Fix LT-21585: Hermit Crab Parsing Error yellow box crash

Src/GenerateHCConfig/ConsoleLogger.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.ComponentModel;
 using SIL.LCModel;
 using SIL.FieldWorks.WordWorks.Parser;
@@ -103,5 +103,10 @@ public void InvalidReduplicationForm(IMoForm form, string reason, IMoMorphSynAna
 		{
 			Console.WriteLine("The reduplication form \"{0}\" is invalid. Reason: {1}", form.Form.VernacularDefaultWritingSystem.Text, reason);
 		}
+
+		public void InvalidRewriteRule(IPhRegularRule rule, string reason)
+		{
+			Console.WriteLine("The rewrite rule \"{0}\" is invalid. Reason: {1}", rule.Name.BestAnalysisVernacularAlternative.Text, reason);
+		}
 	}
 }

Src/LexText/ParserCore/HCLoader.cs

@@ -236,6 +236,8 @@ private void LoadLanguage()
 						if (regRule.StrucDescOS.Count > 0 || regRule.RightHandSidesOS.Any(rhs => rhs.StrucChangeOS.Count > 0))
 						{
 							RewriteRule hcRegRule = LoadRewriteRule(regRule);
+							if (hcRegRule == null)
+								continue;
 							m_morphophonemic.PhonologicalRules.Add(hcRegRule);
 							if (!m_notOnClitics)
 								m_clitic.PhonologicalRules.Add(hcRegRule);
@@ -1698,6 +1700,11 @@ private RewriteRule LoadRewriteRule(IPhRegularRule prule)
 			}
 			hcPrule.Properties[HCParser.PRuleID] = prule.Hvo;
 
+			if (hcPrule.Lhs.Children.Count > 1)
+			{
+				m_logger.InvalidRewriteRule(prule, ParserCoreStrings.ksMaxElementsInRule);
+				return null;
+			}
 			foreach (IPhSegRuleRHS rhs in prule.RightHandSidesOS)
 			{
 				var psubrule = new RewriteSubrule();
@@ -1748,6 +1755,12 @@ private RewriteRule LoadRewriteRule(IPhRegularRule prule)
 					psubrule.RightEnvironment = rightPattern;
 				}
 
+				if (psubrule.Rhs.Children.Count > 1)
+				{
+					m_logger.InvalidRewriteRule(prule, ParserCoreStrings.ksMaxElementsInRule);
+					return null;
+				}
+
 				hcPrule.Subrules.Add(psubrule);
 			}
 

Src/LexText/ParserCore/HCParser.cs

@@ -641,6 +641,14 @@ public void InvalidReduplicationForm(IMoForm form, string reason, IMoMorphSynAna
 				m_xmlWriter.WriteElementString("Reason", reason);
 				m_xmlWriter.WriteEndElement();
 			}
+			public void InvalidRewriteRule(IPhRegularRule rule, string reason)
+			{
+				m_xmlWriter.WriteStartElement("LoadError");
+				m_xmlWriter.WriteAttributeString("type", "invalid-rewrite-rule");
+				m_xmlWriter.WriteElementString("Rule", rule.Name.BestAnalysisVernacularAlternative.Text);
+				m_xmlWriter.WriteElementString("Reason", reason);
+				m_xmlWriter.WriteEndElement();
+			}
 		}
 	}
 }

Src/LexText/ParserCore/IHCLoadErrorLogger.cs

@@ -1,4 +1,4 @@
-using SIL.LCModel;
+using SIL.LCModel;
 
 namespace SIL.FieldWorks.WordWorks.Parser
 {
@@ -10,5 +10,6 @@ public interface IHCLoadErrorLogger
 		void DuplicateGrapheme(IPhPhoneme phoneme);
 		void InvalidEnvironment(IMoForm form, IPhEnvironment env, string reason, IMoMorphSynAnalysis msa);
 		void InvalidReduplicationForm(IMoForm form, string reason, IMoMorphSynAnalysis msa);
+		void InvalidRewriteRule(IPhRegularRule prule, string reason);
 	}
 }

