patch 9.2.0447: cindent does not ignore comments

Problem:  When find_start_brace() scans backwards for the enclosing
          block, '{' and '}' inside // and /* */ comments are counted,
          producing wrong indent for code following such comments
          (rendcrx).
Solution: Implement FM_SKIPCOMM in findmatchlimit() to track block-
          comment state and skip matches inside comments. Pass
          FM_SKIPCOMM from cindent's call sites
          (find_start_brace, find_match_char, cin_iswhileofdo,
          get_c_indent).

fixes:  #4
fixes:  #648
fixes:  #19578
closes: #19581
closes: #20111

Signed-off-by: magnus-rattlehead <guranjakustivi@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/version9.txt

@@ -1,4 +1,4 @@
-*version9.txt*	For Vim version 9.2.  Last change: 2026 May 02
+*version9.txt*	For Vim version 9.2.  Last change: 2026 May 05
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -52625,6 +52625,7 @@ Other ~
 - Added the "u" flag to 'shortmess' to silence undo/redo messages: |shm-u|
 - |:command-completion-customlist| can return a list of dictionaries with
   kind/menu/info/abbr for the popup menu.
+- |C-indenting| detects comments better.
 
 Platform specific ~
 -----------------

src/cindent.c

@@ -1153,7 +1153,7 @@ find_match_char(int c, int ind_maxparen)	// XXX
     cursor_save = curwin->w_cursor;
     ind_maxp_wk = ind_maxparen;
 retry:
-    if ((trypos = findmatchlimit(NULL, c, 0, ind_maxp_wk)) != NULL)
+    if ((trypos = findmatchlimit(NULL, c, FM_SKIPCOMM, ind_maxp_wk)) != NULL)
     {
 	// check if the ( is in a // comment
 	if ((colnr_T)cin_skip2pos(trypos) > trypos->col)
@@ -1396,7 +1396,7 @@ cin_iswhileofdo (char_u *p, linenr_T lnum)	// XXX
 	    ++p;
 	    ++curwin->w_cursor.col;
 	}
-	if ((trypos = findmatchlimit(NULL, 0, 0,
+	if ((trypos = findmatchlimit(NULL, 0, FM_SKIPCOMM,
 					      curbuf->b_ind_maxparen)) != NULL
 		&& *cin_skipcomment(ml_get_pos(trypos) + 1) == ';')
 	    retval = TRUE;
@@ -1732,7 +1732,7 @@ find_start_brace(void)	    // XXX
     static pos_T    pos_copy;
 
     cursor_save = curwin->w_cursor;
-    while ((trypos = findmatchlimit(NULL, '{', FM_BLOCKSTOP, 0)) != NULL)
+    while ((trypos = findmatchlimit(NULL, '{', FM_BLOCKSTOP | FM_SKIPCOMM, 0)) != NULL)
     {
 	pos_copy = *trypos;	// copy pos_T, next findmatch will change it
 	trypos = &pos_copy;
@@ -2547,7 +2547,7 @@ get_c_indent(void)
 		line = ml_get_curline();
 		look_col = (int)(look - line);
 		curwin->w_cursor.col = look_col + 1;
-		if ((trypos = findmatchlimit(NULL, ')', 0,
+		if ((trypos = findmatchlimit(NULL, ')', FM_SKIPCOMM,
 						      curbuf->b_ind_maxparen))
 								      != NULL
 			  && trypos->lnum == our_paren_pos.lnum

src/search.c

@@ -2165,7 +2165,7 @@ find_mps_values(
  * flags: FM_BACKWARD	search backwards (when initc is '/', '*' or '#')
  *	  FM_FORWARD	search forwards (when initc is '/', '*' or '#')
  *	  FM_BLOCKSTOP	stop at start/end of block ({ or } in column 0)
- *	  FM_SKIPCOMM	skip comments (not implemented yet!)
+ *	  FM_SKIPCOMM	skip over comments (cursor must start outside a block comment)
  *
  * "oap" is only used to set oap->motion_type for a linewise motion, it can be
  * NULL
@@ -2201,6 +2201,8 @@ findmatchlimit(
     int		comment_col = MAXCOL;   // start of / / comment
     int		lispcomm = FALSE;	// inside of Lisp-style comment
     int		lisp = curbuf->b_p_lisp; // engage Lisp-specific hacks ;)
+    int		skip_comments = (flags & FM_SKIPCOMM) != 0;
+    int		in_block_comment = FALSE; // inside /* */ block comment
 
     pos = curwin->w_cursor;
     pos.coladd = 0;
@@ -2429,10 +2431,14 @@ findmatchlimit(
     CLEAR_POS(&match_pos);
 
     // backward search: Check if this line contains a single-line comment
-    if ((backwards && comment_dir) || lisp)
+    if ((backwards && comment_dir) || lisp || skip_comments)
 	comment_col = check_linecomment(linep);
     if (lisp && comment_col != MAXCOL && pos.col > (colnr_T)comment_col)
 	lispcomm = TRUE;    // find match inside this comment
+    // skip // comment portion at starting position
+    if (skip_comments && !in_block_comment && comment_col != MAXCOL
+	    && backwards && pos.col > (colnr_T)comment_col)
+	pos.col = comment_col;
 
     while (!got_int)
     {
@@ -2460,11 +2466,15 @@ findmatchlimit(
 		line_breakcheck();
 
