Merge pull request #19419 from vigoux/extmark_spell

Co-authored-by: Lewis Russell <lewis6991@gmail.com>
Co-authored-by: Björn Linse <bjorn.linse@gmail.com>

runtime/doc/api.txt

@@ -2646,6 +2646,8 @@ nvim_buf_set_extmark({buffer}, {ns_id}, {line}, {col}, {*opts})
                     When a character is supplied it is used as |:syn-cchar|.
                     "hl_group" is used as highlight for the cchar if provided,
                     otherwise it defaults to |hl-Conceal|.
+                  • spell: boolean indicating that spell checking should be
+                    performed within this extmark
                   • ui_watched: boolean that indicates the mark should be
                     drawn by a UI. When set, the UI will receive win_extmark
                     events. Note: the mark is positioned by virt_text
@@ -2677,7 +2679,7 @@ nvim_get_namespaces()                                  *nvim_get_namespaces()*
         dict that maps from names to namespace ids.
 
                                               *nvim_set_decoration_provider()*
-nvim_set_decoration_provider({ns_id}, {opts})
+nvim_set_decoration_provider({ns_id}, {*opts})
     Set or change decoration provider for a namespace
 
     This is a very general purpose interface for having lua callbacks being
@@ -2709,7 +2711,7 @@ nvim_set_decoration_provider({ns_id}, {opts})
 
     Parameters: ~
         {ns_id}  Namespace id from |nvim_create_namespace()|
-        {opts}   Callbacks invoked during redraw:
+        {opts}   Table of callbacks:
                  • on_start: called first on each screen redraw ["start",
                    tick]
                  • on_buf: called for each buffer being redrawn (before window

runtime/doc/options.txt

@@ -5871,10 +5871,14 @@ A jump table for the options with a short description can be found at |Q_op|.
 'spelloptions' 'spo'	string	(default "")
 			local to buffer
 	A comma-separated list of options for spell checking:
-	   camel	When a word is CamelCased, assume "Cased" is a
+	camel		When a word is CamelCased, assume "Cased" is a
 			separate word: every upper-case character in a word
 			that comes after a lower case character indicates the
 			start of a new word.
+	noplainbuffer	Only spellcheck a buffer when 'syntax' is enabled, or
+			or when extmarks are set within the buffer. Only
+			designated regions of the buffer are spellchecked in
+			this case.
 
 						*'spellsuggest'* *'sps'*
 'spellsuggest' 'sps'	string	(default "best")

runtime/lua/vim/treesitter/highlighter.lua

@@ -97,6 +97,7 @@ function TSHighlighter.new(tree, opts)
   if vim.g.syntax_on ~= 1 then
     vim.api.nvim_command('runtime! syntax/synload.vim')
   end
+  vim.bo[self.bufnr].spelloptions = 'noplainbuffer'
 
   self.tree:parse()
 
@@ -156,7 +157,7 @@ function TSHighlighter:get_query(lang)
 end
 
 ---@private
-local function on_line_impl(self, buf, line)
+local function on_line_impl(self, buf, line, spell)
   self.tree:for_each_tree(function(tstree, tree)
     if not tstree then
       return
@@ -193,7 +194,9 @@ local function on_line_impl(self, buf, line)
       local start_row, start_col, end_row, end_col = node:range()
       local hl = highlighter_query.hl_cache[capture]
 
-      if hl and end_row >= line then
+      local is_spell = highlighter_query:query().captures[capture] == 'spell'
+
+      if hl and end_row >= line and (not spell or is_spell) then
         a.nvim_buf_set_extmark(buf, ns, start_row, start_col, {
           end_line = end_row,
           end_col = end_col,
@@ -201,6 +204,7 @@ local function on_line_impl(self, buf, line)
           ephemeral = true,
           priority = tonumber(metadata.priority) or 100, -- Low but leaves room below
           conceal = metadata.conceal,
+          spell = is_spell,
         })
       end
       if start_row > line then
@@ -217,7 +221,21 @@ function TSHighlighter._on_line(_, _win, buf, line, _)
     return
   end
 
-  on_line_impl(self, buf, line)
+  on_line_impl(self, buf, line, false)
+end
+
+---@private
+function TSHighlighter._on_spell_nav(_, _, buf, srow, _, erow, _)
+  local self = TSHighlighter.active[buf]
+  if not self then
+    return
+  end
+
+  self:reset_highlight_state()
+
+  for row = srow, erow do
+    on_line_impl(self, buf, row, true)
+  end
 end
 
