cmd/go: delete 'go doc'

It's next to useless and confusing as well. Let's make godoc better instead.

Fixes #4849.

R=golang-dev, dsymonds, adg, rogpeppe, rsc
CC=golang-dev
https://golang.org/cl/12974043

src/cmd/go/doc.go

@@ -16,7 +16,6 @@ The commands are:
 
     build       compile packages and dependencies
     clean       remove object files
-    doc         run godoc on package sources
     env         print Go environment information
     fix         run go tool fix on packages
     fmt         run gofmt on package sources
@@ -162,26 +161,6 @@ The -x flag causes clean to print remove commands as it executes them.
 For more about specifying packages, see 'go help packages'.
 
 
-Run godoc on package sources
-
-Usage:
-
-	go doc [-n] [-x] [packages]
-
-Doc runs the godoc command on the packages named by the
-import paths.
-
-For more about godoc, see 'godoc godoc'.
-For more about specifying packages, see 'go help packages'.
-
-The -n flag prints commands that would be executed.
-The -x flag prints commands as they are executed.
-
-To run godoc with specific options, run godoc itself.
-
-See also: go fix, go fmt, go vet.
-
-
 Print Go environment information
 
 Usage:
@@ -229,7 +208,7 @@ The -x flag prints commands as they are executed.
 
 To run gofmt with specific options, run gofmt itself.
 
-See also: go doc, go fix, go vet.
+See also: go fix, go vet.
 
 
 Download and install packages and dependencies
@@ -880,5 +859,3 @@ See the documentation of the testing package for more information.
 
 */
 package main
-
-// NOTE: cmdDoc is in fmt.go.

src/cmd/go/fmt.go

@@ -4,11 +4,8 @@
 
 package main
 
-import "os/exec"
-
 func init() {
 	addBuildFlagsNX(cmdFmt)
-	addBuildFlagsNX(cmdDoc)
 }
 
 var cmdFmt = &Command{
@@ -27,7 +24,7 @@ The -x flag prints commands as they are executed.
 
 To run gofmt with specific options, run gofmt itself.
 
-See also: go doc, go fix, go vet.
+See also: go fix, go vet.
 	`,
 }
 
@@ -39,42 +36,3 @@ func runFmt(cmd *Command, args []string) {
 		run(stringList("gofmt", "-l", "-w", relPaths(pkg.allgofiles)))
 	}
 }
-
-var cmdDoc = &Command{
-	Run:       runDoc,
-	UsageLine: "doc [-n] [-x] [packages]",
-	Short:     "run godoc on package sources",
-	Long: `
-Doc runs the godoc command on the packages named by the
-import paths.
-
-For more about godoc, see 'godoc godoc'.
-For more about specifying packages, see 'go help packages'.
-
-The -n flag prints commands that would be executed.
-The -x flag prints commands as they are executed.
-
-To run godoc with specific options, run godoc itself.
-
-See also: go fix, go fmt, go vet.
-	`,
-}
-
-func runDoc(cmd *Command, args []string) {
-	_, err := exec.LookPath("godoc")
-	if err != nil {
-		errorf("go doc: can't find godoc; to install:\n\tgo get code.google.com/p/go.tools/cmd/godoc")
-		return
-	}
-	for _, pkg := range packages(args) {
-		if pkg.ImportPath == "command-line arguments" {
-			errorf("go doc: cannot use package file list")
-			continue
-		}
-		if pkg.local {
-			run("godoc", pkg.Dir)
-		} else {
-			run("godoc", pkg.ImportPath)
-		}
-	}
-}

src/cmd/go/main.go

@@ -76,7 +76,6 @@ func (c *Command) Runnable() bool {
 var commands = []*Command{
 	cmdBuild,
 	cmdClean,
-	cmdDoc,
 	cmdEnv,
 	cmdFix,
 	cmdFmt,
@@ -213,8 +212,6 @@ var documentationTemplate = `// Copyright 2011 The Go Authors.  All rights reser
 
 {{end}}*/
 package main
-
-// NOTE: cmdDoc is in fmt.go.
 `
 
 // tmpl executes the given template text on data, writing the result to w.