Fix issue processwire/processwire-issues#653 Inputfield parent issue causing out of memory errors when two buttons lacking name attributes

wire/core/Inputfield.php

@@ -493,12 +493,31 @@ abstract class Inputfield extends WireData implements Module {
 	 */
 	public function setParent(InputfieldWrapper $parent) {
 		if($this->parent && $this->parent instanceof InputfieldWrapper && $this->parent !== $parent) {
-			$this->parent->remove($this);
+			$oldRootParent = $this->getRootParent();
+			if(!$oldRootParent) $oldRootParent = $this->parent;
+			$newRootParent = $parent->getRootParent();
+			if(!$newRootParent) $newRootParent = $parent;
+			if($oldRootParent === $newRootParent) {
+				// if field staying in the same form, remove from previous parent
+				$this->parent->remove($this);
+			}
 		}
 		$this->parent = $parent; 
 		return $this; 
 	}
 
+	/**
+	 * Unset any previously set parent
+	 * 
+	 * #pw-internal
+	 * @return $this
+	 * 
+	 */
+	public function unsetParent() {
+		$this->parent = null;
+		return $this;
+	}
+
 	/**
 	 * Get this Inputfield’s parent InputfieldWrapper, or NULL if it doesn’t have one.
 	 * 

wire/core/InputfieldWrapper.php

@@ -416,6 +416,7 @@ class InputfieldWrapper extends Inputfield implements \Countable, \IteratorAggre
 				array_push($wrappers, $inputfield); 
 			} 
 
+			$inputfield->unsetParent();
 			$wrapper->add($inputfield); 
 		}