 ---@private
@@ -244,6 +262,7 @@ a.nvim_set_decoration_provider(ns, {
   on_buf = TSHighlighter._on_buf,
   on_win = TSHighlighter._on_win,
   on_line = TSHighlighter._on_line,
+  _on_spell_nav = TSHighlighter._on_spell_nav,
 })
 
 return TSHighlighter

runtime/queries/c/highlights.scm

@@ -101,6 +101,7 @@
 [ "(" ")" "[" "]" "{" "}"] @punctuation.bracket
 
 (string_literal) @string
+(string_literal) @spell
 (system_lib_string) @string
 
 (null) @constant.builtin
@@ -148,6 +149,7 @@
 
 
 (comment) @comment
+(comment) @spell
 
 ;; Parameters
 (parameter_declaration

runtime/queries/lua/highlights.scm

@@ -181,12 +181,14 @@
 ;; Others
 
 (comment) @comment
+(comment) @spell
 
 (hash_bang_line) @comment
 
 (number) @number
 
 (string) @string
+(string) @spell
 
 ;; Error
 (ERROR) @error

runtime/queries/vim/highlights.scm

@@ -162,9 +162,11 @@
 ;; Literals
 
 (string_literal) @string
+(string_literal) @spell
 (integer_literal) @number
 (float_literal) @float
 (comment) @comment
+(comment) @spell
 (pattern) @string.special
 (pattern_multi) @string.regex
 (filename) @string

src/nvim/api/extmark.c

@@ -473,6 +473,8 @@ Array nvim_buf_get_extmarks(Buffer buffer, Integer ns_id, Object start, Object e
 ///                   When a character is supplied it is used as |:syn-cchar|.
 ///                   "hl_group" is used as highlight for the cchar if provided,
 ///                   otherwise it defaults to |hl-Conceal|.
+///               - spell: boolean indicating that spell checking should be
+///                   performed within this extmark
 ///               - ui_watched: boolean that indicates the mark should be drawn
 ///                   by a UI. When set, the UI will receive win_extmark events.
 ///                   Note: the mark is positioned by virt_text attributes. Can be
@@ -719,6 +721,11 @@ Integer nvim_buf_set_extmark(Buffer buffer, Integer ns_id, Integer line, Integer
   bool ephemeral = false;
   OPTION_TO_BOOL(ephemeral, ephemeral, false);
 
+  OPTION_TO_BOOL(decor.spell, spell, false);
+  if (decor.spell) {
+    has_decor = true;
+  }
+
   OPTION_TO_BOOL(decor.ui_watched, ui_watched, false);
   if (decor.ui_watched) {
     has_decor = true;
@@ -972,20 +979,21 @@ void nvim_buf_clear_namespace(Buffer buffer, Integer ns_id, Integer line_start,
 /// for the moment.
 ///
 /// @param ns_id  Namespace id from |nvim_create_namespace()|
-/// @param opts   Callbacks invoked during redraw:
+/// @param opts  Table of callbacks:
 ///             - on_start: called first on each screen redraw
 ///                 ["start", tick]
-///             - on_buf: called for each buffer being redrawn (before window
+///             - on_buf: called for each buffer being redrawn (before
-///                 callbacks)
+///                 window callbacks)
 ///                 ["buf", bufnr, tick]
-///             - on_win: called when starting to redraw a specific window.
+///             - on_win: called when starting to redraw a
+///                 specific window.
 ///                 ["win", winid, bufnr, topline, botline_guess]
-///             - on_line: called for each buffer line being redrawn. (The
+///             - on_line: called for each buffer line being redrawn.
-///                 interaction with fold lines is subject to change)
+///                 (The interaction with fold lines is subject to change)
 ///                 ["win", winid, bufnr, row]
 ///             - on_end: called at the end of a redraw cycle
 ///                 ["end", tick]
-void nvim_set_decoration_provider(Integer ns_id, DictionaryOf(LuaRef) opts, Error *err)
+void nvim_set_decoration_provider(Integer ns_id, Dict(set_decoration_provider) *opts, Error *err)
   FUNC_API_SINCE(7) FUNC_API_LUA_ONLY
 {
   DecorProvider *p = get_decor_provider((NS)ns_id, true);
@@ -997,37 +1005,32 @@ void nvim_set_decoration_provider(Integer ns_id, DictionaryOf(LuaRef) opts, Erro
 
   struct {
     const char *name;
+    Object *source;
     LuaRef *dest;
   } cbs[] = {
-    { "on_start", &p->redraw_start },
+    { "on_start", &opts->on_start, &p->redraw_start },
-    { "on_buf", &p->redraw_buf },
+    { "on_buf", &opts->on_buf, &p->redraw_buf },
-    { "on_win", &p->redraw_win },
+    { "on_win", &opts->on_win, &p->redraw_win },
-    { "on_line", &p->redraw_line },
+    { "on_line", &opts->on_line, &p->redraw_line },
-    { "on_end", &p->redraw_end },
+    { "on_end", &opts->on_end, &p->redraw_end },
-    { "_on_hl_def", &p->hl_def },
+    { "_on_hl_def", &opts->_on_hl_def, &p->hl_def },
-    { NULL, NULL },
+    { "_on_spell_nav", &opts->_on_spell_nav, &p->spell_nav },
+    { NULL, NULL, NULL },
   };
 
