main.go

Documentation: cmd/go

     1  // Copyright 2011 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:generate ./mkalldocs.sh
     6  
     7  package main
     8  
     9  import (
    10  	"context"
    11  	"flag"
    12  	"fmt"
    13  	"internal/buildcfg"
    14  	"log"
    15  	"os"
    16  	"path/filepath"
    17  	"runtime"
    18  	"strings"
    19  
    20  	"cmd/go/internal/base"
    21  	"cmd/go/internal/bug"
    22  	"cmd/go/internal/cfg"
    23  	"cmd/go/internal/clean"
    24  	"cmd/go/internal/doc"
    25  	"cmd/go/internal/envcmd"
    26  	"cmd/go/internal/fix"
    27  	"cmd/go/internal/fmtcmd"
    28  	"cmd/go/internal/generate"
    29  	"cmd/go/internal/get"
    30  	"cmd/go/internal/help"
    31  	"cmd/go/internal/list"
    32  	"cmd/go/internal/modcmd"
    33  	"cmd/go/internal/modfetch"
    34  	"cmd/go/internal/modget"
    35  	"cmd/go/internal/modload"
    36  	"cmd/go/internal/run"
    37  	"cmd/go/internal/test"
    38  	"cmd/go/internal/tool"
    39  	"cmd/go/internal/trace"
    40  	"cmd/go/internal/version"
    41  	"cmd/go/internal/vet"
    42  	"cmd/go/internal/work"
    43  )
    44  
    45  func init() {
    46  	base.Go.Commands = []*base.Command{
    47  		bug.CmdBug,
    48  		work.CmdBuild,
    49  		clean.CmdClean,
    50  		doc.CmdDoc,
    51  		envcmd.CmdEnv,
    52  		fix.CmdFix,
    53  		fmtcmd.CmdFmt,
    54  		generate.CmdGenerate,
    55  		modget.CmdGet,
    56  		work.CmdInstall,
    57  		list.CmdList,
    58  		modcmd.CmdMod,
    59  		run.CmdRun,
    60  		test.CmdTest,
    61  		tool.CmdTool,
    62  		version.CmdVersion,
    63  		vet.CmdVet,
    64  
    65  		help.HelpBuildConstraint,
    66  		help.HelpBuildmode,
    67  		help.HelpC,
    68  		help.HelpCache,
    69  		help.HelpEnvironment,
    70  		help.HelpFileType,
    71  		modload.HelpGoMod,
    72  		help.HelpGopath,
    73  		get.HelpGopathGet,
    74  		modfetch.HelpGoproxy,
    75  		help.HelpImportPath,
    76  		modload.HelpModules,
    77  		modget.HelpModuleGet,
    78  		modfetch.HelpModuleAuth,
    79  		help.HelpPackages,
    80  		modfetch.HelpPrivate,
    81  		test.HelpTestflag,
    82  		test.HelpTestfunc,
    83  		modget.HelpVCS,
    84  	}
    85  }
    86  
    87  func main() {
    88  	_ = go11tag
    89  	flag.Usage = base.Usage
    90  	flag.Parse()
    91  	log.SetFlags(0)
    92  
    93  	args := flag.Args()
    94  	if len(args) < 1 {
    95  		base.Usage()
    96  	}
    97  
    98  	if args[0] == "get" || args[0] == "help" {
    99  		if !modload.WillBeEnabled() {
   100  			// Replace module-aware get with GOPATH get if appropriate.
   101  			*modget.CmdGet = *get.CmdGet
   102  		}
   103  	}
   104  
   105  	cfg.CmdName = args[0] // for error messages
   106  	if args[0] == "help" {
   107  		help.Help(os.Stdout, args[1:])
   108  		return
   109  	}
   110  
   111  	// Diagnose common mistake: GOPATH==GOROOT.
   112  	// This setting is equivalent to not setting GOPATH at all,
   113  	// which is not what most people want when they do it.
   114  	if gopath := cfg.BuildContext.GOPATH; filepath.Clean(gopath) == filepath.Clean(runtime.GOROOT()) {
   115  		fmt.Fprintf(os.Stderr, "warning: GOPATH set to GOROOT (%s) has no effect\n", gopath)
   116  	} else {
   117  		for _, p := range filepath.SplitList(gopath) {
   118  			// Some GOPATHs have empty directory elements - ignore them.
   119  			// See issue 21928 for details.
   120  			if p == "" {
   121  				continue
   122  			}
   123  			// Note: using HasPrefix instead of Contains because a ~ can appear
   124  			// in the middle of directory elements, such as /tmp/git-1.8.2~rc3
   125  			// or C:\PROGRA~1. Only ~ as a path prefix has meaning to the shell.