Src/LexText/ParserCore/ParserCoreStrings.resx

@@ -189,4 +189,7 @@
   <data name="ksTestX" xml:space="preserve">
     <value>Tested {0}</value>
   </data>
+  <data name="ksMaxElementsInRule" xml:space="preserve">
+    <value>A rule can't have more than one element in its left-hand side or its right-hand side.</value>
+  </data>
 </root>

Src/LexText/ParserCore/ParserCoreTests/HCLoaderTests.cs

@@ -41,7 +41,8 @@ private enum LoadErrorType
 			InvalidPhoneme,
 			DuplicateGrapheme,
 			InvalidEnvironment,
-			InvalidRedupForm
+			InvalidRedupForm,
+			InvalidRewriteRule
 		}
 
 		private class TestHCLoadErrorLogger : IHCLoadErrorLogger
@@ -82,6 +83,11 @@ public void InvalidReduplicationForm(IMoForm form, string reason, IMoMorphSynAna
 			{
 				m_loadErrors.Add(Tuple.Create(LoadErrorType.InvalidRedupForm, (ICmObject) msa));
 			}
+
+			public void InvalidRewriteRule(IPhRegularRule rule, string reason)
+			{
+				m_loadErrors.Add(Tuple.Create(LoadErrorType.InvalidRedupForm, (ICmObject) rule));
+			}
 		}
 
 		private readonly List<Tuple<LoadErrorType, ICmObject>> m_loadErrors = new List<Tuple<LoadErrorType, ICmObject>>();
@@ -988,9 +994,6 @@ public void PhonologicalRule()
 			Cache.LanguageProject.PhonologicalDataOA.PhonRulesOS.Add(prule);
 			prule.Name.SetAnalysisDefaultWritingSystem("prule");
 			prule.Direction = 2;
-			IPhSimpleContextSeg segCtxt = Cache.ServiceLocator.GetInstance<IPhSimpleContextSegFactory>().Create();
-			prule.StrucDescOS.Add(segCtxt);
-			segCtxt.FeatureStructureRA = GetPhoneme("a");
 			IPhSimpleContextNC ncCtxt = Cache.ServiceLocator.GetInstance<IPhSimpleContextNCFactory>().Create();
 			prule.StrucDescOS.Add(ncCtxt);
 			ncCtxt.FeatureStructureRA = m_vowel;
@@ -1021,7 +1024,7 @@ public void PhonologicalRule()
 
 			Assert.That(hcPrule.Direction, Is.EqualTo(Machine.DataStructures.Direction.LeftToRight));
 			Assert.That(hcPrule.ApplicationMode, Is.EqualTo(RewriteApplicationMode.Simultaneous));
-			Assert.That(hcPrule.Lhs.ToString(), Is.EqualTo(m_lang.Strata[0].CharacterDefinitionTable["a"].FeatureStruct + VowelFS));
+			Assert.That(hcPrule.Lhs.ToString(), Is.EqualTo(VowelFS));
 
 			Assert.That(hcPrule.Subrules.Count, Is.EqualTo(1));
 			RewriteSubrule subrule = hcPrule.Subrules[0];

Src/Transforms/Presentation/FormatCommon.xsl

@@ -118,6 +118,15 @@
 										</span>
 									</li>
 								</xsl:when>
+								<xsl:when test="@type = 'invalid-rewrite-rule'">
+									<li>
+										<xsl:text>The rewrite rule "</xsl:text>
+										<xsl:value-of select="Rule" />
+										<xsl:text>" is invalid. Reason: </xsl:text>
+										<xsl:value-of select="Reason" />
+										<xsl:text> </xsl:text>
+									</li>
+								</xsl:when>
 								<xsl:otherwise>
 									<!-- Do not expect any others to happen, but just in case, we show them in all their HC glory -->
 									<li><xsl:value-of select="."/></li>