go/src/cmd/go/internal/toolchain/select.go

const gotoolchainModule …

const gotoolchainVersion …

const targetEnv …

const countEnv …

const maxSwitch …

// FilterEnv returns a copy of env with internal GOTOOLCHAIN environment
// variables filtered out.
func FilterEnv(env []string) []string { … }

var counterErrorsInvalidToolchainInFile …

var toolchainTrace …

// Select invokes a different Go toolchain if directed by
// the GOTOOLCHAIN environment variable or the user's configuration
// or go.mod file.
// It must be called early in startup.
// See https://go.dev/doc/toolchain#select.
func Select() { … }

var counterSelectExec …

var TestVersionSwitch …

// Exec invokes the specified Go toolchain or else prints an error and exits the process.
// If $GOTOOLCHAIN is set to path or min+path, Exec only considers the PATH
// as a source of Go toolchains. Otherwise Exec tries the PATH but then downloads
// a toolchain if necessary.
func Exec(gotoolchain string) { … }

func size(path string) int64 { … }

var writeBits …

// raceSafeCopy copies the file old to the file new, being careful to ensure
// that if multiple go commands call raceSafeCopy(old, new) at the same time,
// they don't interfere with each other: both will succeed and return and
// later observe the correct content in new. Like in the build cache, we arrange
// this by opening new without truncation and then writing the content.
// Both go commands can do this simultaneously and will write the same thing
// (old never changes content).
func raceSafeCopy(old, new string) error { … }

// modGoToolchain finds the enclosing go.work or go.mod file
// and returns the go version and toolchain lines from the file.
// The toolchain line overrides the version line
func modGoToolchain() (file, goVers, toolchain string) { … }

// goInstallVersion reports whether the command line is go install m@v or go run m@v.
// If so, Select must not read the go.mod or go.work file in "auto" or "path" mode.
func goInstallVersion() bool { … }