-  for (size_t i = 0; i < opts.size; i++) {
+  for (size_t i = 0; cbs[i].source && cbs[i].dest && cbs[i].name; i++) {
-    String k = opts.items[i].key;
+    Object *v = cbs[i].source;
-    Object *v = &opts.items[i].value;
+    if (v->type == kObjectTypeNil) {
-    size_t j;
+      continue;
-    for (j = 0; cbs[j].name && cbs[j].dest; j++) {
-      if (strequal(cbs[j].name, k.data)) {
-        if (v->type != kObjectTypeLuaRef) {
-          api_set_error(err, kErrorTypeValidation,
-                        "%s is not a function", cbs[j].name);
-          goto error;
-        }
-        *(cbs[j].dest) = v->data.luaref;
-        v->data.luaref = LUA_NOREF;
-        break;
-      }
     }
-    if (!cbs[j].name) {
+
-      api_set_error(err, kErrorTypeValidation, "unexpected key: %s", k.data);
+    if (v->type != kObjectTypeLuaRef) {
+      api_set_error(err, kErrorTypeValidation,
+                    "%s is not a function", cbs[i].name);
       goto error;
     }
+    *(cbs[i].dest) = v->data.luaref;
+    v->data.luaref = LUA_NOREF;
   }
 
   p->active = true;

src/nvim/api/keysets.lua

@@ -2,6 +2,15 @@ return {
   context = {
     "types";
   };
+  set_decoration_provider = {
+    "on_start";
+    "on_buf";
+    "on_win";
+    "on_line";
+    "on_end";
+    "_on_hl_def";
+    "_on_spell_nav";
+  };
   set_extmark = {
     "id";
     "end_line";
@@ -28,6 +37,7 @@ return {
     "line_hl_group";
     "cursorline_hl_group";
     "conceal";
+    "spell";
     "ui_watched";
   };
   keymap = {

src/nvim/buffer_defs.h

@@ -462,6 +462,9 @@ typedef struct {
   char *b_p_spf;              // 'spellfile'
   char *b_p_spl;              // 'spelllang'
   char *b_p_spo;              // 'spelloptions'
+#define SPO_CAMEL  0x1
+#define SPO_NPBUFFER 0x2
+  unsigned b_p_spo_flags;      // 'spelloptions' flags
   int b_cjk;                  // all CJK letters as OK
   uint8_t b_syn_chartab[32];  // syntax iskeyword option
   char *b_syn_isk;            // iskeyword option

src/nvim/decoration.c

@@ -69,7 +69,7 @@ void bufhl_add_hl_pos_offset(buf_T *buf, int src_id, int hl_id, lpos_T pos_start
 void decor_redraw(buf_T *buf, int row1, int row2, Decoration *decor)
 {
   if (row2 >= row1) {
-    if (!decor || decor->hl_id || decor_has_sign(decor) || decor->conceal) {
+    if (!decor || decor->hl_id || decor_has_sign(decor) || decor->conceal || decor->spell) {
       redraw_buf_range_later(buf, row1 + 1, row2 + 1);
     }
   }
@@ -116,6 +116,11 @@ void decor_free(Decoration *decor)
   }
 }
 
+void decor_state_free(DecorState *state)
+{
+  xfree(state->active.items);
+}
+
 void clear_virttext(VirtText *text)
 {
   for (size_t i = 0; i < kv_size(*text); i++) {
@@ -306,6 +311,7 @@ next_mark:
   bool conceal = 0;
   int conceal_char = 0;
   int conceal_attr = 0;
+  bool spell = false;
 
   for (size_t i = 0; i < kv_size(state->active); i++) {
     DecorRange item = kv_A(state->active, i);
@@ -339,6 +345,9 @@ next_mark:
         conceal_attr = item.attr_id;
       }
     }
+    if (active && item.decor.spell) {
+      spell = true;
+    }
     if ((item.start_row == state->row && item.start_col <= col)
         && decor_virt_pos(item.decor)
         && item.decor.virt_text_pos == kVTOverlay && item.win_col == -1) {
@@ -355,6 +364,7 @@ next_mark:
   state->conceal = conceal;
   state->conceal_char = conceal_char;
   state->conceal_attr = conceal_attr;
+  state->spell = spell;
   return attr;
 }
 

