AddBuildFlags adds the flags common to the build, clean, get, install, list, run, and test commands.

AddCoverFlags adds coverage-related flags to "cmd".

BuildActionCoverMetaFile locates and returns the path of the meta-data file written by the "go tool cover" step as part of the build action for the "go test -cover" run action 'runAct'.

BuildInstallFunc is the action for installing a single package or executable.

FindExecCmd derives the value of ExecCmd to use.

NewBuilder returns a new Builder ready for use.

NewShell returns a new Shell.

WriteCoveragePercent writes out to the writer 'w' a "percent statements covered" for the package whose test-run action is 'runAct', based on the meta-data file 'mf'.

WriteCoverageProfile writes out a coverage profile fragment for the package whose test-run action is 'runAct'; content is written to the file 'outf' based on the coverage meta-data info found in 'mf'.

WriteCoverMetaFilesFile writes out a summary file ("meta-files file") as part of the action function for the "writeCoverMeta" pseudo action employed during "go test -coverpkg" runs where there are multiple tests and multiple packages covered.

AllowInstall returns a non-nil error if this invocation of the go command is allowed to install a.Target.

ExecCmd is the command to use to run user binaries.

Tests can override this by setting $TESTGO_TOOLCHAIN_VERSION.

VetExplicit records whether the vet flags were set explicitly on the command line.

VetFlags are the default flags to pass to vet.

VetTool is the path to an alternate vet tool binary.

An Action represents a single action in the action graph.

A Builder holds global state about a build.

A Shell runs shell commands and performs shell-like file system operations.

An Actor runs an action.

An ActorFunc is an Actor that calls the function.

BuildMode specifies the build mode: are we just building things or also installing the results?.