Ignore RuntimeError when moving in word. (PR #7133)

Pressing end while in browse mode of an empty Microsoft Word document no longer causes a runtime error.

Fix for #7009

source/NVDAObjects/window/winword.py

@@ -833,7 +833,11 @@ def collapse(self,end=False):
 		if end:
 			oldEndOffset=self._rangeObj.end
 		self._rangeObj.collapse(wdCollapseEnd if end else wdCollapseStart)
-		if end and self._rangeObj.end<oldEndOffset:
+		newEndOffset = self._rangeObj.end
+		# the new endOffset should not have become smaller than the old endOffset, this could cause an infinite loop in
+		# a case where you called move end then collapse until the size of the range is no longer being reduced.
+		# For an example of this see sayAll (specifically readTextHelper_generator in sayAllHandler.py)
+		if end and newEndOffset < oldEndOffset :
 			raise RuntimeError
 
 	def copy(self):

source/cursorManager.py

@@ -115,8 +115,15 @@ def _caretMovementScriptHelper(self,gesture,unit,direction=None,posConstant=text
 		if not self._lastSelectionMovedStart and not oldInfo.isCollapsed:
 			info.move(textInfos.UNIT_CHARACTER,-1)
 		if posUnit is not None:
+			# expand and collapse to ensure that we are aligned with the end of the intended unit
 			info.expand(posUnit)
-			info.collapse(end=posUnitEnd)
+			try:
+				info.collapse(end=posUnitEnd)
+			except RuntimeError:
+				# MS Word has a "virtual linefeed" at the end of the document which can cause RuntimeError to be raised.
+				# In this case it can be ignored.
+				# See #7009
+				pass
 			if posUnitEnd:
 				info.move(textInfos.UNIT_CHARACTER,-1)
 		if direction is not None:

source/sayAllHandler.py

@@ -131,6 +131,7 @@ def readTextHelper_generator(cursor):
 					try:
 						reader.collapse(end=True)
 					except RuntimeError: #MS Word when range covers end of document
+						# Word specific: without this exception to indicate that further collapsing is not posible, say-all could enter an infinite loop.
 						speech.speakWithoutPauses(None)
 						keepReading=False
 			else: