[[sec:partial-rewrite]]
==== Partial rewrite of existing content

A "complete rewrite" causes all existing content to be discarded, thereby losing any changes made directly in the IDE. The `beforeMerged` hook makes it possible to overwrite just certain parts of the existing content. The following example removes all existing dependencies from the `Module` domain object:

 * the configuration cache, so that its outputs in turn become fixed. The node can then be discarded from the graph and replaced with its (now fixed) outputs.</p>
 */
public interface ProviderInternal<T> extends Provider<T>, ValueSupplier, TaskDependencyContainer, EvaluationContext.EvaluationOwner {
    /**

    }

    /**
     * Is this node ready to execute or discard (eg because a dependency has failed)?
     */
    public boolean allDependenciesComplete() {
        return state == ExecutionState.SHOULD_RUN && dependenciesState != DependenciesState.NOT_COMPLETE;
    }

    /**
     * Can this node execute or should it be discarded? Should only be called when {@link #allDependenciesComplete()} returns true.
     */

The property getter method must be `public` or `protected`. The method can be `abstract` or, in cases where this isn't possible, can have a dummy method body.
The method body is discarded.

Here is an example that shows a task type that receives a two services via property getter methods:

====
[source.multi-language-sample,java]
.Download.java
----

	// at least one buffer of work and reduces contention on the
	// global work lists.
	//
	// wbuf1 is always the buffer we're currently pushing to and
	// popping from and wbuf2 is the buffer that will be discarded
	// next.
	//
	// Invariant: Both wbuf1 and wbuf2 are nil or neither are.
	wbuf1, wbuf2 *workbuf

	// Bytes marked (blackened) on this gcWork. This is aggregated
	// into work.bytesMarked by dispose.

[[sec:partial-overwrite]]
==== Partial overwrite of existing content

// additional pages after the segment end.
// The function returns a slice of pointers to the headers in the input
// slice, which are valid only while phdrs is not modified or discarded.
func ProgramHeadersForMapping(phdrs []elf.ProgHeader, mapOff, mapSz uint64) []*elf.ProgHeader {
	const (
		// pageSize defines the virtual memory page size used by the loader. This

	// Wait for messages to be sent...
	h.wg.Wait()

	// Set logch to nil and close it.
	// This will block all Send operations,
	// and finish the existing ones.
	// All future ones will be discarded.
	h.logChMu.Lock()
	xioutil.SafeClose(h.logCh)
	h.logCh = nil
	h.logChMu.Unlock()

	ovfl  error // error message for overflow/underflow (for arrays, of the elements)
}

// ignoreUint discards a uint value with no destination.
func ignoreUint(i *decInstr, state *decoderState, v reflect.Value) {
	state.decodeUint()
}

// ignoreTwoUints discards a uint value with no destination. It's used to skip
// complex values.
func ignoreTwoUints(i *decInstr, state *decoderState, v reflect.Value) {

//
// To unmarshal a JSON array into a Go array, Unmarshal decodes
// JSON array elements into corresponding Go array elements.
// If the Go array is smaller than the JSON array,
// the additional JSON array elements are discarded.
// If the JSON array is smaller than the Go array,
// the additional Go array elements are set to zero values.
//
// To unmarshal a JSON object into a map, Unmarshal first establishes a map to