[code-cleanup] Rename devbox.Writer to Stderr (#1507)

## Summary

This renames the devbox `Writer` field to the more accurate `Stderr`. It
changes a few functions that used to print stuff and now they return
strings instead.

Also renamed a few functions that where called `PrintX` to something
more accurate because they don't actually print anything.

How to review:

* grep for `devopt.Opts` this will show all the places where we used to
pass in stdout sometimes. Specifically @mohsenari please look at
integrate.go. @ipince please look at telemetry.go. I think both of these
were wrong.
* Please take a look at functions that used to print stuff and now
return strings (i.e. Info and PrintGlobalList). I tried to keep
formatting identical so nothing should change.

## How was it tested?

compiles

devbox.go

@@ -16,41 +16,36 @@ import (
 
 // Devbox provides an isolated development environment.
 type Devbox interface {
-	// Add adds Nix packages to the config so that they're available in the devbox
-	// environment. It validates that the Nix packages exist, and install them.
-	// Adding duplicate packages is a no-op.
 	Add(ctx context.Context, platforms, excludePlatforms []string, pkgs ...string) error
 	Config() *devconfig.Config
-	ProjectDir() string
-	// Generate creates the directory of Nix files and the Dockerfile that define
-	// the devbox environment.
-	Generate(ctx context.Context) error
-	GenerateDevcontainer(ctx context.Context, generateOpts devopt.GenerateOpts) error
-	GenerateDockerfile(ctx context.Context, generateOpts devopt.GenerateOpts) error
-	GenerateEnvrcFile(ctx context.Context, force bool, envFlags devopt.EnvFlags) error
-	Info(ctx context.Context, pkg string, markdown bool) error
+	EnvVars(ctx context.Context) ([]string, error)
+	Info(ctx context.Context, pkg string, markdown bool) (string, error)
 	Install(ctx context.Context) error
 	IsEnvEnabled() bool
 	ListScripts() []string
-	PrintEnv(ctx context.Context, includeHooks bool) (string, error)
-	PrintEnvVars(ctx context.Context) ([]string, error)
-	PrintGlobalList() error
+	NixEnv(ctx context.Context, includeHooks bool) (string, error)
+	PackageNames() []string
+	ProjectDir() string
 	Pull(ctx context.Context, opts devopt.PullboxOpts) error
 	Push(ctx context.Context, opts devopt.PullboxOpts) error
-	// Remove removes Nix packages from the config so that it no longer exists in
-	// the devbox environment.
 	Remove(ctx context.Context, pkgs ...string) error
-	RestartServices(ctx context.Context, services ...string) error
 	RunScript(ctx context.Context, scriptName string, scriptArgs []string) error
-	Services() (services.Services, error)
-	// Shell generates the devbox environment and launches nix-shell as a child process.
 	Shell(ctx context.Context) error
+	Update(ctx context.Context, opts devopt.UpdateOpts) error
+
+	// Interact with services
+	ListServices(ctx context.Context) error
+	RestartServices(ctx context.Context, services ...string) error
+	Services() (services.Services, error)
 	StartProcessManager(ctx context.Context, requestedServices []string, background bool, processComposeFileOrDir string) error
 	StartServices(ctx context.Context, services ...string) error
 	StopServices(ctx context.Context, allProjects bool, services ...string) error
-	ListServices(ctx context.Context) error
 
-	Update(ctx context.Context, opts devopt.UpdateOpts) error
+	// Generate files
+	Generate(ctx context.Context) error
+	GenerateDevcontainer(ctx context.Context, generateOpts devopt.GenerateOpts) error
+	GenerateDockerfile(ctx context.Context, generateOpts devopt.GenerateOpts) error
+	GenerateEnvrcFile(ctx context.Context, force bool, envFlags devopt.EnvFlags) error
 }
 
 // Open opens a devbox by reading the config file in dir.

internal/boxcli/add.go

@@ -66,7 +66,7 @@ func addCmd() *cobra.Command {
 func addCmdFunc(cmd *cobra.Command, args []string, flags addCmdFlags) error {
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:               flags.config.path,
-		Writer:            cmd.ErrOrStderr(),
+		Stderr:            cmd.ErrOrStderr(),
 		AllowInsecureAdds: flags.allowInsecure,
 	})
 	if err != nil {

internal/boxcli/cloud.go

@@ -142,7 +142,7 @@ func runCloudShellCmd(cmd *cobra.Command, flags *cloudShellCmdFlags) error {
 