src/nvim/decoration.h

@@ -46,6 +46,7 @@ struct Decoration {
   bool hl_eol;
   bool virt_lines_above;
   bool conceal;
+  bool spell;
   // TODO(bfredl): style, etc
   DecorPriority priority;
   int col;  // fixed col value, like win_col
@@ -61,8 +62,8 @@ struct Decoration {
   bool ui_watched;  // watched for win_extmark
 };
 #define DECORATION_INIT { KV_INITIAL_VALUE, KV_INITIAL_VALUE, 0, kVTEndOfLine, \
-                          kHlModeUnknown, false, false, false, false, DECOR_PRIORITY_BASE, \
+                          kHlModeUnknown, false, false, false, false, false, \
-                          0, 0, NULL, 0, 0, 0, 0, 0, false }
+                          DECOR_PRIORITY_BASE, 0, 0, NULL, 0, 0, 0, 0, 0, false }
 
 typedef struct {
   int start_row;
@@ -90,6 +91,8 @@ typedef struct {
   bool conceal;
   int conceal_char;
   int conceal_attr;
+
+  bool spell;
 } DecorState;
 
 EXTERN DecorState decor_state INIT(= { 0 });

src/nvim/decoration_provider.c

@@ -7,6 +7,7 @@
 #include "nvim/decoration.h"
 #include "nvim/decoration_provider.h"
 #include "nvim/highlight.h"
+#include "nvim/lib/kvec.h"
 #include "nvim/lua/executor.h"
 
 static kvec_t(DecorProvider) decor_providers = KV_INITIAL_VALUE;
@@ -14,7 +15,7 @@ static kvec_t(DecorProvider) decor_providers = KV_INITIAL_VALUE;
 #define DECORATION_PROVIDER_INIT(ns_id) (DecorProvider) \
   { ns_id, false, LUA_NOREF, LUA_NOREF, \
     LUA_NOREF, LUA_NOREF, LUA_NOREF, \
-    LUA_NOREF, -1, false }
+    LUA_NOREF, -1, false, false }
 
 static bool decor_provider_invoke(NS ns_id, const char *name, LuaRef ref, Array args,
                                   bool default_true, char **perr)
@@ -47,11 +48,33 @@ static bool decor_provider_invoke(NS ns_id, const char *name, LuaRef ref, Array
   return false;
 }
 
+void decor_providers_invoke_spell(win_T *wp, int start_row, int start_col, int end_row, int end_col,
+                                  char **err)
+{
+  for (size_t i = 0; i < kv_size(decor_providers); i++) {
+    DecorProvider *p = &kv_A(decor_providers, i);
+    if (!p->active) {
+      continue;
+    }
+
+    if (p->spell_nav != LUA_NOREF) {
+      MAXSIZE_TEMP_ARRAY(args, 6);
+      ADD_C(args, INTEGER_OBJ(wp->handle));
+      ADD_C(args, INTEGER_OBJ(wp->w_buffer->handle));
+      ADD_C(args, INTEGER_OBJ(start_row));
+      ADD_C(args, INTEGER_OBJ(start_col));
+      ADD_C(args, INTEGER_OBJ(end_row));
+      ADD_C(args, INTEGER_OBJ(end_col));
+      decor_provider_invoke(p->ns_id, "spell", p->spell_nav, args, true, err);
+    }
+  }
+}
+
 /// For each provider invoke the 'start' callback
 ///
 /// @param[out] providers Decoration providers
 /// @param[out] err       Provider err
-void decor_providers_start(DecorProviders *providers, int type, char **err)
+void decor_providers_start(DecorProviders *providers, char **err)
 {
   kvi_init(*providers);
 
