vim-patch:9.2.0640: the "%" command jumps to parens and braces inside comments (#40229)

Problem:  The "%" command jumps to parens and braces inside comments,
          unlike the "=" operator (cindent), which ignores them.
Solution: When 'comments' defines C-style comments and "%" is not in
          'cpoptions', skip matching parens inside such comments, except
          when the cursor is inside a comment so a match there can still
          be found.

fixes:   vim/vim#20329
related: vim/vim#20111
closes:  vim/vim#20491

b8a109dcfb

Co-authored-by: Hirohito Higashi <h.east.727@gmail.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

runtime/doc/motion.txt

@@ -1338,9 +1338,13 @@ remembered.
 			quotes).  Note that this works fine for C, but not for
 			Perl, where single quotes are used for strings.
 
-			Nothing special is done for matches in comments.  You
-			can either use the |matchit| plugin or put quotes around
-			matches.
+			When in addition 'comments' defines C-style "//" or
+			"/*" comments, parens and braces inside such comments
+			are skipped, like the |=| operator does.  This does
+			not happen when the cursor is inside a comment, so a
+			match inside that comment can still be found.
+			Otherwise you can use the |matchit| plugin or put
+			quotes around matches.
 
 			No count is allowed, {count}% jumps to a line {count}
 			percentage down the file |N%|.  Using '%' on

src/nvim/normal.c

@@ -4356,6 +4356,23 @@ static void nv_brackets(cmdarg_T *cap)
   }
 }
 
+/// Return true when 'comments' defines a C-style line ("//") or block comment.
+/// This is when "%" should skip matching parens in comments, like the "="
+/// operator does.
+static bool buf_has_cstyle_comments(void)
+{
+  char part_buf[COM_MAX_LEN];  // buffer for one 'comments' part
+
+  for (char *list = curbuf->b_p_com; *list;) {
+    (void)copy_option_part(&list, part_buf, COM_MAX_LEN, ",");
+    char *string = vim_strchr(part_buf, ':');  // flags and comment leader
+    if (string != NULL && string[1] == '/' && (string[2] == '/' || string[2] == '*')) {
+      return true;
+    }
+  }
+  return false;
+}
+
 /// Handle Normal mode "%" command.
 static void nv_percent(cmdarg_T *cap)
 {
@@ -4384,10 +4401,21 @@ static void nv_percent(cmdarg_T *cap)
       beginline(BL_SOL | BL_FIX);
     }
   } else {  // "%" : go to matching paren
+    int flags = 0;
+    // Skip matching parens inside C-style comments, like the "=" operator
+    // does, but not when "%" is in 'cpoptions' (Vi-compatible) or the
+    // cursor sits in a line comment (so a match there can still be found).
+    if (vim_strchr(p_cpo, CPO_MATCH) == NULL && buf_has_cstyle_comments()) {
+      int comment_col = check_linecomment(get_cursor_line_ptr());
+      if (comment_col == MAXCOL || curwin->w_cursor.col < (colnr_T)comment_col) {
+        flags = FM_SKIPCOMM;
+      }
+    }
+
     pos_T *pos;
     cap->oap->motion_type = kMTCharWise;
     cap->oap->use_reg_one = true;
-    if ((pos = findmatch(cap->oap, NUL)) == NULL) {
+    if ((pos = findmatchlimit(cap->oap, NUL, flags, 0)) == NULL) {
       clearopbeep(cap->oap);
     } else {
       setpcmark();

test/old/testdir/test_normal.vim

@@ -3908,6 +3908,70 @@ func Test_normal_percent_jump()
   bwipe!
 endfunc
 
+" Test that "%" skips parens inside comments when 'comments' defines C-style
+" "//" or "/*" comments.
+func Test_normal_percent_skip_comment()
+  new
+  setlocal comments=s1:/*,mb:*,ex:*/,://
+
+  " Forward: skip a ")" inside a // comment, match the real one.
+  silent! %delete _
+  call setline(1, ['foo(  // )', ');'])
+  call cursor(1, 4)
+  normal %
+  call assert_equal([2, 1], [line('.'), col('.')])
+
+  " Forward: skip a ")" inside a /* */ comment, match the real one.
+  silent! %delete _
+  call setline(1, ['bar( /* ) */ x)'])
+  call cursor(1, 4)
+  normal %
+  call assert_equal([1, 15], [line('.'), col('.')])
+
+  " Backward: skip a "(" inside a // comment, match the real one.
+  silent! %delete _
+  call setline(1, ['( // (', ')'])
+  call cursor(2, 1)
+  normal %
+  call assert_equal([1, 1], [line('.'), col('.')])
+
+  " Cursor inside a // comment: a match inside that comment is still found.
+  silent! %delete _
+  call setline(1, ['x // ( y )'])
+  call cursor(1, 6)
+  normal %
+  call assert_equal([1, 10], [line('.'), col('.')])
+
+  " Cursor inside a /* */ comment: a match inside that comment is still found.
+  silent! %delete _
+  call setline(1, ['/* a ( b ) c */'])
+  call cursor(1, 6)
+  normal %
+  call assert_equal([1, 10], [line('.'), col('.')])
+
+  " When 'comments' has no C-style comments the parens are not skipped.
+  setlocal comments=b:#
+  silent! %delete _
+  call setline(1, ['foo(  // )', ');'])
+  call cursor(1, 4)
+  normal %
+  call assert_equal([1, 10], [line('.'), col('.')])
+
+  " With "%" in 'cpoptions' Vi-compatible matching is used and the parens
+  " inside comments are not skipped.
+  let save_cpo = &cpoptions
+  setlocal comments=s1:/*,mb:*,ex:*/,://
+  set cpoptions+=%
+  silent! %delete _
+  call setline(1, ['foo(  // )', ');'])
+  call cursor(1, 4)
+  normal %
+  call assert_equal([1, 10], [line('.'), col('.')])
+  let &cpoptions = save_cpo
+
+  bwipe!
+endfunc
+
 " Test for << and >> commands to shift text by 'shiftwidth'
 func Test_normal_shift_rightleft()
   new