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