   126  			if strings.HasPrefix(p, "~") {
   127  				fmt.Fprintf(os.Stderr, "go: GOPATH entry cannot start with shell metacharacter '~': %q\n", p)
   128  				os.Exit(2)
   129  			}
   130  			if !filepath.IsAbs(p) {
   131  				if cfg.Getenv("GOPATH") == "" {
   132  					// We inferred $GOPATH from $HOME and did a bad job at it.
   133  					// Instead of dying, uninfer it.
   134  					cfg.BuildContext.GOPATH = ""
   135  				} else {
   136  					fmt.Fprintf(os.Stderr, "go: GOPATH entry is relative; must be absolute path: %q.\nFor more details see: 'go help gopath'\n", p)
   137  					os.Exit(2)
   138  				}
   139  			}
   140  		}
   141  	}
   142  
   143  	if fi, err := os.Stat(cfg.GOROOT); err != nil || !fi.IsDir() {
   144  		fmt.Fprintf(os.Stderr, "go: cannot find GOROOT directory: %v\n", cfg.GOROOT)
   145  		os.Exit(2)
   146  	}
   147  
   148  BigCmdLoop:
   149  	for bigCmd := base.Go; ; {
   150  		for _, cmd := range bigCmd.Commands {
   151  			if cmd.Name() != args[0] {
   152  				continue
   153  			}
   154  			if len(cmd.Commands) > 0 {
   155  				bigCmd = cmd
   156  				args = args[1:]
   157  				if len(args) == 0 {
   158  					help.PrintUsage(os.Stderr, bigCmd)
   159  					base.SetExitStatus(2)
   160  					base.Exit()
   161  				}
   162  				if args[0] == "help" {
   163  					// Accept 'go mod help' and 'go mod help foo' for 'go help mod' and 'go help mod foo'.
   164  					help.Help(os.Stdout, append(strings.Split(cfg.CmdName, " "), args[1:]...))
   165  					return
   166  				}
   167  				cfg.CmdName += " " + args[0]
   168  				continue BigCmdLoop
   169  			}
   170  			if !cmd.Runnable() {
   171  				continue
   172  			}
   173  			invoke(cmd, args)
   174  			base.Exit()
   175  			return
   176  		}
   177  		helpArg := ""
   178  		if i := strings.LastIndex(cfg.CmdName, " "); i >= 0 {
   179  			helpArg = " " + cfg.CmdName[:i]
   180  		}
   181  		fmt.Fprintf(os.Stderr, "go %s: unknown command\nRun 'go help%s' for usage.\n", cfg.CmdName, helpArg)
   182  		base.SetExitStatus(2)
   183  		base.Exit()
   184  	}
   185  }
   186  
   187  func invoke(cmd *base.Command, args []string) {
   188  	// 'go env' handles checking the build config
   189  	if cmd != envcmd.CmdEnv {
   190  		buildcfg.Check()
   191  	}
   192  
   193  	// Set environment (GOOS, GOARCH, etc) explicitly.
   194  	// In theory all the commands we invoke should have
   195  	// the same default computation of these as we do,
   196  	// but in practice there might be skew
   197  	// This makes sure we all agree.
   198  	cfg.OrigEnv = os.Environ()
   199  	cfg.CmdEnv = envcmd.MkEnv()
   200  	for _, env := range cfg.CmdEnv {
   201  		if os.Getenv(env.Name) != env.Value {
   202  			os.Setenv(env.Name, env.Value)
   203  		}
   204  	}
   205  
   206  	cmd.Flag.Usage = func() { cmd.Usage() }
   207  	if cmd.CustomFlags {
   208  		args = args[1:]
   209  	} else {
   210  		base.SetFromGOFLAGS(&cmd.Flag)
   211  		cmd.Flag.Parse(args[1:])
   212  		args = cmd.Flag.Args()
   213  	}
   214  	ctx := maybeStartTrace(context.Background())
   215  	ctx, span := trace.StartSpan(ctx, fmt.Sprint("Running ", cmd.Name(), " command"))
   216  	cmd.Run(ctx, cmd, args)
   217  	span.Done()
   218  }
   219  
   220  func init() {
   221  	base.Usage = mainUsage
   222  }
   223  
   224  func mainUsage() {
   225  	help.PrintUsage(os.Stderr, base.Go)
   226  	os.Exit(2)
   227  }
   228  
   229  func maybeStartTrace(pctx context.Context) context.Context {
   230  	if cfg.DebugTrace == "" {
   231  		return pctx
   232  	}
   233  
   234  	ctx, close, err := trace.Start(pctx, cfg.DebugTrace)
   235  	if err != nil {
   236  		base.Fatalf("failed to start trace: %v", err)
   237  	}
   238  	base.AtExit(func() {
   239  		if err := close(); err != nil {
   240  			base.Fatalf("failed to stop trace: %v", err)
   241  		}
   242  	})
   243  
   244  	return ctx
   245  }
   246
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