and build the app
-				buildOptions.IgnoreFrontend = flags.skipFrontend || flags.frontendDevServerURL != ""
 				newBinaryProcess, _, err := restartApp(buildOptions, debugBinaryProcess, flags, exitCodeChannel)
 				if err != nil {
 					LogRed("Error during build: %s", err.Error())

v2/pkg/commands/build/build.go

@@ -42,6 +42,7 @@ type Options struct {
 	Compiler            string               // The compiler command to use
 	SkipModTidy         bool                 //  Skip mod tidy before compile
 	IgnoreFrontend      bool                 // Indicates if the frontend does not need building
+	IgnoreApplication   bool                 // Indicates if the application does not need building
 	OutputFile          string               // Override the output filename
 	BuildDirectory      string               // Directory to use for building the application
 	CleanBuildDirectory bool                 // Indicates if the build directory should be cleaned before building
@@ -125,13 +126,35 @@ func Build(options *Options) (string, error) {
 		}
 	}
 
-	if !options.IgnoreFrontend || options.ForceBuild {
+	if !options.IgnoreFrontend {
 		err = builder.BuildFrontend(outputLogger)
 		if err != nil {
 			return "", err
 		}
 	}
 
+	compileBinary := ""
+	if !options.IgnoreApplication {
+		compileBinary, err = execBuildApplication(builder, options)
+		if err != nil {
+			return "", err
+		}
+	}
+
+	hookArgs["${bin}"] = compileBinary
+	for _, hook := range []string{options.Platform + "/" + options.Arch, options.Platform + "/*", "*/*"} {
+		if err := execPostBuildHook(outputLogger, options, hook, hookArgs); err != nil {
+			return "", err
+		}
+	}
+
+	return compileBinary, nil
+}
+
+func execBuildApplication(builder Builder, options *Options) (string, error) {
+	// Extract logger
+	outputLogger := options.Logger
+
 	// If we are building for windows, we will need to generate the asset bundle before
 	// compilation. This will be a .syso file in the project root
 	if options.Pack && options.Platform == "windows" {
@@ -166,8 +189,7 @@ func Build(options *Options) (string, error) {
 		if options.Verbosity == VERBOSE {
 			outputLogger.Println("\nBuilding AMD64 Target: %s", filepath.Join(options.BuildDirectory, options.OutputFile))
 		}
-		err = builder.CompileProject(options)
+		err := builder.CompileProject(options)
-
 		if err != nil {
 			return "", err
 		}
@@ -200,10 +222,10 @@ func Build(options *Options) (string, error) {
 		if err != nil {
 			return "", err
 		}
-		projectData.OutputFilename = outputFile
+		options.ProjectData.OutputFilename = outputFile
 		options.CompiledBinary = filepath.Join(options.BuildDirectory, outputFile)
 	} else {
-		err = builder.CompileProject(options)
+		err := builder.CompileProject(options)
 		if err != nil {
 			return "", err
 		}
@@ -217,23 +239,14 @@ func Build(options *Options) (string, error) {
 		outputLogger.Print("  - Packaging application: ")
 
 		// TODO: Allow cross platform build
-		err = packageProject(options, runtime.GOOS)
+		err := packageProject(options, runtime.GOOS)
 		if err != nil {
 			return "", err
 		}
 		outputLogger.Println("Done.")
 	}
 
-	compileBinary := options.CompiledBinary
+	return options.CompiledBinary, nil
-	hookArgs["${bin}"] = compileBinary
-
-	for _, hook := range []string{options.Platform + "/" + options.Arch, options.Platform + "/*", "*/*"} {
-		if err := execPostBuildHook(outputLogger, options, hook, hookArgs); err != nil {
-			return "", err
-		}
-	}
-
-	return compileBinary, nil
 }
 
 func execPreBuildHook(outputLogger *clilogger.CLILogger, options *Options, hookIdentifier string, argReplacements map[string]string) error {