run.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  // Package run implements the “go run” command.
     6  package run
     7  
     8  import (
     9  	"context"
    10  	"go/build"
    11  	"path/filepath"
    12  	"strings"
    13  
    14  	"cmd/go/internal/base"
    15  	"cmd/go/internal/cfg"
    16  	"cmd/go/internal/load"
    17  	"cmd/go/internal/modload"
    18  	"cmd/go/internal/str"
    19  	"cmd/go/internal/work"
    20  )
    21  
    22  var CmdRun = &base.Command{
    23  	UsageLine: "go run [build flags] [-exec xprog] package [arguments...]",
    24  	Short:     "compile and run Go program",
    25  	Long: `
    26  Run compiles and runs the named main Go package.
    27  Typically the package is specified as a list of .go source files from a single
    28  directory, but it may also be an import path, file system path, or pattern
    29  matching a single known package, as in 'go run .' or 'go run my/cmd'.
    30  
    31  If the package argument has a version suffix (like @latest or @v1.0.0),
    32  "go run" builds the program in module-aware mode, ignoring the go.mod file in
    33  the current directory or any parent directory, if there is one. This is useful
    34  for running programs without affecting the dependencies of the main module.
    35  
    36  If the package argument doesn't have a version suffix, "go run" may run in
    37  module-aware mode or GOPATH mode, depending on the GO111MODULE environment
    38  variable and the presence of a go.mod file. See 'go help modules' for details.
    39  If module-aware mode is enabled, "go run" runs in the context of the main
    40  module.
    41  
    42  By default, 'go run' runs the compiled binary directly: 'a.out arguments...'.
    43  If the -exec flag is given, 'go run' invokes the binary using xprog:
    44  	'xprog a.out arguments...'.
    45  If the -exec flag is not given, GOOS or GOARCH is different from the system
    46  default, and a program named go_$GOOS_$GOARCH_exec can be found
    47  on the current search path, 'go run' invokes the binary using that program,
    48  for example 'go_js_wasm_exec a.out arguments...'. This allows execution of
    49  cross-compiled programs when a simulator or other execution method is
    50  available.
    51  
    52  By default, 'go run' compiles the binary without generating the information
    53  used by debuggers, to reduce build time. To include debugger information in
    54  the binary, use 'go build'.
    55  
    56  The exit status of Run is not the exit status of the compiled binary.
    57  
    58  For more about build flags, see 'go help build'.
    59  For more about specifying packages, see 'go help packages'.
    60  
    61  See also: go build.
    62  	`,
    63  }
    64  
    65  func init() {
    66  	CmdRun.Run = runRun // break init loop
    67  
    68  	work.AddBuildFlags(CmdRun, work.DefaultBuildFlags)
    69  	work.AddCoverFlags(CmdRun, nil)
    70  	CmdRun.Flag.Var((*base.StringsFlag)(&work.ExecCmd), "exec", "")
    71  }
    72  
    73  func runRun(ctx context.Context, cmd *base.Command, args []string) {
    74  	moduleLoaderState := modload.NewState()
    75  	if shouldUseOutsideModuleMode(args) {
    76  		// Set global module flags for 'go run cmd@version'.
    77  		// This must be done before modload.Init, but we need to call work.BuildInit
    78  		// before loading packages, since it affects package locations, e.g.,
    79  		// for -race and -msan.
    80  		moduleLoaderState.ForceUseModules = true
    81  		moduleLoaderState.RootMode = modload.NoRoot
    82  		modload.AllowMissingModuleImports(moduleLoaderState)
    83  		modload.Init(moduleLoaderState)
    84  	} else {
    85  		modload.InitWorkfile(moduleLoaderState)
    86  	}
    87  
    88  	work.BuildInit(moduleLoaderState)
    89  	b := work.NewBuilder("", moduleLoaderState.VendorDirOrEmpty)
    90  	defer func() {
    91  		if err := b.Close(); err != nil {
    92  			base.Fatal(err)
    93  		}
    94  	}()
    95  
    96  	i := 0
    97  	for i < len(args) && strings.HasSuffix(args[i], ".go") {
    98  		i++
    99  	}
   100  	pkgOpts := load.PackageOpts{MainOnly: true}
   101  	var p *load.Package
   102  	if i > 0 {
   103  		files := args[:i]
   104  		for _, file := range files {
   105  			if strings.HasSuffix(file, "_test.go") {
   106  				// GoFilesPackage is going to assign this to TestGoFiles.
   107  				// Reject since it won't be part of the build.
