There are also some constraints and possible limitations.

[[sec:constrained_syntax]]
==== Constrained Syntax

The `plugins {}` block does not support arbitrary code.

It is constrained to be idempotent (produce the same result every time) and side effect-free (safe for Gradle to execute at any time).

The form is:

====
[.multi-language-sample]
=====
.build.gradle.kts
[source,kotlin]
----

			req:  &Request{Method: "POST", Header: Header{"Idempotency-Key": {"x"}}},
			want: true,
		},
		{
			name: "POST_x-idempotency-key",
			req:  &Request{Method: "POST", Header: Header{"X-Idempotency-Key": {"x"}}},
			want: true,
		},
		{
			name: "POST_body",
			req:  &Request{Method: "POST", Header: Header{"Idempotency-Key": {"x"}}, Body: someBody},
			want: false,
		},
	}

	// thread B and did not need to execute the syscall, but did anyway
	// because doAllThreadsSyscall could not be sure whether it was
	// required.
	//
	// Some system calls may not be idempotent, so we ensure each thread
	// executes the system call exactly once.
	for mp := allm; mp != nil; mp = mp.alllink {
		for atomic.Load64(&mp.procid) == 0 {
			// Thread is starting.
			osyield()
		}
	}

	// Unreserve is called by the scheduling framework when a reserved pod was
	// rejected, an error occurred during reservation of subsequent plugins, or
	// in a later phase. The Unreserve method implementation must be idempotent
	// and may be called by the scheduler even if the corresponding Reserve
	// method for the same plugin was not called.
	Unreserve(ctx context.Context, state *CycleState, p *v1.Pod, nodeName string)
}

// mounting, or unmounting a volume that are executed with a NewNestedPendingOperations which
// prevents more than one operation from being triggered on the same volume.
//
// These operations should be idempotent (for example, AttachVolume should
// still succeed if the volume is already attached to the node, etc.). However,
// they depend on the volume plugins to implement this behavior.
//

	return s.muxAndDiscoveryCompleteSignals
}

// RegisterDestroyFunc registers a function that will be called during Destroy().
// The function have to be idempotent and prepared to be called more than once.
func (s *GenericAPIServer) RegisterDestroyFunc(destroyFn func()) {
	s.destroyFns = append(s.destroyFns, destroyFn)
}

}

// Close - calls the cleanup actions in reverse order
func (g *GetObjectReader) Close() error {
	if g == nil {
		return nil
	}
	// sync.Once is used here to ensure that Close() is
	// idempotent.
	g.once.Do(func() {
		for i := len(g.cleanUpFns) - 1; i >= 0; i-- {
			g.cleanUpFns[i]()
		}
	})
	return nil
}

// compressionIndexEncrypter returns a function that will read data from input,

	// summaries.
	p.update(base, size/pageSize, true, false)
}

// enableChunkHugePages enables huge pages for the chunk bitmap mappings (disabled by default).
//
// This function is idempotent.
//
// A note on latency: for sufficiently small heaps (<10s of GiB) this function will take constant
// time, but may take time proportional to the size of the mapped heap beyond that.
//

	defer r.customStorageLock.Unlock()

	storageMap := r.customStorage.Load().(crdStorageMap)
	for _, crdInfo := range storageMap {
		for _, storage := range crdInfo.storages {
			// DestroyFunc have to be implemented in idempotent way,
			// so the potential race with r.tearDown() (being called
			// from a goroutine) is safe.
			storage.CustomResource.DestroyFunc()
		}
	}
}

evaluation.\n\nIfNeeded: the webhook will be called at least one additional time as part of the admission evaluation if the object being admitted is modified by other admission plugins after the initial webhook call. Webhooks that specify this option *must* be idempotent, able to process objects they previously admitted. Note: * the number of additional invocations is not guaranteed to be exactly one. * if additional invocations result in further modifications to the object, webhooks are not guaranteed to be invoked...