tidy.go

Documentation: cmd/go/internal/modcmd

     1  // Copyright 2018 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 mod tidy
     6  
     7  package modcmd
     8  
     9  import (
    10  	"cmd/go/internal/base"
    11  	"cmd/go/internal/cfg"
    12  	"cmd/go/internal/gover"
    13  	"cmd/go/internal/imports"
    14  	"cmd/go/internal/modload"
    15  	"cmd/go/internal/toolchain"
    16  	"context"
    17  	"fmt"
    18  
    19  	"golang.org/x/mod/modfile"
    20  )
    21  
    22  var cmdTidy = &base.Command{
    23  	UsageLine: "go mod tidy [-e] [-v] [-x] [-go=version] [-compat=version]",
    24  	Short:     "add missing and remove unused modules",
    25  	Long: `
    26  Tidy makes sure go.mod matches the source code in the module.
    27  It adds any missing modules necessary to build the current module's
    28  packages and dependencies, and it removes unused modules that
    29  don't provide any relevant packages. It also adds any missing entries
    30  to go.sum and removes any unnecessary ones.
    31  
    32  The -v flag causes tidy to print information about removed modules
    33  to standard error.
    34  
    35  The -e flag causes tidy to attempt to proceed despite errors
    36  encountered while loading packages.
    37  
    38  The -go flag causes tidy to update the 'go' directive in the go.mod
    39  file to the given version, which may change which module dependencies
    40  are retained as explicit requirements in the go.mod file.
    41  (Go versions 1.17 and higher retain more requirements in order to
    42  support lazy module loading.)
    43  
    44  The -compat flag preserves any additional checksums needed for the
    45  'go' command from the indicated major Go release to successfully load
    46  the module graph, and causes tidy to error out if that version of the
    47  'go' command would load any imported package from a different module
    48  version. By default, tidy acts as if the -compat flag were set to the
    49  version prior to the one indicated by the 'go' directive in the go.mod
    50  file.
    51  
    52  The -x flag causes tidy to print the commands download executes.
    53  
    54  See https://golang.org/ref/mod#go-mod-tidy for more about 'go mod tidy'.
    55  	`,
    56  	Run: runTidy,
    57  }
    58  
    59  var (
    60  	tidyE      bool          // if true, report errors but proceed anyway.
    61  	tidyGo     goVersionFlag // go version to write to the tidied go.mod file (toggles lazy loading)
    62  	tidyCompat goVersionFlag // go version for which the tidied go.mod and go.sum files should be “compatible”
    63  )
    64  
    65  func init() {
    66  	cmdTidy.Flag.BoolVar(&cfg.BuildV, "v", false, "")
    67  	cmdTidy.Flag.BoolVar(&cfg.BuildX, "x", false, "")
    68  	cmdTidy.Flag.BoolVar(&tidyE, "e", false, "")
    69  	cmdTidy.Flag.Var(&tidyGo, "go", "")
    70  	cmdTidy.Flag.Var(&tidyCompat, "compat", "")
    71  	base.AddChdirFlag(&cmdTidy.Flag)
    72  	base.AddModCommonFlags(&cmdTidy.Flag)
    73  }
    74  
    75  // A goVersionFlag is a flag.Value representing a supported Go version.
    76  //
    77  // (Note that the -go argument to 'go mod edit' is *not* a goVersionFlag.
    78  // It intentionally allows newer-than-supported versions as arguments.)
    79  type goVersionFlag struct {
    80  	v string
    81  }
    82  
    83  func (f *goVersionFlag) String() string { return f.v }
    84  func (f *goVersionFlag) Get() any       { return f.v }
    85  
    86  func (f *goVersionFlag) Set(s string) error {
    87  	if s != "" {
    88  		latest := gover.Local()
    89  		if !modfile.GoVersionRE.MatchString(s) {
    90  			return fmt.Errorf("expecting a Go version like %q", latest)
    91  		}
    92  		if gover.Compare(s, latest) > 0 {
    93  			return fmt.Errorf("maximum supported Go version is %s", latest)
    94  		}
    95  	}
    96  
    97  	f.v = s
    98  	return nil
    99  }
   100  
   101  func runTidy(ctx context.Context, cmd *base.Command, args []string) {
   102  	if len(args) > 0 {
   103  		base.Fatalf("go: 'go mod tidy' accepts no arguments")
   104  	}
   105  
   106  	// Tidy aims to make 'go test' reproducible for any package in 'all', so we
   107  	// need to include test dependencies. For modules that specify go 1.15 or
   108  	// earlier this is a no-op (because 'all' saturates transitive test
   109  	// dependencies).
   110  	//
   111  	// However, with lazy loading (go 1.16+) 'all' includes only the packages that
   112  	// are transitively imported by the main module, not the test dependencies of
   113  	// those packages. In order to make 'go test' reproducible for the packages
   114  	// that are in 'all' but outside of the main module, we must explicitly
   115  	// request that their test dependencies be included.
   116  	modload.ForceUseModules = true
   117  	modload.RootMode = modload.NeedRoot
   118  
   119  	goVersion := tidyGo.String()
   120  	if goVersion != "" && gover.Compare(gover.Local(), goVersion) < 0 {
   121  		toolchain.SwitchOrFatal(ctx, &gover.TooNewError{
   122  			What:      "-go flag",
   123  			GoVersion: goVersion,
   124  		})
   125  	}
   126  
   127  	modload.LoadPackages(ctx, modload.PackageOpts{
   128  		TidyGoVersion:            tidyGo.String(),
   129  		Tags:                     imports.AnyTags(),
   130  		Tidy:                     true,
   131  		TidyCompatibleVersion:    tidyCompat.String(),
   132  		VendorModulesInGOROOTSrc: true,
   133  		ResolveMissingImports:    true,
   134  		LoadTests:                true,
   135  		AllowErrors:              tidyE,
   136  		SilenceMissingStdImports: true,
   137  		Switcher:                 new(toolchain.Switcher),
   138  	}, "all")
   139  }
   140
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