if err == nil {
				err = modfetch.WriteGoSum(ctx, keepSums(ctx, loaded, requirements, addBuildListZipSums), mustHaveCompleteRequirements())
			}
		}
	}()

	// Make a best-effort attempt to acquire the side lock, only to exclude
	// previous versions of the 'go' command from making simultaneous edits.
	if unlock, err := modfetch.SideLock(ctx); err == nil {
		defer unlock()
	}

// This should be called before starting the push, from the thread creating
// the push context.
func (ps *PushContext) InitContext(env *Environment, oldPushContext *PushContext, pushReq *PushRequest) error {
	// Acquire a lock to ensure we don't concurrently initialize the same PushContext.
	// If this does happen, one thread will block then exit early from InitDone=true
	ps.initializeMutex.Lock()
	defer ps.initializeMutex.Unlock()

)

// netTestSem is a semaphore limiting the number of tests that may use the
// external network in parallel. If non-nil, it contains one buffer slot per
// test (send to acquire), with a low enough limit that the overall number of
// connections (summed across subprocesses) stays at or below base.NetLimit.
var netTestSem chan struct{}

var exeSuffix string = func() string {

			tooOld := !oldTime.IsZero() && pconn.idleAt.Round(0).Before(oldTime)
			if tooOld {
				// Async cleanup. Launch in its own goroutine (as if a
				// time.AfterFunc called it); it acquires idleMu, which we're
				// holding, and does a synchronous net.Conn.Close.
				go pconn.closeConnIfStillIdle()
			}
			if pconn.isBroken() || tooOld {
				// If either persistConn.readLoop has marked the connection