patch 9.1.1533: helptoc: does not handle code sections in markdown well

Problem:  helptoc: does not handle code sections in markdown well
          (VimWei)
Solution: Skip over fenced code sections (lacygoill), add a test.

fixes: #17699
closes: #17710

Co-authored-by: lagygoill <lacygoill@lacygoill.me>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/pack/dist/opt/helptoc/autoload/helptoc.vim

@@ -1,4 +1,10 @@
 vim9script noclear
+
+# the Vim HelpTOC plugin, creates a table of contents in a popup
+# Maintainer: Vim project
+# Original Author: @lacygoill
+# Latest Change: 2025 Jul 09
+#
 # Config {{{1
 # g:helptoc {{{2
 # Create the g:helptoc dict (used to specify the shell_prompt and other
@@ -503,6 +509,7 @@ def SetToc() #{{{2
             l[0]->str2nr() - ll[0]->str2nr())
 
     var skip_next: bool = false
+    var skip_fence: bool = false
 
     # Non-help headings processing
     for lnum: number in range(1, line('$'))
@@ -516,6 +523,14 @@ def SetToc() #{{{2
 
         # Special handling for markdown filetype using setext headings
         if g:helptoc.type == 'markdown'
+            if curline =~ '^```.'
+                skip_fence = true
+            elseif curline =~ '^```$'
+                skip_fence = false
+            endif
+            if skip_fence
+                continue
+            endif
             # Check for setext formatted headings (= or - underlined)
             if nextline =~ '^\s\{0,3}=\+$' && curline =~ '\S'
                 # Level 1 heading (one or more =, up to three spaces preceding)

src/testdir/Make_all.mak

@@ -242,6 +242,7 @@ NEW_TESTS = \
 	test_perl \
 	test_plugin_comment \
 	test_plugin_glvs \
+	test_plugin_helptoc \
 	test_plugin_man \
 	test_plugin_matchparen \
 	test_plugin_termdebug \
@@ -513,6 +514,7 @@ NEW_TESTS_RES = \
 	test_perl.res \
 	test_plugin_comment.res \
 	test_plugin_glvs.res \
+	test_plugin_helptoc.res \
 	test_plugin_man.res \
 	test_plugin_matchparen.res \
 	test_plugin_termdebug.res \

src/testdir/dumps/Test_helptoc_markdown_01.dump

@@ -0,0 +1,20 @@
+|#+0#e000e06#ffffff0| |M|y| |D|o|c|u|m|e|n|t| +0#0000000&@27|┌| |1|/|1| |(|1|/|1|)| @2|p|r|e|s@1| |?| |f|o|r| |h|e|l|p| |─@1|┐
+| @40|│| |M+0#0000001#e0e0e08|y| |D|o|c|u|m|e|n|t| @18| +0#0000000#ffffff0|│
+|S|o|m|e| |t|e|x|t|.| @30|│| | +0#4040ff13&@29| +0#0000000&|│
+| @40|│| | +0#4040ff13&@29| +0#0000000&|│
+|`+0#e000e06&@2|v|i|m| +0#0000000&@34|│| | +0#4040ff13&@29| +0#0000000&|│
+|#| |T|h|i|s| |i|s| |a| |V|i|m|9|S|c|r|i|p|t| |c|o|m@1|e|n|t| @10|│| | +0#4040ff13&@29| +0#0000000&|│
+|d|e|f| |M|y|F|u|n|c|(|)| @28|│| | +0#4040ff13&@29| +0#0000000&|│
+| @1|#| |A|n|o|t|h|e|r| |c|o|m@1|e|n|t| @21|│| | +0#4040ff13&@29| +0#0000000&|│
+|e|n|d@1|e|f| @34|│| | +0#4040ff13&@29| +0#0000000&|│
+|`+0#e000e06&@2| +0#0000000&@37|│| | +0#4040ff13&@29| +0#0000000&|│
+> @40|│| | +0#4040ff13&@29| +0#0000000&|│
+|~+0#4040ff13&| @39|│+0#0000000&| | +0#4040ff13&@29| +0#0000000&|│
+|~+0#4040ff13&| @39|│+0#0000000&| | +0#4040ff13&@29| +0#0000000&|│
+|~+0#4040ff13&| @39|│+0#0000000&| | +0#4040ff13&@29| +0#0000000&|│
+|~+0#4040ff13&| @39|│+0#0000000&| | +0#4040ff13&@29| +0#0000000&|│
+|~+0#4040ff13&| @39|│+0#0000000&| | +0#4040ff13&@29| +0#0000000&|│
+|~+0#4040ff13&| @39|│+0#0000000&| | +0#4040ff13&@29| +0#0000000&|│
+|~+0#4040ff13&| @39|│+0#0000000&| | +0#4040ff13&@29| +0#0000000&|│
+|~+0#4040ff13&| @39|└+0#0000000&|─@31|┘
+|:|H|e|l|p|T|o|c| @48|1@1|,|0|-|1| @7|A|l@1| 

src/testdir/test_plugin_helptoc.vim

@@ -0,0 +1,32 @@
+" Test for the HelpTOC package
+
+source util/screendump.vim
+
+func Test_helptoc_markdown_with_comments()
+  CheckScreendump
+  let lines =<< trim END
+    packadd helptoc
+    e Xmarkdown.md
+    call append(0, [
+          \ '# My Document',
+          \ '', 'Some text.',
+          \ '',
+          \ '```vim',
+          \ '# This is a Vim9Script comment',
+          \ 'def MyFunc()',
+          \ '  # Another comment',
+          \ 'enddef',
+          \ '```'
+          \])
+  END
+
+  let input_file = "Xhelptoc.vim"
+  call writefile(lines, input_file, "D")
+
+  let buf = RunVimInTerminal($"-S {input_file}", {})
+  call term_sendkeys(buf, ":HelpToc\<cr>")
+  call WaitFor({-> term_getline(buf, 1) =~ 'press ? for help'})
+  call VerifyScreenDump(buf, 'Test_helptoc_markdown_01', {})
+  call term_sendkeys(buf, ":qa!\<cr>")
+  call StopVimInTerminal(buf)
+endfunc

src/version.c

@@ -719,6 +719,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1533,
 /**/
     1532,
 /**/