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    flags.config.path,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)
@@ -158,7 +158,7 @@ func runCloudInit(cmd *cobra.Command, flags *cloudShellCmdFlags) error {
 
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    flags.config.path,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)

internal/boxcli/generate.go

@@ -139,7 +139,7 @@ func runGenerateCmd(cmd *cobra.Command, flags *generateCmdFlags) error {
 	// Check the directory exists.
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    flags.config.path,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)
@@ -167,7 +167,7 @@ func runGenerateDirenvCmd(cmd *cobra.Command, flags *generateCmdFlags) error {
 
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    flags.config.path,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)

internal/boxcli/global.go

@@ -68,12 +68,15 @@ func listGlobalCmdFunc(cmd *cobra.Command, args []string) error {
 
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    path,
-		Writer: cmd.OutOrStdout(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)
 	}
-	return box.PrintGlobalList()
+	for _, p := range box.PackageNames() {
+		fmt.Fprintf(cmd.OutOrStdout(), "* %s\n", p)
+	}
+	return nil
 }
 
 var globalConfigPath string
@@ -125,7 +128,7 @@ func ensureGlobalEnvEnabled(cmd *cobra.Command, args []string) error {
 
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    path,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return err

internal/boxcli/info.go

@@ -4,6 +4,8 @@
 package boxcli
 
 import (
+	"fmt"
+
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 
@@ -36,11 +38,16 @@ func infoCmd() *cobra.Command {
 func infoCmdFunc(cmd *cobra.Command, pkg string, flags infoCmdFlags) error {
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    flags.config.path,
-		Writer: cmd.OutOrStdout(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)
 	}
 
-	return box.Info(cmd.Context(), pkg, flags.markdown)
+	info, err := box.Info(cmd.Context(), pkg, flags.markdown)
+	if err != nil {
+		return errors.WithStack(err)
+	}
+	fmt.Fprint(cmd.OutOrStdout(), info)
+	return nil
 }

internal/boxcli/install.go

@@ -34,7 +34,7 @@ func installCmdFunc(cmd *cobra.Command, flags runCmdFlags) error {
 	// Check the directory exists.
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    flags.config.path,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)

internal/boxcli/integrate.go

@@ -75,13 +75,13 @@ func runIntegrateVSCodeCmd(cmd *cobra.Command) error {
 	// todo: add error handling - consider sending error message to parent process
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    message.ConfigDir,
-		Writer: cmd.OutOrStdout(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return err
 	}
 	// Get env variables of a devbox shell
-	envVars, err := box.PrintEnvVars(cmd.Context())
+	envVars, err := box.EnvVars(cmd.Context())
 	if err != nil {
 		return err
 	}

internal/boxcli/midcobra/telemetry.go

@@ -94,7 +94,7 @@ func getPackagesAndCommitHash(c *cobra.Command) ([]string, string) {
 
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:            path,
-		Writer:         os.Stdout,
+		Stderr:         os.Stderr,
 		IgnoreWarnings: true,
 	})
 	if err != nil {

internal/boxcli/pull.go

@@ -50,7 +50,7 @@ func pullCmd() *cobra.Command {
 func pullCmdFunc(cmd *cobra.Command, url string, flags *pullCmdFlags) error {
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    flags.config.path,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)

internal/boxcli/push.go

@@ -36,7 +36,7 @@ func pushCmd() *cobra.Command {
 func pushCmdFunc(cmd *cobra.Command, url string, flags pushCmdFlags) error {
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    flags.config.path,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)

internal/boxcli/rm.go

@@ -33,7 +33,7 @@ func removeCmd() *cobra.Command {
 func runRemoveCmd(cmd *cobra.Command, args []string, flags removeCmdFlags) error {
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    flags.config.path,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)

