//
// Lookup should only be used with non-factored verbs
// such as "go" and "toolchain", usually to find versions
// or version-like strings.
func GoModLookup(gomod []byte, key string) string {
	for len(gomod) > 0 {
		var line []byte
		line, gomod, _ = bytes.Cut(gomod, nl)
		line = bytes.TrimSpace(line)
		if v, ok := parseKey(line, key); ok {
			return v
		}
	}
	return ""
}

---
version: 2
updates:
  - package-ecosystem: gomod
    directory: /
    schedule:
      interval: weekly
  - package-ecosystem: github-actions
    directory: /
    schedule:
      interval: weekly
  - package-ecosystem: gomod
    directory: /tests
    schedule:

env TESTGO_VERSION=go1.500
env TESTGO_VERSION_SWITCH=mismatch

# go env GOMOD should not trigger a toolchain download
cd $GOPATH/mod
go env GOMOD
stdout mod[/\\]go.mod
! stderr 'go: toolchain go1.500 invoked to provide go1.700'

# go env GOWORK should not trigger a toolchain download
cd $GOPATH/work
go env GOWORK
stdout work[/\\]go.work
! stderr 'go: toolchain go1.500 invoked to provide go1.700'

-- $GOPATH/mod/go.mod --

-- go.mod --
module quoter

require rsc.io/quote/v3 v3.0.0

-- main.go --
package main

import (
	"fmt"

go mod init example.com/m
grep example.com/m go.alt.mod

# 'go env GOMOD' should print the path to the real file.
# 'go env' does not recognize the '-modfile' flag.
go env GOMOD
stdout '^'$WORK${/}gopath${/}src${/}'go\.mod$'

# 'go list -m' should print the effective go.mod file as GoMod though.
go list -m -f '{{.GoMod}}'
stdout '^go.alt.mod$'

# go mod edit should operate on the alternate file

# list {{.Dir}} shows replaced directories
cp go.mod2 go.mod
go list -mod=mod -f {{.Dir}} rsc.io/quote
go list -m -f '{{.Path}} {{.Version}} {{.Dir}}{{with .Replace}} {{.GoMod}} => {{.Version}} {{.Dir}} {{.GoMod}}{{end}}' all
stdout 'mod[\\/]rsc.io[\\/]quote@v1.5.1'
stdout 'v1.3.0.*mod[\\/]rsc.io[\\/]sampler@v1.3.1 .*[\\/]v1.3.1.mod => v1.3.1.*sampler@v1.3.1 .*[\\/]v1.3.1.mod'

# list std should work
go list std

cd ../4-to-1
go list -m gopkg.in/src-d/go-git.v4

cd ../4-to-incompatible
go list -m gopkg.in/src-d/go-git.v4

# A mismatched gopkg.in path should not be able to replace a different major version.
cd ../3-to-gomod-4
! go list -m gopkg.in/src-d/go-git.v3

# ensure that 'direct' mode can resolve the package to the module.
# For a while, (*modfetch.codeRepo).Stat was not checking for a go.mod file,
# which would produce a hard error at the subsequent call to GoMod.

go get -v

-- go.mod --
module example.com
go 1.13

-- main.go --
package main

import _ "vcs-test.golang.org/git/v3pkg.git/v3"

func findCodeRoots() []Dir {
	var list []Dir
	if !testGOPATH {
		// Check for use of modules by 'go env GOMOD',
		// which reports a go.mod file path if modules are enabled.
		stdout, _ := exec.Command(goCmd(), "env", "GOMOD").Output()
		gomod := string(bytes.TrimSpace(stdout))

		usingModules = len(gomod) > 0
		if usingModules && buildCtx.GOROOT != "" {
			list = append(list,

stderr 'chdir.*nonexist'

# check for -C in subcommands with custom flag parsing
# cmd/go/chdir_test.go handles the normal ones more directly.

# go doc
go doc -C ../strings HasPrefix

# go env
go env -C $OLD/custom GOMOD
stdout 'custom[\\/]go.mod'
! go env -C ../nonexist
stderr '^go: chdir ../nonexist: '

# go test
go test -C ../strings -n
stderr 'strings\.test'

# go vet
go vet -C ../strings -n
stderr strings_test