 		// Check if this line contains a single-line comment
-		if (comment_dir || lisp)
+		if (comment_dir || lisp || skip_comments)
 		    comment_col = check_linecomment(linep);
 		// skip comment
 		if (lisp && comment_col != MAXCOL)
 		    pos.col = comment_col;
+		else if (skip_comments && !in_block_comment
+			&& comment_col != MAXCOL
+			&& pos.col > (colnr_T)comment_col)
+		    pos.col = comment_col;
 	    }
 	    else
 	    {
@@ -2495,7 +2505,7 @@ findmatchlimit(
 		pos.col = 0;
 		do_quotes = -1;
 		line_breakcheck();
-		if (lisp)   // find comment pos in new line
+		if (lisp || skip_comments)   // find comment pos in new line
 		    comment_col = check_linecomment(linep);
 	    }
 	    else
@@ -2507,6 +2517,37 @@ findmatchlimit(
 	    }
 	}
 
+	// Track block comment state when FM_SKIPCOMM is set.
+	// Backward: '/' of end-marker enters comment; '*' of start-marker exits.
+	// Forward:  '/' of start-marker enters comment; '/' of end-marker exits.
+	if (skip_comments && !comment_dir)
+	{
+	    if (backwards)
+	    {
+		// Guard pos.col < comment_col: don't misread '*/' at the '//'
+		// position as a block-comment end-marker.
+		if (!in_block_comment && pos.col > 0
+			&& linep[pos.col - 1] == '*' && linep[pos.col] == '/'
+			&& (comment_col == MAXCOL || (int)pos.col < comment_col))
+		    in_block_comment = TRUE;
+		else if (in_block_comment && pos.col > 0
+			&& linep[pos.col - 1] == '/' && linep[pos.col] == '*')
+		    in_block_comment = FALSE;
+	    }
+	    else
+	    {
+		// Guard pos.col < comment_col: don't treat '/*' inside a '//'
+		// comment as a block-comment start-marker.
+		if (!in_block_comment && linep[pos.col] == '/'
+			&& linep[pos.col + 1] == '*'
+			&& (comment_col == MAXCOL || (int)pos.col < comment_col))
+		    in_block_comment = TRUE;
+		else if (in_block_comment && pos.col > 0
+			&& linep[pos.col - 1] == '*' && linep[pos.col] == '/')
+		    in_block_comment = FALSE;
+	    }
+	}
+
 	/*
 	 * If FM_BLOCKSTOP given, stop at a '{' or '}' in column 0.
 	 */
@@ -2750,6 +2791,11 @@ findmatchlimit(
 		    && check_prevcol(linep, pos.col - 1, '#', NULL))
 		break;
 
+	    // Skip matches inside comments when FM_SKIPCOMM is set.
+	    if (skip_comments && (in_block_comment
+		    || (comment_col != MAXCOL && (int)pos.col >= comment_col)))
+		break;
+
 	    // Check for match outside of quotes, and inside of
 	    // quotes when the start is also inside of quotes.
 	    if ((!inquote || start_in_quotes == TRUE)

src/testdir/test_cindent.vim

@@ -5526,5 +5526,85 @@ def Test_find_brace_backwards()
   bwipe!
 enddef
 
+" Brackets inside comments must not affect C indent calculation (FM_SKIPCOMM)
+def Test_cindent_comment_brackets()
+  # stray } in inline block comment must not confuse enclosing-brace search
+  new
+  setl cindent sw=4
+  var code =<< trim [CODE]
+  int foo() {
+      /* } */
+      int bar;
+  }
+  [CODE]
+  setline(1, code)
+  cursor(3, 1)
+  normal ==
+  assert_equal('    int bar;', getline(3))
+  bwipe!
+
+  # stray } in // line comment: same
+  new
+  setl cindent sw=4
+  var code2 =<< trim [CODE]
+  int foo() {
+      // }
+      int bar;
+  }
+  [CODE]
+  setline(1, code2)
+  cursor(3, 1)
+  normal ==
+  assert_equal('    int bar;', getline(3))
+  bwipe!
+
+  # stray } on continuation line inside multi-line block comment
+  new
+  setl cindent sw=4
+  var code3 =<< trim [CODE]
+  int foo() {
+      /*
+         }
+      */
+      int bar;
+  }
+  [CODE]
+  setline(1, code3)
+  cursor(5, 1)
+  normal ==
+  assert_equal('    int bar;', getline(5))
+  bwipe!
+
+  # { in inline block comment must not be treated as enclosing brace
+  new
+  setl cindent sw=4
+  var code4 =<< trim [CODE]
+  int foo() {
+      /* { */
+      int bar;
+  }
+  [CODE]
+  setline(1, code4)
+  cursor(3, 1)
+  normal ==
+  assert_equal('    int bar;', getline(3))
+  bwipe!
+
+  # ) in inline block comment must not be treated as enclosing brace
+  new
+  setl cindent sw=4
+  var code5 =<< trim [CODE]
+  some_func(arg1,
+      /* ) */ arg2,
+      arg3);
+  [CODE]
+  setline(1, code5)
+  cursor(3, 1)
+  normal ==
+  assert_equal('    arg3);', getline(3))
+  bwipe!
+
+enddef
+
 
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -729,6 +729,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    447,
 /**/
     446,
 /**/

src/vim.h

@@ -1095,7 +1095,7 @@ extern int (*dyn_libintl_wputenv)(const wchar_t *envstring);
 #define FM_BACKWARD	0x01	// search backwards
 #define FM_FORWARD	0x02	// search forwards
 #define FM_BLOCKSTOP	0x04	// stop at start/end of block
-#define FM_SKIPCOMM	0x08	// skip comments
+#define FM_SKIPCOMM	0x08	// skip comments (cursor must start outside)
 
 // Values for action argument for do_buffer() and close_buffer()
 #define DOBUF_GOTO	0	// go to specified buffer