"internal/goexperiment"
)

// Default returns the default cache to use.
// It never returns nil.
func Default() Cache {
	defaultOnce.Do(initDefaultCache)
	return defaultCache
}

var (
	defaultOnce  sync.Once
	defaultCache Cache
)

// cacheREADME is a message stored in a README in the cache directory.
// Because the cache lives outside the normal Go trees, we leave the
// README as a courtesy to explain where it came from.

// Package par implements parallel execution helpers.
package par

import (
	"errors"
	"math/rand"
	"sync"
	"sync/atomic"
)

// Work manages a set of work items to be executed in parallel, at most once each.
// The items in the set must all be valid map keys.
type Work[T comparable] struct {
	f       func(T) // function to run for each item
	running int     // total number of runners

	mu      sync.Mutex

"""
        file("in.txt").text = "in"

        when:
        run("merge")

        then:
        output.count("calculating value") == 2 // once for task dependency calculation, once for task execution
    }

    def "task @InputFiles file collection provider is called once only when task executes"() {
        taskTypeWithInputFileCollection()
        buildFile """
            task merge(type: InputFilesTask) {

 *
 * <ul>
 *     <li>All builds in the tree use the root build's cache configuration, once that configuration is available (ie the root build's settings have been evaluated).</li>
 *     <li>If caching is required in non-root build before the root build's configuration is available, that build's own cache configuration will be used.
 *      Once the root build's configuration is available, the build-specific configuration is discarded.
 *     </li>

        "network interceptor ${interceptors[index - 1]} must retain the same host and port"
      }
      check(calls == 1) {
        "network interceptor ${interceptors[index - 1]} must call proceed() exactly once"
      }
    }

    // Call the next interceptor in the chain.
    val next = copy(index = index + 1, request = request)
    val interceptor = interceptors[index]

    @Suppress("USELESS_ELVIS")

       *
       * - after the requireNonNull call below. (And this object has its Runnable.run override
       *   called only once, just as it has its Executor.execute override called only once.)
       *
       * - if we return immediately from `execute` (in which case we never get here)
       *

       *
       * - after the requireNonNull call below. (And this object has its Runnable.run override
       *   called only once, just as it has its Executor.execute override called only once.)
       *
       * - if we return immediately from `execute` (in which case we never get here)
       *

	// We start ServeHTTP in a goroutine, which may take a long
	// time if the file is large. The newPopulateResponseWriter
	// call returns a channel which either ServeHTTP or finish()
	// sends our *Response on, once the *Response itself has been
	// populated (even if the body itself is still being
	// written to the res.Body, a pipe)
	rw, resc := newPopulateResponseWriter()
	go func() {
		t.fh.ServeHTTP(rw, req)
		rw.finish()

        val generatedTopLevelClassifiers = declarationGenerators
            .asSequence()
            .flatMap {
                // FIXME this function should be called only once during plugin's lifetime, so this usage is not really correct (2)
                it.getTopLevelClassIds()
            }
            .filter { it.packageFqName == packageFqName }
            .map { it.shortClassName }

	return syscall.Exec(argv0, os.Args, os.Environ())
}

// freezeServices will freeze all incoming S3 API calls.
// For each call, unfreezeServices must be called once.
func freezeServices() {
	// Use atomics for globalServiceFreeze, so we can read without locking.
	// We need a lock since we are need the 2 atomic values to remain in sync.
	globalServiceFreezeMu.Lock()