Fix USFM parsing bugs

src/SIL.Machine/Corpora/ScriptureRefUsfmParserHandlerBase.cs

@@ -53,7 +53,7 @@ public override void Verse(
             string pubNumber
         )
         {
-            if (state.VerseRef.Equals(_curVerseRef))
+            if (state.VerseRef.Equals(_curVerseRef) && !_duplicateVerse)
             {
                 EndVerseText(state, CreateVerseRefs());
                 // ignore duplicate verses

src/SIL.Machine/Corpora/UsfmParser.cs

@@ -1,5 +1,7 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Linq;
+using System.Text;
 using System.Text.RegularExpressions;
 using SIL.Scripture;
 
@@ -41,7 +43,19 @@ public static void Parse(
                 versification,
                 preserveWhitespace
             );
-            parser.ProcessTokens();
+            try
+            {
+                parser.ProcessTokens();
+            }
+            catch (Exception ex)
+            {
+                var sb = new StringBuilder();
+                sb.Append(
+                    $"An error occurred while parsing the USFM text in Verse: {parser.State.VerseRef}, line: {parser.State.LineNumber}, "
+                );
+                sb.Append($"column: {parser.State.ColumnNumber}, error: '{ex.Message}'");
+                throw new InvalidOperationException(sb.ToString(), ex);
+            }
         }
 
         private static readonly Regex OptBreakSplitter = new Regex("(//)", RegexOptions.Compiled);

src/SIL.Machine/Corpora/UsfmTextUpdater.cs

@@ -361,7 +361,7 @@ private void SkipTokens(UsfmParserState state)
         private bool ReplaceWithNewTokens(UsfmParserState state)
         {
             bool newText = _replace.Count > 0 && _replace.Peek();
-            int tokenEnd = state.Index + state.SpecialTokenCount + 1;
+            int tokenEnd = state.Index + state.SpecialTokenCount;
             bool existingText = false;
             for (int index = _tokenIndex; index <= tokenEnd; index++)
             {

tests/SIL.Machine.Tests/Corpora/UsfmMemoryTextTests.cs

@@ -25,8 +25,16 @@ public void GetRows_VerseDescriptiveTitle()
         {
             Assert.That(rows, Has.Length.EqualTo(1));
 
-            Assert.That(rows[0].Ref, Is.EqualTo(ScriptureRef.Parse("MAT 1:1")));
-            Assert.That(rows[0].Text, Is.EqualTo("Descriptive title"));
+            Assert.That(
+                rows[0].Ref,
+                Is.EqualTo(ScriptureRef.Parse("MAT 1:1")),
+                string.Join(",", rows.ToList().Select(tr => tr.Ref.ToString()))
+            );
+            Assert.That(
+                rows[0].Text,
+                Is.EqualTo("Descriptive title"),
+                string.Join(",", rows.ToList().Select(tr => tr.Text))
+            );
         });
     }
 
@@ -44,8 +52,16 @@ public void GetRows_LastSegment()
         {
             Assert.That(rows, Has.Length.EqualTo(1));
 
-            Assert.That(rows[0].Ref, Is.EqualTo(ScriptureRef.Parse("MAT 1:1")));
-            Assert.That(rows[0].Text, Is.EqualTo("Last segment"));
+            Assert.That(
+                rows[0].Ref,
+                Is.EqualTo(ScriptureRef.Parse("MAT 1:1")),
+                string.Join(",", rows.ToList().Select(tr => tr.Ref.ToString()))
+            );
+            Assert.That(
+                rows[0].Text,
+                Is.EqualTo("Last segment"),
+                string.Join(",", rows.ToList().Select(tr => tr.Text))
+            );
         });
     }
 
@@ -67,7 +83,32 @@ public void GetRows_DuplicateVerseWithTable()
             includeAllText: true
         );
 
-        Assert.That(rows, Has.Length.EqualTo(5));
+        Assert.That(rows, Has.Length.EqualTo(5), string.Join(",", rows.ToList().Select(tr => tr.Text)));
+    }
+
+    [Test]
+    public void GetRows_TriplicateVerse()
+    {
+        TextRow[] rows = GetRows(
+            @"\id MAT - Test
+\c 1
+\v 1 First verse 1
+\rem non verse 1
+\v 1 First verse 2
+\rem non verse 2
+\v 1 First verse 3
+\rem non verse 3
+\v 2 Second verse
+",
+            includeAllText: true
+        );
+        Assert.Multiple(() =>
+        {
+            Assert.That(rows, Has.Length.EqualTo(5), string.Join(",", rows.ToList().Select(tr => tr.Text)));
+            Assert.That(rows[0].Text, Is.EqualTo("First verse 1"));
+            Assert.That(rows[3].Text, Is.EqualTo("non verse 3"));
+            Assert.That(rows[4].Text, Is.EqualTo("Second verse"));
+        });
     }
 
     [Test]
@@ -88,7 +129,7 @@ public void GetRows_VersePara_BeginningNonVerseSegment()
             includeAllText: true
         );
 
-        Assert.That(rows, Has.Length.EqualTo(4));
+        Assert.That(rows, Has.Length.EqualTo(4), string.Join(",", rows.ToList().Select(tr => tr.Text)));
     }
 
     private static TextRow[] GetRows(string usfm, bool includeMarkers = false, bool includeAllText = false)