vim-patch:8.0.0453 (#6266)

Problem:    Adding fold marker creates new comment.
Solution:   Use an existing comment if possible. (LemonBoy, closes vim/vim#1549)

https://github.com/vim/vim/commit/025a6b708a9bff54c73fb9c641b980da19e943a9

4 files changed, 58 insertions, 33 deletions

diff --git a/src/nvim/fold.c b/src/nvim/fold.c
index 1423463800..7c0283971e 100644
--- a/src/nvim/fold.c
+++ b/src/nvim/fold.c
@@ -29,6 +29,7 @@
 #include "nvim/strings.h"
 #include "nvim/syntax.h"
 #include "nvim/undo.h"
+#include "nvim/ops.h"
 
 /* local declarations. {{{1 */
 /* typedef fold_T {{{2 */
@@ -1593,29 +1594,32 @@ static void foldCreateMarkers(linenr_T start, linenr_T end)
 /*
  * Add "marker[markerlen]" in 'commentstring' to line "lnum".
  */
-static void foldAddMarker(linenr_T lnum, char_u *marker, size_t markerlen)
+static void foldAddMarker(linenr_T lnum, const char_u *marker, size_t markerlen)
 {
   char_u      *cms = curbuf->b_p_cms;
   char_u      *line;
   char_u      *newline;
   char_u      *p = (char_u *)strstr((char *)curbuf->b_p_cms, "%s");
+  bool line_is_comment = false;
 
-  /* Allocate a new line: old-line + 'cms'-start + marker + 'cms'-end */
+  // Allocate a new line: old-line + 'cms'-start + marker + 'cms'-end
   line = ml_get(lnum);
   size_t line_len = STRLEN(line);
 
   if (u_save(lnum - 1, lnum + 1) == OK) {
+    // Check if the line ends with an unclosed comment
+    skip_comment(line, false, false, &line_is_comment);
     newline = xmalloc(line_len + markerlen + STRLEN(cms) + 1);
     STRCPY(newline, line);
-    if (p == NULL)
+    // Append the marker to the end of the line
+    if (p == NULL || line_is_comment) {
       STRLCPY(newline + line_len, marker, markerlen + 1);
-    else {
+    } else {
       STRCPY(newline + line_len, cms);
       memcpy(newline + line_len + (p - cms), marker, markerlen);
       STRCPY(newline + line_len + (p - cms) + markerlen, p + 2);
     }
-
-    ml_replace(lnum, newline, FALSE);
+    ml_replace(lnum, newline, false);
   }
 }
 
@@ -2535,10 +2539,10 @@ static void foldSplit(garray_T *gap, int i, linenr_T top, linenr_T bot)
  *      1  2  3
  *      1  2  3
  * top     2  3  4  5
- *	   2  3  4  5
- * bot	   2  3  4  5
- *	      3     5  6
- *	      3     5  6
+ *     2  3  4  5
+ * bot     2  3  4  5
+ *        3     5  6
+ *        3     5  6
  *
  * 1: not changed
  * 2: truncate to stop above "top"
diff --git a/src/nvim/memline.c b/src/nvim/memline.c
index b67f550358..1a315fce8b 100644
--- a/src/nvim/memline.c
+++ b/src/nvim/memline.c
@@ -2318,7 +2318,7 @@ ml_append_int (
  *
  * return FAIL for failure, OK otherwise
  */
-int ml_replace(linenr_T lnum, char_u *line, int copy)
+int ml_replace(linenr_T lnum, char_u *line, bool copy)
 {
   if (line == NULL)             /* just checking... */
     return FAIL;
diff --git a/src/nvim/ops.c b/src/nvim/ops.c
index 530193bd41..1e4d392754 100644
--- a/src/nvim/ops.c
+++ b/src/nvim/ops.c
@@ -3438,43 +3438,47 @@ dis_msg (
   os_breakcheck();
 }
 
