internal/lsp, internal/tool: clean up command line of gopls

Descriptions of certain commands were changed to not start with capital
letter.

All of the commands were splitted into so called main
commands and feature commands.

Package tool did have a limitation that revealed itself when command
was invoked only with `-h`, i.e. `gopls -h`. Limitation was that in
above mentioned case, FlagSet.Parse() was intercepting `-h` flag and
printing just default usage.

Updates golang/go#35855

Change-Id: I9bd27fc72e8fb8d18025d95ebcae974dd5583e91
Reviewed-on: https://go-review.googlesource.com/c/tools/+/210359
Run-TryBot: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Cottrell <iancottrell@google.com>

internal/lsp/cmd/cmd.go

@@ -61,10 +61,10 @@ type Application struct {
 	Remote string `flag:"remote" help:"*EXPERIMENTAL* - forward all commands to a remote lsp"`
 
 	// Enable verbose logging
-	Verbose bool `flag:"v" help:"Verbose output"`
+	Verbose bool `flag:"v" help:"verbose output"`
 
 	// Control ocagent export of telemetry
-	OCAgent string `flag:"ocagent" help:"The address of the ocagent, or off"`
+	OCAgent string `flag:"ocagent" help:"the address of the ocagent, or off"`
 
 	// PrepareOptions is called to update the options when a new view is built.
 	// It is primarily to allow the behavior of gopls to be modified by hooks.
@@ -101,9 +101,22 @@ func (app *Application) ShortHelp() string {
 // This includes the short help for all the sub commands.
 func (app *Application) DetailedHelp(f *flag.FlagSet) {
 	fmt.Fprint(f.Output(), `
+gopls is a Go language server. It is typically used with an editor to provide
+language features. When no command is specified, gopls will default to the 'serve'
+command. The language features can also be accessed via the gopls command-line interface.
+
 Available commands are:
+`, app.Name(), app.Name(), app.Serve.Name())
+	fmt.Fprint(f.Output(), `
+main:
 `)
-	for _, c := range app.commands() {
+	for _, c := range app.mainCommands() {
+		fmt.Fprintf(f.Output(), "  %s : %v\n", c.Name(), c.ShortHelp())
+	}
+	fmt.Fprint(f.Output(), `
+features:
+`)
+	for _, c := range app.featureCommands() {
 		fmt.Fprintf(f.Output(), "  %s : %v\n", c.Name(), c.ShortHelp())
 	}
 	fmt.Fprint(f.Output(), `
@@ -138,9 +151,22 @@ func (app *Application) Run(ctx context.Context, args ...string) error {
 // command line.
 // The command is specified by the first non flag argument.
 func (app *Application) commands() []tool.Application {
+	var commands []tool.Application
+	commands = append(commands, app.mainCommands()...)
+	commands = append(commands, app.featureCommands()...)
+	return commands
+}
+
+func (app *Application) mainCommands() []tool.Application {
 	return []tool.Application{
 		&app.Serve,
+		&version{app: app},
 		&bug{},
+	}
+}
+
+func (app *Application) featureCommands() []tool.Application {
+	return []tool.Application{
 		&check{app: app},
 		&foldingRanges{app: app},
 		&format{app: app},
@@ -154,7 +180,6 @@ func (app *Application) commands() []tool.Application {
 		&signature{app: app},
 		&suggestedfix{app: app},
 		&symbols{app: app},
-		&version{app: app},
 	}
 }
 

internal/lsp/cmd/serve.go

@@ -34,8 +34,8 @@ type Serve struct {
 	Mode    string `flag:"mode" help:"no effect"`
 	Port    int    `flag:"port" help:"port on which to run gopls for debugging purposes"`
 	Address string `flag:"listen" help:"address on which to listen for remote connections"`
-	Trace   bool   `flag:"rpc.trace" help:"Print the full rpc trace in lsp inspector format"`
+	Trace   bool   `flag:"rpc.trace" help:"print the full rpc trace in lsp inspector format"`
-	Debug   string `flag:"debug" help:"Serve debug information on the supplied address"`
+	Debug   string `flag:"debug" help:"serve debug information on the supplied address"`
 
 	app *Application
 }

internal/tool/tool.go

@@ -102,6 +102,11 @@ func Main(ctx context.Context, app Application, args []string) {
 // error.
 func Run(ctx context.Context, app Application, args []string) error {
 	s := flag.NewFlagSet(app.Name(), flag.ExitOnError)
+	s.Usage = func() {
+		fmt.Fprint(s.Output(), app.ShortHelp())
+		fmt.Fprintf(s.Output(), "\n\nUsage: %v [flags] %v\n", app.Name(), app.Usage())
+		app.DetailedHelp(s)
+	}
 	p := addFlags(s, reflect.StructField{}, reflect.ValueOf(app))
 	s.Parse(args)