Fix LT-21461: Problems with Choose Allomorph dialog box (#347)

* Fix LT-21461: Problems with Choose Allomorph dialog box

* Filter lex entries only have abstract forms

* Response to comments from Mark

Author: jtmaxwell3

Src/Common/Controls/XMLViews/MatchingObjectsBrowser.cs

@@ -1,4 +1,4 @@
-// Copyright (c) 2014-2017 SIL International
+// Copyright (c) 2014-2017 SIL International
 // This software is licensed under the LGPL, version 2.1 or later
 // (http://www.gnu.org/licenses/lgpl-2.1.html)
 
@@ -139,6 +139,16 @@ public ICmObject StartingObject
 			}
 		}
 
+		/// <summary>
+		/// Delegate for FilterResult.
+		/// </summary>
+		public delegate bool FilterResultDelegate(int hvo);
+
+		/// <summary>
+		/// Should we filter a result?
+		/// </summary>
+		public FilterResultDelegate FilterResult;
+
 		/// <summary>
 		/// Used by a Find dialog's SearchEngine to determine whether to search on a particular field or not
 		/// </summary>
@@ -384,6 +394,8 @@ private void UpdateResults(SearchField firstField, IEnumerable<int> results)
 				hvos = results.Where(hvo => StartingObject == null || StartingObject.Hvo != hvo).ToArray();
 			}
 
+			if (FilterResult != null)
+				hvos = hvos.Where(hvo => !FilterResult(hvo)).ToArray();
 			int count = hvos.Length;
 			int prevIndex = m_bvMatches.SelectedIndex;
 			int prevHvo = prevIndex == -1 ? 0 : m_bvMatches.AllItems[prevIndex];

Src/Common/FieldWorks/FieldWorks.cs

@@ -877,6 +877,12 @@ private static void EnsureDefaultCollationsPresent(LcmCache cache)
 					ws.DefaultCollation = new IcuRulesCollationDefinition("standard");
 					nullCollationWs.Append(ws.DisplayLabel + ",");
 				}
+				// Check for invalid collation here rather than in RecordSorter to avoid LT-21461 problem.
+				// This may also repair the previous if statement.
+				if (ws != null && ws.DefaultCollation != null && InvalidCollation(ws.DefaultCollation))
+				{
+					ws.DefaultCollation = new SystemCollationDefinition { LanguageTag = ws.LanguageTag };
+				}
 			}
 			if (nullCollationWs.Length > 0)
 			{
@@ -887,6 +893,17 @@ private static void EnsureDefaultCollationsPresent(LcmCache cache)
 			cache.ServiceLocator.WritingSystemManager.Save();
 		}
 
+		/// <summary>
+		/// An ICURulesCollationDefinition with empty rules was causing access violations in ICU. (LT-20268)
+		/// This method supports the band-aid fallback to SystemCollationDefinition.
+		/// </summary>
+		/// <returns>true if the CollationDefinition is invalid or is a RulesCollationDefinition with empty rules</returns>
+		private static bool InvalidCollation(CollationDefinition cd)
+		{
+			return !cd.IsValid || (cd is RulesCollationDefinition ? string.IsNullOrEmpty(((RulesCollationDefinition)cd).CollationRules) : false);
+		}
+
+
 		/// <summary>
 		/// Ensure a valid folder for LangProject.LinkedFilesRootDir.  When moving projects
 		/// between systems, the stored value may become hopelessly invalid.  See FWNX-1005

Src/LexText/LexTextControls/LinkAllomorphDlg.cs

@@ -136,6 +136,7 @@ public override void SetDlgInfo(LcmCache cache, WindowParams wp, Mediator mediat
 			base.SetDlgInfo(cache, wp, mediator, propertyTable);
 			// This is needed to make the replacement MatchingEntriesBrowser visible:
 			Controls.SetChildIndex(m_matchingObjectsBrowser, 0);
+			m_matchingObjectsBrowser.FilterResult = FilterLexEntry;
 
 			m_fwcbAllomorphs.WritingSystemFactory = cache.WritingSystemFactory;
 			m_fwcbAllomorphs.WritingSystemCode = cache.ServiceLocator.WritingSystems.DefaultVernacularWritingSystem.Handle;
@@ -150,6 +151,25 @@ public override void SetDlgInfo(LcmCache cache, WindowParams wp, Mediator mediat
 
 		#region	Other methods
 
+		/// <summary>
+		/// Filter hvo if all of its forms are abstract.
+		/// </summary>
+		private bool FilterLexEntry(int hvo)
+		{
+			ILexEntry entry = m_cache.ServiceLocator.GetObject(hvo) as ILexEntry;
+			if (entry == null)
+				return false;
+			var lf = entry.LexemeFormOA;
+			if (lf != null && !lf.IsAbstract)
+				return false;
+			foreach (var allo in entry.AlternateFormsOS)
+			{
+				if (!allo.IsAbstract)
+					return false;
+			}
+			return true;
+		}
+
 		protected override void HandleMatchingSelectionChanged()
 		{
 			if (m_selObject == null)