internal/boxcli/root.go

@@ -37,6 +37,9 @@ func RootCmd() *cobra.Command {
 	command := &cobra.Command{
 		Use:   "devbox",
 		Short: "Instant, easy, predictable development environments",
+		// Warning, PersistentPreRunE is not called if a subcommand also declares
+		// it. TODO: Figure out a better way to implement this so that subcommands
+		// can't accidentally override it.
 		PersistentPreRun: func(cmd *cobra.Command, args []string) {
 			if flags.quiet {
 				cmd.SetErr(io.Discard)
@@ -49,6 +52,7 @@ func RootCmd() *cobra.Command {
 		SilenceErrors: true,
 		SilenceUsage:  true,
 	}
+
 	// Stable commands
 	command.AddCommand(addCmd())
 	if featureflag.Auth.Enabled() {

internal/boxcli/run.go

@@ -61,7 +61,7 @@ func runCmd() *cobra.Command {
 func listScripts(cmd *cobra.Command, flags runCmdFlags) []string {
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:            flags.config.path,
-		Writer:         cmd.ErrOrStderr(),
+		Stderr:         cmd.ErrOrStderr(),
 		Pure:           flags.pure,
 		IgnoreWarnings: true,
 	})
@@ -108,7 +108,7 @@ func runScriptCmd(cmd *cobra.Command, args []string, flags runCmdFlags) error {
 	// Check the directory exists.
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:                     path,
-		Writer:                  cmd.ErrOrStderr(),
+		Stderr:                  cmd.ErrOrStderr(),
 		Pure:                    flags.pure,
 		Env:                     env,
 		OmitBinWrappersFromPath: omitBinWrappersFromPath,

internal/boxcli/services.go

@@ -116,7 +116,7 @@ func servicesCmd(persistentPreRunE ...cobraFunc) *cobra.Command {
 func listServices(cmd *cobra.Command, flags servicesCmdFlags) error {
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    flags.config.path,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)
@@ -133,7 +133,7 @@ func startServices(cmd *cobra.Command, services []string, flags servicesCmdFlags
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    flags.config.path,
 		Env:    env,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)
@@ -155,7 +155,7 @@ func stopServices(
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    servicesFlags.config.path,
 		Env:    env,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)
@@ -178,7 +178,7 @@ func restartServices(
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    flags.config.path,
 		Env:    env,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)
@@ -201,7 +201,7 @@ func startProcessManager(
 		Dir:                      servicesFlags.config.path,
 		Env:                      env,
 		CustomProcessComposeFile: flags.processComposeFile,
-		Writer:                   cmd.ErrOrStderr(),
+		Stderr:                   cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)

internal/boxcli/shell.go

@@ -57,7 +57,7 @@ func runShellCmd(cmd *cobra.Command, flags shellCmdFlags) error {
 		Dir:    flags.config.path,
 		Env:    env,
 		Pure:   flags.pure,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)
@@ -66,7 +66,7 @@ func runShellCmd(cmd *cobra.Command, flags shellCmdFlags) error {
 	if flags.printEnv {
 		// false for includeHooks is because init hooks is not compatible with .envrc files generated
 		// by versions older than 0.4.6
-		script, err := box.PrintEnv(cmd.Context(), false /*includeHooks*/)
+		script, err := box.NixEnv(cmd.Context(), false /*includeHooks*/)
 		if err != nil {
 			return err
 		}

internal/boxcli/shellenv.go

@@ -60,7 +60,7 @@ func shellEnvFunc(cmd *cobra.Command, flags shellEnvCmdFlags) (string, error) {
 	}
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    flags.config.path,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 		Pure:   flags.pure,
 		Env:    env,
 	})
@@ -74,7 +74,7 @@ func shellEnvFunc(cmd *cobra.Command, flags shellEnvCmdFlags) (string, error) {
 		}
 	}
 
-	envStr, err := box.PrintEnv(cmd.Context(), flags.runInitHook)
+	envStr, err := box.NixEnv(cmd.Context(), flags.runInitHook)
 	if err != nil {
 		return "", err
 	}

internal/boxcli/update.go

@@ -47,7 +47,7 @@ func updateCmd() *cobra.Command {
 func updateCmdFunc(cmd *cobra.Command, args []string, flags *updateCmdFlags) error {
 	box, err := devbox.Open(&devopt.Opts{
 		Dir:    flags.config.path,
-		Writer: cmd.ErrOrStderr(),
+		Stderr: cmd.ErrOrStderr(),
 	})
 	if err != nil {
 		return errors.WithStack(err)