if d > 0 && d < bestDepth {
					best = path
					bestDepth = d
				}
			}
			why := modload.Why(best)
			if why == "" {
				vendoring := ""
				if *whyVendor {
					vendoring = " to vendor"
				}
				why = "(main module does not need" + vendoring + " module " + m.Path + ")\n"
			}
			fmt.Printf("%s# %s\n%s", sep, m.Path, why)
			sep = "\n"
		}
	} else {
		// Resolve to packages.

-- modules.txt.required_but_not_explicit --
## workspace
# example.com/p v1.0.0 => ./p
## go 1.21
# example.com/q v1.0.0 => ./q
## explicit; go 1.21
-- required_but_not_explicit_error.txt --
go: inconsistent vendoring in $GOPATH${/}src:
	example.com/p@v1.0.0: is explicitly required in go.mod, but not marked as explicit in vendor/modules.txt

	To ignore the vendor directory, use -mod=readonly or -mod=mod.
	To sync the vendor directory, run:

cp go.mod go.mod.orig

# For modules whose go.mod file does not include a 'go' directive,
# we assume the language and dependency semantics of Go 1.16,
# but do not trigger “automatic vendoring” mode (-mod=vendor),
# which was added in Go 1.14 and was not triggered
# under the same conditions in Go 1.16 (which would instead
# default to -mod=readonly when no 'go' directive is present).

# For Go 1.16 modules, 'all' should prune out dependencies of tests,

env GO111MODULE=on

# Replacement should not use a vendor directory as the target.
! go mod vendor
stderr 'replacement path ./vendor/not-rsc.io/quote/v3 inside vendor directory'

cp go.mod1 go.mod
rm -r vendor

# Before vendoring, we expect to see the original directory.
go list -f '{{with .Module}}{{.Version}}{{end}} {{.Dir}}' rsc.io/quote/v3
stdout 'v3.0.0'
stdout '.*[/\\]not-rsc.io[/\\]quote[/\\]v3'

# In GOPATH mode, module legacy support does path rewriting very similar to vendoring.

env GO111MODULE=off

go list -f '{{range .Imports}}{{.}}{{"\n"}}{{end}}' old/p1
stdout ^new/p1$

go list -f '{{range .Imports}}{{.}}{{"\n"}}{{end}}' new/p1
stdout ^new/p2$           # not new/v2/p2
! stdout ^new/v2
stdout ^new/sub/x/v1/y$   # not new/sub/v2/x/v1/y
! stdout ^new/sub/v2
stdout ^new/sub/inner/x # not new/sub/v2/inner/x

go build old/p1 new/p1

# A 'go 1.13' vendor/modules.txt file is not usually sufficient
# to pass those checks.
go mod edit -go=1.14

! go list -f {{.Dir}} -tags tools all
stderr '^go: inconsistent vendoring in '$WORK[/\\]auto':$'
stderr '^\texample.com/printversion@v1.0.0: is explicitly required in go.mod, but not marked as explicit in vendor/modules.txt'

type gcimports struct {
	fset     *token.FileSet
	packages map[string]*types.Package
	lookup   Lookup
}

func (m *gcimports) Import(path string) (*types.Package, error) {
	return m.ImportFrom(path, "" /* no vendoring */, 0)
}

func (m *gcimports) ImportFrom(path, srcDir string, mode types.ImportMode) (*types.Package, error) {
	if mode != 0 {
		panic("mode must be 0")
	}

must not already exist.

Init accepts one optional argument, the module path for the new module. If the
module path argument is omitted, init will attempt to infer the module path
using import comments in .go files, vendoring tool configuration files (like
Gopkg.lock), and the current directory (if in GOPATH).

See https://golang.org/ref/mod#go-mod-init for more about 'go mod init'.
`,
	Run: runInit,
}

func init() {

# This test exercises that vendoring works properly using the workspace in the
# the work_prune test case.

go work vendor
cmp vendor/modules.txt modules.txt.want
cmp vendor/example.com/b/b.go b/b.go
cmp vendor/example.com/q/q.go q1_1_0/q.go
go list -m -f '{{.Version}}' example.com/q
stdout '^v1.1.0$'

go list -f '{{.Dir}}' example.com/q
stdout $GOPATH[\\/]src[\\/]vendor[\\/]example.com[\\/]q
go list -f '{{.Dir}}' example.com/b

env GO111MODULE=on

# Without vendoring, a build should succeed unless -mod=vendor is set.
[!short] go build
[!short] ! go build -mod=vendor

# Without vendoring, 'go list' should report the replacement directory for
# a package in a replaced module.
go list -f {{.Dir}} x
stdout 'src[\\/]x'

# 'go mod vendor' should copy all replaced modules to the vendor directory.
go mod vendor -v
stderr '^# x v1.0.0 => ./x'
stderr '^x'