@@ -65,7 +88,6 @@ void decor_providers_start(DecorProviders *providers, int type, char **err)
     if (p->redraw_start != LUA_NOREF) {
       MAXSIZE_TEMP_ARRAY(args, 2);
       ADD_C(args, INTEGER_OBJ((int)display_tick));
-      ADD_C(args, INTEGER_OBJ(type));
       active = decor_provider_invoke(p->ns_id, "start", p->redraw_start, args, true, err);
     } else {
       active = true;
@@ -116,8 +138,8 @@ void decor_providers_invoke_win(win_T *wp, DecorProviders *providers,
 /// @param      row       Row to invoke line callback for
 /// @param[out] has_decor Set when at least one provider invokes a line callback
 /// @param[out] err       Provider error
-void providers_invoke_line(win_T *wp, DecorProviders *providers, int row, bool *has_decor,
+void decor_providers_invoke_line(win_T *wp, DecorProviders *providers, int row, bool *has_decor,
-                           char **err)
+                                 char **err)
 {
   for (size_t k = 0; k < kv_size(*providers); k++) {
     DecorProvider *p = kv_A(*providers, k);
@@ -215,6 +237,7 @@ void decor_provider_clear(DecorProvider *p)
   NLUA_CLEAR_REF(p->redraw_win);
   NLUA_CLEAR_REF(p->redraw_line);
   NLUA_CLEAR_REF(p->redraw_end);
+  NLUA_CLEAR_REF(p->spell_nav);
   p->active = false;
 }
 

src/nvim/decoration_provider.h

@@ -12,6 +12,7 @@ typedef struct {
   LuaRef redraw_line;
   LuaRef redraw_end;
   LuaRef hl_def;
+  LuaRef spell_nav;
   int hl_valid;
   bool hl_cached;
 } DecorProvider;

src/nvim/drawline.c

@@ -11,9 +11,11 @@
 
 #include "nvim/arabic.h"
 #include "nvim/buffer.h"
+#include "nvim/buffer_defs.h"
 #include "nvim/charset.h"
 #include "nvim/cursor.h"
 #include "nvim/cursor_shape.h"
+#include "nvim/decoration.h"
 #include "nvim/diff.h"
 #include "nvim/drawline.h"
 #include "nvim/fold.h"
@@ -654,7 +656,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
 
     has_decor = decor_redraw_line(buf, lnum - 1, &decor_state);
 
-    providers_invoke_line(wp, providers, lnum - 1, &has_decor, provider_err);
+    decor_providers_invoke_line(wp, providers, lnum - 1, &has_decor, provider_err);
 
     if (*provider_err) {
       provider_err_virt_text(lnum, *provider_err);
@@ -1646,7 +1648,8 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
       ptr++;
 
       if (extra_check) {
-        bool can_spell = true;
+        bool no_plain_buffer = (wp->w_s->b_p_spo_flags & SPO_NPBUFFER) != 0;
+        bool can_spell = !no_plain_buffer;
 
         // Get syntax attribute, unless still at the start of the line
         // (double-wide char that doesn't fit).
@@ -1698,6 +1701,29 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
           char_attr = 0;
         }
 
+        if (has_decor && v > 0) {
+          bool selected = (area_active || (area_highlighting && noinvcur
+                                           && (colnr_T)vcol == wp->w_virtcol));
+          int extmark_attr = decor_redraw_col(wp->w_buffer, (colnr_T)v - 1, off,
+                                              selected, &decor_state);
+          if (extmark_attr != 0) {
+            if (!attr_pri) {
+              char_attr = hl_combine_attr(char_attr, extmark_attr);
+            } else {
+              char_attr = hl_combine_attr(extmark_attr, char_attr);
+            }
+          }
+
+          decor_conceal = decor_state.conceal;
+          if (decor_conceal && decor_state.conceal_char) {
+            decor_conceal = 2;  // really??
+          }
+
+          if (decor_state.spell) {
+            can_spell = true;
+          }
+        }
+
         // Check spelling (unless at the end of the line).
         // Only do this when there is no syntax highlighting, the
         // @Spell cluster is not used or the current syntax item
@@ -1706,9 +1732,9 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
         if (has_spell && v >= word_end && v > cur_checked_col) {
           spell_attr = 0;
           if (!attr_pri) {
-            char_attr = syntax_attr;
+            char_attr = hl_combine_attr(char_attr, syntax_attr);
           }
-          if (c != 0 && (!has_syntax || can_spell)) {
+          if (c != 0 && ((!has_syntax && !no_plain_buffer) || can_spell)) {
             char_u *prev_ptr;
             char_u *p;
             int len;
@@ -1781,25 +1807,6 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
           char_attr = hl_combine_attr(term_attrs[vcol], char_attr);
         }
 
-        if (has_decor && v > 0) {
-          bool selected = (area_active || (area_highlighting && noinvcur
-                                           && (colnr_T)vcol == wp->w_virtcol));
-          int extmark_attr = decor_redraw_col(wp->w_buffer, (colnr_T)v - 1, off,
-                                              selected, &decor_state);
-          if (extmark_attr != 0) {
-            if (!attr_pri) {
-              char_attr = hl_combine_attr(char_attr, extmark_attr);
-            } else {
-              char_attr = hl_combine_attr(extmark_attr, char_attr);
-            }
-          }
-
-          decor_conceal = decor_state.conceal;
-          if (decor_conceal && decor_state.conceal_char) {
-            decor_conceal = 2;  // really??
-          }
-        }
-
         // Found last space before word: check for line break.
         if (wp->w_p_lbr && c0 == c && vim_isbreak(c)
             && !vim_isbreak((int)(*ptr))) {

src/nvim/drawscreen.c

@@ -539,7 +539,7 @@ int update_screen(int type)
   ui_comp_set_screen_valid(true);
 
