Ignore trailing blank lines after single-line title-page commands.

CHANGES.md

@@ -16,6 +16,10 @@ This file describes changes in the AutoDoc package.
     `<Keyword>...</Keyword>` for GAP keywords (as returned by
     `ALL_KEYWORDS()`), otherwise as before `<Code>...</Code>`
   - Allow XML-style comments in `.autodoc` files
+  - Ignore trailing blank lines after single-line worksheet title-page
+    commands such as `@Title`, `@Subtitle`, `@Version`, `@Author`, and
+    `@Date`, and trim trailing blank lines from generated title-page
+    content so they no longer leak into filenames or empty author entries
   - Greatly improve the package manual.
   - Convert the hand-written manual chapters from XML to `.autodoc`
   - Fix an unexpected and confusing error when mixing explicit

gap/AutoDocMainFunction.gi

@@ -224,7 +224,7 @@ end );
 InstallGlobalFunction( CreateTitlePage,
   function( dir, argument_rec )
     local indent, tag, names, filestream, entity_list, OutWithTag, Out, i,
-          parsed_date;
+          parsed_date, NormalizeTitlePageContent;
 
     filestream := AUTODOC_OutputTextFile( dir, "title.xml" );
     indent := 0;
@@ -255,19 +255,42 @@ InstallGlobalFunction( CreateTitlePage,
         AppendTo( filestream, s, "</", tag, ">\n" );
     end;
 
+    # Parser state can leave title-page fields as a list of lines. Normalize
+    # them here so trailing blank lines do not leak into output or filenames,
+    # while still preserving intentional internal line breaks for multiline fields.
+    NormalizeTitlePageContent := function( content )
+        local normalized;
+
+        if IsString( content ) then
+            content := [ content ];
+        fi;
+        normalized := List( content, line -> StripBeginEnd( line, "\n\r" ) );
+        while Length( normalized ) > 0 and
+              IsString( normalized[ Length( normalized ) ] ) and
+              StripBeginEnd( normalized[ Length( normalized ) ], " \t\r\n" ) = "" do
+            Remove( normalized );
+        od;
+        if Length( normalized ) = 1 then
+            return normalized[ 1 ];
+        fi;
+        return normalized;
+    end;
+
     Out( AUTODOC_XML_HEADER );
     Out( "<TitlePage>\n" );
     indent := indent + 1;
 
     for i in [ "Title", "Subtitle", "Version", "TitleComment" ] do
         if IsBound( argument_rec.( i ) ) then
-            OutWithTag( i, argument_rec.( i ) );
+            OutWithTag( i, NormalizeTitlePageContent( argument_rec.( i ) ) );
         fi;
     od;
 
     if IsBound( argument_rec.Author ) then
-        for i in argument_rec.Author do
-            OutWithTag( "Author", i );
+        for i in List( argument_rec.Author, NormalizeTitlePageContent ) do
+            if not IsString( i ) or StripBeginEnd( i, " \t\r\n" ) <> "" then
+                OutWithTag( "Author", i );
+            fi;
         od;
     fi;
 
@@ -282,12 +305,12 @@ InstallGlobalFunction( CreateTitlePage,
                 argument_rec.Date := AUTODOC_FormatDate( parsed_date );
             fi;
         fi;
-        OutWithTag( "Date", argument_rec.Date );
+        OutWithTag( "Date", NormalizeTitlePageContent( argument_rec.Date ) );
     fi;
 
     for i in [ "Address", "Abstract", "Copyright", "Acknowledgements", "Colophon" ] do
         if IsBound( argument_rec.( i ) ) then
-            OutWithTag( i, StripBeginEnd( argument_rec.( i ), "\n\r" ) );
+            OutWithTag( i, NormalizeTitlePageContent( argument_rec.( i ) ) );
         fi;
     od;
 

gap/Parser.gi

@@ -218,6 +218,7 @@ InstallGlobalFunction( AutoDoc_Parser_ReadFiles,
           scope_group, read_example, command_function_record, autodoc_read_line,
           current_command, filename, groupnumber, rest_of_file_skipped,
           context_stack, new_man_item, add_man_item, Reset, read_code, title_item, title_item_list, plain_text_mode,
+          single_line_title_item_list, active_title_item_name, active_title_item_is_multiline,
           current_line_unedited, current_line_info, NormalizeInputLine,
           ReadLineWithLineCount, Normalized_ReadLine, line_number, ErrorWithPos, create_title_item_function,
           current_line_positition_for_filter, read_session_example, DeclarationDelimiterPosition,
@@ -231,6 +232,8 @@ InstallGlobalFunction( AutoDoc_Parser_ReadFiles,
     context_stack := [ ];
     chapter_info := [ ];
     line_number := 0;
+    active_title_item_name := fail;
+    active_title_item_is_multiline := false;
 
     ReadLineWithLineCount := function( stream )
         line_number := line_number + 1;
@@ -964,6 +967,10 @@ InstallGlobalFunction( AutoDoc_Parser_ReadFiles,
             if not IsBound( current_item ) then
                 return;
             fi;
+            if active_title_item_name <> fail and
+               active_title_item_is_multiline = false then
+                return;
+            fi;
             Add( current_item, current_command[ 2 ] );
         end,
         @BeginLatexOnly := function()
@@ -1022,13 +1029,17 @@ InstallGlobalFunction( AutoDoc_Parser_ReadFiles,
     ## information directly into the document.
     title_item_list := [ "Title", "Subtitle", "Version", "TitleComment", "Author",
                          "Date", "Address", "Abstract", "Copyright", "Acknowledgements", "Colophon" ];
-
+    single_line_title_item_list := [ "Title", "Subtitle", "Version", "Author", "Date" ];
+
     create_title_item_function := function( name )
         return function()
             if not IsBound( tree!.TitlePage.( name ) ) then
                 tree!.TitlePage.( name ) := [ ];
             fi;
             current_item := tree!.TitlePage.( name );
+            active_title_item_name := name;
+            active_title_item_is_multiline :=
+                Position( single_line_title_item_list, name ) = fail;
             Add( current_item, current_command[ 2 ] );
         end;
     end;
@@ -1116,6 +1127,11 @@ InstallGlobalFunction( AutoDoc_Parser_ReadFiles,
             fi;
             if current_command[ 1 ] <> false then
                 autodoc_read_line := current_line_info.allows_declaration_scan;
+                if Position( title_item_list, current_command[ 1 ]{ [ 2 .. Length( current_command[ 1 ] ) ] } ) = fail and
+                   current_command[ 1 ] <> "STRING" then
+                    active_title_item_name := fail;
+                    active_title_item_is_multiline := false;
+                fi;
                 if not IsBound( command_function_record.(current_command[ 1 ]) ) then
                     ErrorWithPos("unknown AutoDoc command ", current_command[ 1 ]);
                 fi;

tst/worksheets/paired-titlepage-autoplain.sheet/plain.autodoc

@@ -1,13 +1,23 @@
 @Title Paired Titlepage Test
+
 @Subtitle Comment mode title coverage
+
 @Version 2.0
+
 @TitleComment Internal worksheet fixture
+
 @Author Ada Example
+
 @Date 2026-03-07
+
 @Address Example Street 7
+
 @Abstract This worksheet exercises title-page commands in plain-text mode.
+
 @Copyright 2026 Example Authors
+
 @Acknowledgements Thanks to the worksheet harness.
+
 @Colophon Generated for AutoDoc regression coverage.
 @Chapter Titlepage Chapter
 @Section Titlepage Section