Fix PreserveParagraphStyles

src/SIL.Machine/Corpora/UpdateUsfmParserHandler.cs

@@ -420,8 +420,9 @@ private bool ReplaceWithNewTokens(UsfmParserState state, bool closed = true)
                 .Any(t => t.Type == UsfmTokenType.Text && t.Text.Length > 0);
 
             bool useNewTokens =
-                (
-                    (_textBehavior == UpdateUsfmTextBehavior.StripExisting && !IsInPreservedParagraph(marker))
+                !IsInPreservedParagraph(marker)
+                && (
+                    _textBehavior == UpdateUsfmTextBehavior.StripExisting
                     || (HasNewText() && (!existingText || _textBehavior != UpdateUsfmTextBehavior.PreferExisting))
                 )
                 && (!inEmbed || (InNoteText && !inNestedEmbed && _embedBehavior == UpdateUsfmMarkerBehavior.Preserve));
@@ -433,8 +434,10 @@ private bool ReplaceWithNewTokens(UsfmParserState state, bool closed = true)
                 else
                     AddNewTokens();
             }
-
-            if (existingText && _textBehavior == UpdateUsfmTextBehavior.PreferExisting)
+            if (
+                existingText
+                && (_textBehavior == UpdateUsfmTextBehavior.PreferExisting || IsInPreservedParagraph(marker))
+            )
             {
                 if (inEmbed)
                     ClearNewEmbedTokens();

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

@@ -98,6 +98,60 @@ public void GetUsfm_StripAllText()
         Assess(target, result);
     }
 
+    [Test]
+    public void GetUsfm_StripParagraphs_PreserveParagraphStyles()
+    {
+        var rows = new List<(IReadOnlyList<ScriptureRef>, string)>
+        {
+            (ScrRef("MAT 1:0/1:rem"), "New remark"),
+            (ScrRef("MAT 1:0/3:ip"), "Another new remark"),
+            (ScrRef("MAT 1:1"), "Update 1"),
+        };
+        string usfm =
+            @"\id MAT
+\c 1
+\rem Update remark
+\r reference
+\ip This is another remark, but with a different marker
+\v 1 This is a verse
+";
+
+        string target = UpdateUsfm(
+            rows,
+            usfm,
+            textBehavior: UpdateUsfmTextBehavior.StripExisting,
+            paragraphBehavior: UpdateUsfmMarkerBehavior.Strip
+        );
+        string result =
+            @"\id MAT
+\c 1
+\rem Update remark
+\r reference
+\ip Another new remark
+\v 1 Update 1
+";
+
+        Assess(target, result);
+
+        var targetDiffParagraph = UpdateUsfm(
+            rows,
+            usfm,
+            textBehavior: UpdateUsfmTextBehavior.StripExisting,
+            paragraphBehavior: UpdateUsfmMarkerBehavior.Strip,
+            preserveParagraphStyles: ImmutableHashSet.Create("ip")
+        );
+        string resultDiffParagraph =
+            @"\id MAT
+\c 1
+\rem New remark
+\r
+\ip This is another remark, but with a different marker
+\v 1 Update 1
+";
+
+        Assess(targetDiffParagraph, resultDiffParagraph);
+    }
+
     [Test]
     public void GetUsfm_PreserveParagraphs()
     {
@@ -167,7 +221,6 @@ public void GetUsfm_ParagraphInVerse()
 \v 2 Verse 2
 \p inner verse paragraph
 ";
-
         Assess(target, result);
 
         string targetStrip = UpdateUsfm(
@@ -184,6 +237,7 @@ public void GetUsfm_ParagraphInVerse()
 \s1
 \v 2
 ";
+        // Assert.Fail(targetStrip);
 
         Assess(targetStrip, resultStrip);
     }