   DecorProviders providers;
-  decor_providers_start(&providers, type, &provider_err);
+  decor_providers_start(&providers, &provider_err);
 
   // "start" callback could have changed highlights for global elements
   if (win_check_ns_hl(NULL)) {

src/nvim/extmark.c

@@ -70,7 +70,8 @@ void extmark_set(buf_T *buf, uint32_t ns_id, uint32_t *idp, int row, colnr_T col
         || kv_size(decor->virt_lines)
         || decor->conceal
         || decor_has_sign(decor)
-        || decor->ui_watched) {
+        || decor->ui_watched
+        || decor->spell) {
       decor_full = true;
       decor = xmemdup(decor, sizeof *decor);
     }

src/nvim/option_defs.h

@@ -731,6 +731,7 @@ EXTERN char *p_spc;             ///< 'spellcapcheck'
 EXTERN char *p_spf;             ///< 'spellfile'
 EXTERN char *p_spl;             ///< 'spelllang'
 EXTERN char *p_spo;             // 'spelloptions'
+EXTERN unsigned int spo_flags;
 EXTERN char *p_sps;             // 'spellsuggest'
 EXTERN int p_spr;               // 'splitright'
 EXTERN int p_sol;               // 'startofline'

src/nvim/options.lua

@@ -2355,6 +2355,7 @@ return {
       secure=true,
       expand=true,
       varname='p_spo',
+      redraw={'current_buffer'},
       defaults={if_true=""}
     },
     {

src/nvim/optionstr.c

@@ -107,6 +107,7 @@ static char *(p_fdc_values[]) = { "auto", "auto:1", "auto:2", "auto:3", "auto:4"
                                   "auto:6", "auto:7", "auto:8", "auto:9", "0", "1", "2", "3", "4",
                                   "5", "6", "7", "8", "9", NULL };
 static char *(p_cb_values[]) = { "unnamed", "unnamedplus", NULL };
+static char *(p_spo_values[]) = { "camel", "noplainbuffer", NULL };
 static char *(p_icm_values[]) = { "nosplit", "split", NULL };
 static char *(p_jop_values[]) = { "stack", "view", NULL };
 static char *(p_tpf_values[]) = { "BS", "HT", "FF", "ESC", "DEL", "C0", "C1", NULL };
@@ -1125,7 +1126,8 @@ char *did_set_string_option(int opt_idx, char **varp, char *oldval, char *errbuf
     // When 'spellcapcheck' is set compile the regexp program.
     errmsg = compile_cap_prog(curwin->w_s);
   } else if (varp == &(curwin->w_s->b_p_spo)) {  // 'spelloptions'
-    if (**varp != NUL && STRCMP("camel", *varp) != 0) {
+    if (opt_strings_flags(curwin->w_s->b_p_spo, p_spo_values, &(curwin->w_s->b_p_spo_flags),
+                          true) != OK) {
       errmsg = e_invarg;
     }
   } else if (varp == &p_sps) {  // 'spellsuggest'

src/nvim/spell.c

@@ -71,6 +71,7 @@
 #include "nvim/change.h"          // for changed_bytes
 #include "nvim/charset.h"         // for skipwhite, getwhitecols, skipbin
 #include "nvim/cursor.h"          // for get_cursor_line_ptr
+#include "nvim/decoration.h"
 #include "nvim/drawscreen.h"      // for NOT_VALID, redraw_later
 #include "nvim/eval/typval.h"     // for semsg
 #include "nvim/ex_cmds.h"         // for do_sub_msg
@@ -220,7 +221,7 @@ size_t spell_check(win_T *wp, char_u *ptr, hlf_T *attrp, int *capcol, bool docou
   size_t nrlen = 0;              // found a number first
   size_t wrongcaplen = 0;
   bool count_word = docount;
-  bool use_camel_case = *wp->w_s->b_p_spo != NUL;
+  bool use_camel_case = (wp->w_s->b_p_spo_flags & SPO_CAMEL) != 0;
   bool camel_case = false;
 
   // A word never starts at a space or a control character. Return quickly
@@ -1198,6 +1199,24 @@ bool no_spell_checking(win_T *wp)
   return false;
 }
 
