vim-patch:9.0.0110: help tag generation picks up words in code examples

Problem:    Help tag generation picks up words in code examples.
Solution:   Skip over examples. (Carlo Teubner, closes vim/vim#10813)

https://github.com/vim/vim/commit/ddab3ce3457aadffb16ce0127f67a99966a065a8

Also fix mistakes in help files.

Co-authored-by: Carlo Teubner <carlo@cteubner.net>

4 files changed, 23 insertions, 3 deletions

diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index 08c8e2e9d6..f9917ed035 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -8003,7 +8003,7 @@ stridx({haystack}, {needle} [, {start}])		*stridx()*
 
 		Can also be used as a |method|: >
 			GetHaystack()->stridx(needle)
-
+<
 							*string()*
 string({expr})	Return {expr} converted to a String.  If {expr} is a Number,
 		Float, String, Blob or a composition of them, then the result
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index eb42e10338..c989b67b96 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -1780,7 +1780,7 @@ v:exiting	Exit code, or |v:null| before invoking the |VimLeavePre|
 		and |VimLeave| autocmds.  See |:q|, |:x| and |:cquit|.
 		Example: >
 			:au VimLeave * echo "Exit value is " .. v:exiting
-
+<
 					*v:echospace* *echospace-variable*
 v:echospace	Number of screen cells that can be used for an `:echo` message
 		in the last screen line before causing the |hit-enter-prompt|.
diff --git a/src/nvim/help.c b/src/nvim/help.c
index 37d240e5c6..2095925db3 100644
--- a/src/nvim/help.c
+++ b/src/nvim/help.c
@@ -941,6 +941,7 @@ static void helptags_one(char *dir, const char *ext, const char *tagfname, bool
     }
     const char *const fname = files[fi] + dirlen + 1;
 
+    bool in_example = false;
     bool firstline = true;
     while (!vim_fgets(IObuff, IOSIZE, fd) && !got_int) {
       if (firstline) {
@@ -971,6 +972,13 @@ static void helptags_one(char *dir, const char *ext, const char *tagfname, bool
         }
         firstline = false;
       }
+      if (in_example) {
+        // skip over example; a non-white in the first column ends it
+        if (vim_strchr(" \t\n\r", IObuff[0])) {
+          continue;
+        }
+        in_example = false;
+      }
       p1 = vim_strchr((char *)IObuff, '*');       // find first '*'
       while (p1 != NULL) {
         p2 = strchr((const char *)p1 + 1, '*');  // Find second '*'.
@@ -990,7 +998,7 @@ static void helptags_one(char *dir, const char *ext, const char *tagfname, bool
                   || s[1] == '\0')) {
             *p2 = '\0';
             p1++;
-            size_t s_len= (size_t)(p2 - p1) + strlen(fname) + 2;
+            size_t s_len = (size_t)(p2 - p1) + strlen(fname) + 2;
             s = xmalloc(s_len);
             GA_APPEND(char *, &ga, s);
             snprintf(s, s_len, "%s\t%s", p1, fname);
@@ -1001,6 +1009,11 @@ static void helptags_one(char *dir, const char *ext, const char *tagfname, bool
         }
         p1 = p2;
       }
+      size_t len = strlen(IObuff);
+      if ((len == 2 && strcmp(&IObuff[len - 2], ">\n") == 0)
+          || (len >= 3 && strcmp(&IObuff[len - 3], " >\n") == 0)) {
+        in_example = true;
+      }
       line_breakcheck();
     }
 
diff --git a/src/nvim/testdir/test_help.vim b/src/nvim/testdir/test_help.vim
index 6cebc49b61..08dd3dcb9a 100644
--- a/src/nvim/testdir/test_help.vim
+++ b/src/nvim/testdir/test_help.vim
@@ -156,6 +156,13 @@ func Test_helptag_cmd()
   call assert_equal(["help-tags\ttags\t1"], readfile('Xdir/tags'))
   call delete('Xdir/tags')
 
+  " Test parsing tags
+  call writefile(['*tag1*', 'Example: >', '  *notag*', 'Example end: *tag2*'],
+    \ 'Xdir/a/doc/sample.txt')
+  helptags Xdir
+  call assert_equal(["tag1\ta/doc/sample.txt\t/*tag1*",
+                  \  "tag2\ta/doc/sample.txt\t/*tag2*"], readfile('Xdir/tags'))
+
   " Duplicate tags in the help file
   call writefile(['*tag1*', '*tag1*', '*tag2*'], 'Xdir/a/doc/sample.txt')
   call assert_fails('helptags Xdir', 'E154:')