fix(statuscolumn): fix crashes and clang/PVS warnings (#21725)

6 files changed, 57 insertions, 29 deletions

diff --git a/src/nvim/buffer_defs.h b/src/nvim/buffer_defs.h
index 40249c2f9d..c794b88229 100644
--- a/src/nvim/buffer_defs.h
+++ b/src/nvim/buffer_defs.h
@@ -1419,20 +1419,20 @@ struct window_S {
 typedef struct statuscol statuscol_T;
 
 struct statuscol {
-  int width;                       // width of the status column
-  int cur_attr;                    // current attributes in text
-  int num_attr;                    // attributes used for line number
-  int fold_attr;                   // attributes used for fold column
-  int sign_attr[SIGN_SHOW_MAX];    // attributes used for signs
-  int truncate;                    // truncated width
-  bool draw;                       // draw statuscolumn or not
-  char fold_text[10];              // text in fold column (%C)
-  char *sign_text[SIGN_SHOW_MAX];  // text in sign column (%s)
-  char text[MAXPATHL];             // text in status column
-  char *textp;                     // current position in text
-  size_t text_len;                 // length of text
-  stl_hlrec_t *hlrec;              // highlight groups
-  stl_hlrec_t *hlrecp;             // current highlight group
+  int width;                           ///< width of the status column
+  int cur_attr;                        ///< current attributes in text
+  int num_attr;                        ///< attributes used for line number
+  int fold_attr;                       ///< attributes used for fold column
+  int sign_attr[SIGN_SHOW_MAX + 1];    ///< attributes used for signs
+  int truncate;                        ///< truncated width
+  bool draw;                           ///< draw statuscolumn or not
+  char fold_text[10];                  ///< text in fold column (%C)
+  char *sign_text[SIGN_SHOW_MAX + 1];  ///< text in sign column (%s)
+  char text[MAXPATHL];                 ///< text in status column
+  char *textp;                         ///< current position in text
+  char *text_end;                      ///< end of text (the NUL byte)
+  stl_hlrec_t *hlrec;                  ///< highlight groups
+  stl_hlrec_t *hlrecp;                 ///< current highlight group
 };
 
 /// Macros defined in Vim, but not in Neovim
diff --git a/src/nvim/drawline.c b/src/nvim/drawline.c
index 23ef7400b7..b1cdfe209b 100644
--- a/src/nvim/drawline.c
+++ b/src/nvim/drawline.c
@@ -450,14 +450,13 @@ static void get_statuscol_str(win_T *wp, linenr_T lnum, int row, int startrow, i
   stcp->textp = stcp->text;
   stcp->hlrecp = stcp->hlrec;
   stcp->cur_attr = stcp->num_attr;
-  stcp->text_len = strlen(stcp->text);
+  stcp->text_end = stcp->text + strlen(stcp->text);
 
   int fill = stcp->width - width;
   if (fill > 0) {
     // Fill up with ' '
-    memset(&stcp->text[stcp->text_len], ' ', (size_t)fill);
-    stcp->text_len += (size_t)fill;
-    stcp->text[stcp->text_len] = NUL;
+    memset(stcp->text_end, ' ', (size_t)fill);
+    *(stcp->text_end += fill) = NUL;
   }
 }
 
@@ -476,10 +475,9 @@ static void get_statuscol_display_info(LineDrawState *draw_state, int *char_attr
     *draw_state = WL_STC;
     *char_attr = stcp->cur_attr;
     *pp_extra = stcp->textp;
-    *n_extrap = stcp->hlrecp->start ? (int)(stcp->hlrecp->start - stcp->textp)
-                                    : (int)strlen(*pp_extra);
+    *n_extrap = (int)((stcp->hlrecp->start ? stcp->hlrecp->start : stcp->text_end) - stcp->textp);
     // Prepare for next highlight section if not yet at the end
-    if (stcp->textp + *n_extrap < stcp->text + stcp->text_len) {
+    if (stcp->textp + *n_extrap < stcp->text_end) {
       int hl = stcp->hlrecp->userhl;
       stcp->textp = stcp->hlrecp->start;
       stcp->cur_attr = hl < 0 ? syn_id2attr(-stcp->hlrecp->userhl)
@@ -488,7 +486,7 @@ static void get_statuscol_display_info(LineDrawState *draw_state, int *char_attr
       *draw_state = WL_STC - 1;
     }
     // Skip over empty highlight sections
-  } while (*n_extrap == 0 && stcp->textp < stcp->text + stcp->text_len);
+  } while (*n_extrap == 0 && stcp->textp < stcp->text_end);
 }
 
 /// Return true if CursorLineNr highlight is to be used for the number column.
@@ -1328,7 +1326,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
         draw_state = WL_STC;
         // Draw the 'statuscolumn' if option is set.
         if (statuscol.draw) {
-          if (statuscol.text_len == 0) {
+          if (statuscol.textp == NULL) {
             get_statuscol_str(wp, lnum, row, startrow, filler_lines, cul_attr,
                               sign_num_attr, sattrs, foldinfo, extra, &statuscol);
             if (wp->w_redr_statuscol) {
@@ -2823,7 +2821,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
       if (statuscol.draw) {
         if (row == startrow + 1 || row == startrow + filler_lines) {
           // Re-evaluate 'statuscolumn' for the first wrapped row and non filler line
-          statuscol.text_len = 0;
+          statuscol.textp = NULL;
         } else {  // Otherwise just reset the text/hlrec pointers
           statuscol.textp = statuscol.text;
           statuscol.hlrecp = statuscol.hlrec;
diff --git a/src/nvim/mouse.c b/src/nvim/mouse.c
index 88103d1888..ee8c553cd5 100644
--- a/src/nvim/mouse.c
+++ b/src/nvim/mouse.c
@@ -1110,7 +1110,7 @@ retnomove:
     ? wp->w_winbar_height != 0
     : false;
 