+static void decor_spell_nav_start(win_T *wp)
+{
+  decor_state = (DecorState){ 0 };
+  decor_redraw_reset(wp->w_buffer, &decor_state);
+}
+
+static bool decor_spell_nav_col(win_T *wp, linenr_T lnum, linenr_T *decor_lnum, int col,
+                                char **decor_error)
+{
+  if (*decor_lnum != lnum) {
+    decor_providers_invoke_spell(wp, lnum - 1, col, lnum - 1, -1, decor_error);
+    decor_redraw_line(wp->w_buffer, lnum - 1, &decor_state);
+    *decor_lnum = lnum;
+  }
+  decor_redraw_col(wp->w_buffer, col, col, false, &decor_state);
+  return decor_state.spell;
+}
+
 /// Moves to the next spell error.
 /// "curline" is false for "[s", "]s", "[S" and "]S".
 /// "curline" is true to find word under/after cursor in the same line.
@@ -1216,11 +1235,11 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
   hlf_T attr = HLF_COUNT;
   size_t len;
   int has_syntax = syntax_present(wp);
-  int col;
+  colnr_T col;
   char_u *buf = NULL;
   size_t buflen = 0;
   int skip = 0;
-  int capcol = -1;
+  colnr_T capcol = -1;
   bool found_one = false;
   bool wrapped = false;
 
@@ -1228,6 +1247,8 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
     return 0;
   }
 
+  size_t ret = 0;
+
   // Start looking for bad word at the start of the line, because we can't
   // start halfway through a word, we don't know where it starts or ends.
   //
@@ -1240,6 +1261,19 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
   linenr_T lnum = wp->w_cursor.lnum;
   clearpos(&found_pos);
 
+  char *decor_error = NULL;
+  // Ephemeral extmarks are currently stored in the global decor_state.
+  // When looking for spell errors, we need to:
+  //  - temporarily reset decor_state
+  //  - run the _on_spell_nav decor callback for each line we look at
+  //  - detect if any spell marks are present
+  //  - restore decor_state to the value saved here.
+  // TODO(lewis6991): un-globalize decor_state and allow ephemeral marks to be stored into a
+  // temporary DecorState.
+  DecorState saved_decor_start = decor_state;
+  linenr_T decor_lnum = -1;
+  decor_spell_nav_start(wp);
+
   while (!got_int) {
     char_u *line = ml_get_buf(wp->w_buffer, lnum, false);
 
@@ -1258,10 +1292,10 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
 
     // For checking first word with a capital skip white space.
     if (capcol == 0) {
-      capcol = (int)getwhitecols((char *)line);
+      capcol = (colnr_T)getwhitecols((char *)line);
     } else if (curline && wp == curwin) {
       // For spellbadword(): check if first word needs a capital.
-      col = (int)getwhitecols((char *)line);
+      col = (colnr_T)getwhitecols((char *)line);
       if (check_need_cap(lnum, col)) {
         capcol = col;
       }
@@ -1308,33 +1342,37 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
               || ((colnr_T)(curline
                             ? p - buf + (ptrdiff_t)len
                             : p - buf) > wp->w_cursor.col)) {
-            bool can_spell;
+            col = (colnr_T)(p - buf);
-            if (has_syntax) {
+
-              col = (int)(p - buf);
+            bool can_spell = (wp->w_s->b_p_spo_flags & SPO_NPBUFFER) == 0;
-              (void)syn_get_id(wp, lnum, (colnr_T)col,
+
-                               false, &can_spell, false);
+            if (!can_spell) {
-              if (!can_spell) {
+              can_spell = decor_spell_nav_col(wp, lnum, &decor_lnum, col, &decor_error);
-                attr = HLF_COUNT;
+            }
-              }
+
-            } else {
+            if (!can_spell && has_syntax) {
-              can_spell = true;
+              (void)syn_get_id(wp, lnum, col, false, &can_spell, false);
+            }
+
+            if (!can_spell) {
+              attr = HLF_COUNT;
             }
 
             if (can_spell) {
               found_one = true;
               found_pos = (pos_T) {
                 .lnum = lnum,
-                .col = (int)(p - buf),
+                .col = col,
                 .coladd = 0
               };
               if (dir == FORWARD) {
                 // No need to search further.
                 wp->w_cursor = found_pos;
-                xfree(buf);
                 if (attrp != NULL) {
                   *attrp = attr;
                 }
-                return len;
+                ret = len;
+                goto theend;
               } else if (curline) {
                 // Insert mode completion: put cursor after
                 // the bad word.
@@ -1358,8 +1396,8 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
     if (dir == BACKWARD && found_pos.lnum != 0) {
       // Use the last match in the line (before the cursor).
       wp->w_cursor = found_pos;
-      xfree(buf);
+      ret = found_len;
-      return found_len;
+      goto theend;
     }
 
     if (curline) {
@@ -1429,8 +1467,12 @@ size_t spell_move_to(win_T *wp, int dir, bool allwords, bool curline, hlf_T *att
     line_breakcheck();
   }
 