-/*
- * If "process" is TRUE and the line begins with a comment leader (possibly
- * after some white space), return a pointer to the text after it. Put a boolean
- * value indicating whether the line ends with an unclosed comment in
- * "is_comment".
- * line - line to be processed,
- * process - if FALSE, will only check whether the line ends with an unclosed
- *	     comment,
- * include_space - whether to also skip space following the comment leader,
- * is_comment - will indicate whether the current line ends with an unclosed
- *		comment.
- */
-static char_u *skip_comment(char_u *line, int process, int include_space, int *is_comment)
+/// If \p "process" is true and the line begins with a comment leader (possibly
+/// after some white space), return a pointer to the text after it.
+/// Put a boolean value indicating whether the line ends with an unclosed
+/// comment in "is_comment".
+///
+/// @param line - line to be processed
+/// @param process - if false, will only check whether the line ends
+///         with an unclosed comment,
+/// @param include_space - whether to skip space following the comment leader
+/// @param[out] is_comment - whether the current line ends with an unclosed
+///  comment.
+char_u *skip_comment(
+    char_u *line, bool process, bool include_space, bool *is_comment
+)
 {
   char_u *comment_flags = NULL;
   int lead_len;
   int leader_offset = get_last_leader_offset(line, &comment_flags);
 
-  *is_comment = FALSE;
+  *is_comment = false;
   if (leader_offset != -1) {
     /* Let's check whether the line ends with an unclosed comment.
      * If the last comment leader has COM_END in flags, there's no comment.
      */
     while (*comment_flags) {
       if (*comment_flags == COM_END
-          || *comment_flags == ':')
+          || *comment_flags == ':') {
         break;
-      ++comment_flags;
+      }
+      comment_flags++;
+    }
+    if (*comment_flags != COM_END) {
+      *is_comment = true;
     }
-    if (*comment_flags != COM_END)
-      *is_comment = TRUE;
   }
 
-  if (process == FALSE)
+  if (process == false) {
     return line;
+  }
 
-  lead_len = get_leader_len(line, &comment_flags, FALSE, include_space);
+  lead_len = get_leader_len(line, &comment_flags, false, include_space);
 
   if (lead_len == 0)
     return line;
@@ -3496,8 +3500,9 @@ static char_u *skip_comment(char_u *line, int process, int include_space, int *i
    * starting with a closing part of a three-part comment. That's good,
    * because we don't want to remove those as this would be annoying.
    */
-  if (*comment_flags == ':' || *comment_flags == NUL)
+  if (*comment_flags == ':' || *comment_flags == NUL) {
     line += lead_len;
+  }
 
   return line;
 }
@@ -3531,7 +3536,7 @@ int do_join(size_t count,
   int         *comments = NULL;
   int remove_comments = (use_formatoptions == TRUE)
                         && has_format_option(FO_REMOVE_COMS);
-  int prev_was_comment;
+  bool prev_was_comment;
 
   if (save_undo && u_save(curwin->w_cursor.lnum - 1,
                           curwin->w_cursor.lnum + (linenr_T)count) == FAIL) {
diff --git a/src/nvim/testdir/test_fold.vim b/src/nvim/testdir/test_fold.vim
index 1f835b876f..7cb9faa75f 100644
--- a/src/nvim/testdir/test_fold.vim
+++ b/src/nvim/testdir/test_fold.vim
@@ -96,6 +96,22 @@ func! Test_indent_fold2()
     bw!
 endfunc
 
+func Test_folds_marker_in_comment()
+  new
+  call setline(1, ['" foo', 'bar', 'baz'])
+  setl fen fdm=marker
+  setl com=sO:\"\ -,mO:\"\ \ ,eO:\"\",:\" cms=\"%s
+  norm! zf2j
+  setl nofen
+  :1y
+  call assert_equal(['" foo{{{'], getreg(0,1,1))
+  :+2y
+  call assert_equal(['baz"}}}'], getreg(0,1,1))
+
+  set foldmethod&
+  bwipe!
+endfunc
+
 func Test_manual_fold_with_filter()
   if !executable('cat')
     return