-  on_statuscol = grid == (col < win_col_off(wp))
+  on_statuscol = (grid == (col < win_col_off(wp)))
     ? *wp->w_p_stc != NUL
     : false;
 
diff --git a/src/nvim/statusline.c b/src/nvim/statusline.c
index 7d8394e1b4..6857bef810 100644
--- a/src/nvim/statusline.c
+++ b/src/nvim/statusline.c
@@ -1502,7 +1502,7 @@ int build_stl_str_hl(win_T *wp, char *out, size_t outlen, char *fmt, char *opt_n
 
     case STL_LINE:
       // Overload %l with v:lnum for 'statuscolumn'
-      num = strcmp(opt_name, "statuscolumn") == 0 ? get_vim_var_nr(VV_LNUM)
+      num = opt_name != NULL && strcmp(opt_name, "statuscolumn") == 0 ? get_vim_var_nr(VV_LNUM)
             : (wp->w_buffer->b_ml.ml_flags & ML_EMPTY) ? 0L : (long)(wp->w_cursor.lnum);
       break;
 
@@ -1602,7 +1602,7 @@ int build_stl_str_hl(win_T *wp, char *out, size_t outlen, char *fmt, char *opt_n
     case STL_ROFLAG:
     case STL_ROFLAG_ALT:
       // Overload %r with v:relnum for 'statuscolumn'
-      if (strcmp(opt_name, "statuscolumn") == 0) {
+      if (opt_name != NULL && strcmp(opt_name, "statuscolumn") == 0) {
         num = get_vim_var_nr(VV_RELNUM);
       } else {
         itemisflag = true;
@@ -1628,7 +1628,7 @@ int build_stl_str_hl(win_T *wp, char *out, size_t outlen, char *fmt, char *opt_n
 
       bool fold = opt == STL_FOLDCOL;
       *buf_tmp = NUL;
-      for (int i = 0; i <= 9; i++) {
+      for (int i = 0; i <= SIGN_SHOW_MAX; i++) {
         char *p = fold ? stcp->fold_text : stcp->sign_text[i];
         if ((!p || !*p) && *buf_tmp == NUL) {
           break;
diff --git a/test/functional/api/vim_spec.lua b/test/functional/api/vim_spec.lua
index 98bfb83dbd..aa2f46bb59 100644
--- a/test/functional/api/vim_spec.lua
+++ b/test/functional/api/vim_spec.lua
@@ -3126,7 +3126,12 @@ describe('API', function()
       eq('E539: Illegal character <}>',
          pcall_err(meths.eval_statusline, '%{%}', {}))
     end)
-    it('supports %S item', function()
+    it('supports various items', function()
+      eq({ str = '0', width = 1 },
+         meths.eval_statusline('%l', { maxwidth = 5 }))
+      command('set readonly')
+      eq({ str = '[RO]', width = 4 },
+         meths.eval_statusline('%r', { maxwidth = 5 }))
       local screen = Screen.new(80, 24)
       screen:attach()
       command('set showcmd')
diff --git a/test/functional/ui/statuscolumn_spec.lua b/test/functional/ui/statuscolumn_spec.lua
index cdc2cb8746..912c139ae4 100644
--- a/test/functional/ui/statuscolumn_spec.lua
+++ b/test/functional/ui/statuscolumn_spec.lua
@@ -293,6 +293,31 @@ describe('statuscolumn', function()
       {2: }{1:  │     }aaaaaa                                      |
                                                            |
     ]])
+    -- Up to 9 signs in a line
+    command('set signcolumn=auto:9 foldcolumn=auto')
+    command('sign place 5 line=6 name=piet1 buffer=1')
+    command('sign place 6 line=6 name=piet2 buffer=1')
+    command('sign place 7 line=6 name=piet1 buffer=1')
+    command('sign place 8 line=6 name=piet2 buffer=1')
+    command('sign place 9 line=6 name=piet1 buffer=1')
+    command('sign place 10 line=6 name=piet2 buffer=1')
+    command('sign place 11 line=6 name=piet1 buffer=1')
+    screen:expect([[
+      {2: }{1: 4│>>                 }aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa|
+      {2: }{1:  │                   }aaaaaaaaaaaaaaaaaaaa          |
+      {2: }{1: 3│}{0:>!}{1:                 }aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa|
+      {2: }{1:  │                   }aaaaaaaaaaaaaaaaaaaa          |
+      {2: }{1: 2│>>}{0:>!}{1:>>}{0:>!}{1:>>}{0:>!}{1:>>}{0:>!}{1:>> }aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa|
+      {2: }{1:  │                   }aaaaaaaaaaaaaaaaaaaa          |
+      {2: }{1: 1│                   }aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa|
+      {2: }{1:  │                   }aaaaaaaaaaaaaaaaaaaa          |
+      {2:+}{1: 0│                   }{3:^+--  1 line: aaaaaaaaaaaaaaaaa}|
+      {2: }{1: 1│                   }aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa|
+      {2: }{1:  │                   }aaaaaaaaaaaaaaaaaaaa          |
+      {2: }{1: 2│                   }aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa|
+      {2: }{1:  │                   }aaaaaaaaaaaaaaaaaaaa          |
+                                                           |
+    ]])
   end)
 
   it('works with \'statuscolumn\' clicks', function()