+theend:
+  decor_state_free(&decor_state);
+  xfree(decor_error);
+  decor_state = saved_decor_start;
   xfree(buf);
-  return 0;
+  return ret;
 }
 
 // For spell checking: concatenate the start of the following line "line" into

test/functional/ui/decorations_spec.lua

@@ -31,6 +31,8 @@ describe('decorations providers', function()
       [12] = {foreground = tonumber('0x990000')};
       [13] = {background = Screen.colors.LightBlue};
       [14] = {background = Screen.colors.WebGray, foreground = Screen.colors.DarkBlue};
+      [15] = {special = Screen.colors.Blue1, undercurl = true},
+      [16] = {special = Screen.colors.Red, undercurl = true},
     }
   end)
 
@@ -56,7 +58,7 @@ describe('decorations providers', function()
       a.nvim_set_decoration_provider(_G.ns1, {
         on_start = on_do; on_buf = on_do;
         on_win = on_do; on_line = on_do;
-        on_end = on_do;
+        on_end = on_do; _on_spell_nav = on_do;
       })
       return _G.ns1
     ]])
@@ -95,7 +97,7 @@ describe('decorations providers', function()
                                               |
     ]]}
     check_trace {
-      { "start", 4, 40 };
+      { "start", 4 };
       { "win", 1000, 1, 0, 8 };
       { "line", 1000, 1, 0 };
       { "line", 1000, 1, 1 };
@@ -119,7 +121,7 @@ describe('decorations providers', function()
                                               |
     ]]}
     check_trace {
-      { "start", 5, 10 };
+      { "start", 5 };
       { "buf", 1 };
       { "win", 1000, 1, 0, 8 };
       { "line", 1000, 1, 6 };
@@ -156,6 +158,84 @@ describe('decorations providers', function()
     ]]}
   end)
 
+  it('can indicate spellchecked points', function()
+    exec [[
+    set spell
+    set spelloptions=noplainbuffer
+    syntax off
+    ]]
+
+    insert [[
+    I am well written text.
+    i am not capitalized.
+    I am a speling mistakke.
+    ]]
+
+    setup_provider [[
+      local ns = a.nvim_create_namespace "spell"
+      beamtrace = {}
+      local function on_do(kind, ...)
+        if kind == 'win' or kind == 'spell' then
+          a.nvim_buf_set_extmark(0, ns, 0, 0, { end_row = 2, end_col = 23, spell = true, ephemeral = true })
+        end
+        table.insert(beamtrace, {kind, ...})
+      end
+    ]]
+
+    check_trace {
+      { "start", 5 };
+      { "win", 1000, 1, 0, 5 };
+      { "line", 1000, 1, 0 };
+      { "line", 1000, 1, 1 };
+      { "line", 1000, 1, 2 };
+      { "line", 1000, 1, 3 };
+      { "end", 5 };
+    }
+
+    feed "gg0"
+
+    screen:expect{grid=[[
+    ^I am well written text.                 |
+    {15:i} am not capitalized.                   |
+    I am a {16:speling} {16:mistakke}.                |
+                                            |
+    {1:~                                       }|
+    {1:~                                       }|
+    {1:~                                       }|
+                                            |
+    ]]}
+
+    feed "]s"
+    check_trace {
+      { "spell", 1000, 1, 1, 0, 1, -1 };
+    }
+    screen:expect{grid=[[
+    I am well written text.                 |
+    {15:^i} am not capitalized.                   |
+    I am a {16:speling} {16:mistakke}.                |
+                                            |
+    {1:~                                       }|
+    {1:~                                       }|
+    {1:~                                       }|
+                                            |
+    ]]}
+
+    feed "]s"
+    check_trace {
+      { "spell", 1000, 1, 2, 7, 2, -1 };
+    }
+    screen:expect{grid=[[
+    I am well written text.                 |
+    {15:i} am not capitalized.                   |
+    I am a {16:^speling} {16:mistakke}.                |
+                                            |
+    {1:~                                       }|
+    {1:~                                       }|
+    {1:~                                       }|
+                                            |
+    ]]}
+  end)
+
   it('can predefine highlights', function()
     screen:try_resize(40, 16)
     insert(mulholland)