   108  				base.Fatalf("go: cannot run *_test.go files (%s)", file)
   109  			}
   110  		}
   111  		p = load.GoFilesPackage(moduleLoaderState, ctx, pkgOpts, files)
   112  	} else if len(args) > 0 && !strings.HasPrefix(args[0], "-") {
   113  		arg := args[0]
   114  		var pkgs []*load.Package
   115  		if strings.Contains(arg, "@") && !build.IsLocalImport(arg) && !filepath.IsAbs(arg) {
   116  			var err error
   117  			pkgs, err = load.PackagesAndErrorsOutsideModule(moduleLoaderState, ctx, pkgOpts, args[:1])
   118  			if err != nil {
   119  				base.Fatal(err)
   120  			}
   121  		} else {
   122  			pkgs = load.PackagesAndErrors(moduleLoaderState, ctx, pkgOpts, args[:1])
   123  		}
   124  
   125  		if len(pkgs) == 0 {
   126  			base.Fatalf("go: no packages loaded from %s", arg)
   127  		}
   128  		if len(pkgs) > 1 {
   129  			names := make([]string, 0, len(pkgs))
   130  			for _, p := range pkgs {
   131  				names = append(names, p.ImportPath)
   132  			}
   133  			base.Fatalf("go: pattern %s matches multiple packages:\n\t%s", arg, strings.Join(names, "\n\t"))
   134  		}
   135  		p = pkgs[0]
   136  		i++
   137  	} else {
   138  		base.Fatalf("go: no go files listed")
   139  	}
   140  	cmdArgs := args[i:]
   141  	load.CheckPackageErrors([]*load.Package{p})
   142  
   143  	if cfg.BuildCover {
   144  		load.PrepareForCoverageBuild(moduleLoaderState, []*load.Package{p})
   145  	}
   146  
   147  	p.Internal.OmitDebug = true
   148  	p.Target = "" // must build - not up to date
   149  	if p.Internal.CmdlineFiles {
   150  		//set executable name if go file is given as cmd-argument
   151  		var src string
   152  		if len(p.GoFiles) > 0 {
   153  			src = p.GoFiles[0]
   154  		} else if len(p.CgoFiles) > 0 {
   155  			src = p.CgoFiles[0]
   156  		} else {
   157  			// this case could only happen if the provided source uses cgo
   158  			// while cgo is disabled.
   159  			hint := ""
   160  			if !cfg.BuildContext.CgoEnabled {
   161  				hint = " (cgo is disabled)"
   162  			}
   163  			base.Fatalf("go: no suitable source files%s", hint)
   164  		}
   165  		p.Internal.ExeName = src[:len(src)-len(".go")]
   166  	} else {
   167  		p.Internal.ExeName = p.DefaultExecName()
   168  	}
   169  
   170  	a1 := b.LinkAction(moduleLoaderState, work.ModeBuild, work.ModeBuild, p)
   171  	a1.CacheExecutable = true
   172  	a := &work.Action{Mode: "go run", Actor: work.ActorFunc(buildRunProgram), Args: cmdArgs, Deps: []*work.Action{a1}}
   173  	b.Do(ctx, a)
   174  }
   175  
   176  // shouldUseOutsideModuleMode returns whether 'go run' will load packages in
   177  // module-aware mode, ignoring the go.mod file in the current directory. It
   178  // returns true if the first argument contains "@", does not begin with "-"
   179  // (resembling a flag) or end with ".go" (a file). The argument must not be a
   180  // local or absolute file path.
   181  //
   182  // These rules are slightly different than other commands. Whether or not
   183  // 'go run' uses this mode, it interprets arguments ending with ".go" as files
   184  // and uses arguments up to the last ".go" argument to comprise the package.
   185  // If there are no ".go" arguments, only the first argument is interpreted
   186  // as a package path, since there can be only one package.
   187  func shouldUseOutsideModuleMode(args []string) bool {
   188  	// NOTE: "@" not allowed in import paths, but it is allowed in non-canonical
   189  	// versions.
   190  	return len(args) > 0 &&
   191  		!strings.HasSuffix(args[0], ".go") &&
   192  		!strings.HasPrefix(args[0], "-") &&
   193  		strings.Contains(args[0], "@") &&
   194  		!build.IsLocalImport(args[0]) &&
   195  		!filepath.IsAbs(args[0])
   196  }
   197  
   198  // buildRunProgram is the action for running a binary that has already
   199  // been compiled. We ignore exit status.
   200  func buildRunProgram(b *work.Builder, ctx context.Context, a *work.Action) error {
   201  	cmdline := str.StringList(work.FindExecCmd(), a.Deps[0].BuiltTarget(), a.Args)
   202  	if cfg.BuildN || cfg.BuildX {
   203  		b.Shell(a).ShowCmd("", "%s", strings.Join(cmdline, " "))
   204  		if cfg.BuildN {
   205  			return nil
   206  		}
   207  	}
   208  
   209  	base.RunStdin(cmdline)
   210  	return nil
   211  }
   212
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