Merge pull request #31112 from famiu/refactor/options/set_option_for

refactor(options): set option value for non-current context directly

13 files changed, 528 insertions, 552 deletions

diff --git a/src/nvim/api/deprecated.c b/src/nvim/api/deprecated.c
index d5eddb74de..47a49436ab 100644
--- a/src/nvim/api/deprecated.c
+++ b/src/nvim/api/deprecated.c
@@ -649,8 +649,8 @@ static Object get_option_from(void *from, OptScope scope, String name, Error *er
   OptVal value = NIL_OPTVAL;
 
   if (option_has_scope(opt_idx, scope)) {
-    value = get_option_value_for(opt_idx, scope == kOptScopeGlobal ? OPT_GLOBAL : OPT_LOCAL,
-                                 scope, from, err);
+    value = get_option_value_from(opt_idx, option_ctx_from(scope, from),
+                                  scope == kOptScopeGlobal ? OPT_GLOBAL : OPT_LOCAL);
     if (ERROR_SET(err)) {
       return (Object)OBJECT_INIT;
     }
@@ -701,7 +701,11 @@ static void set_option_to(uint64_t channel_id, void *to, OptScope scope, String
       : ((scope == kOptScopeGlobal) ? OPT_GLOBAL : OPT_LOCAL);
 
   WITH_SCRIPT_CONTEXT(channel_id, {
-    set_option_value_for(name.data, opt_idx, optval, opt_flags, scope, to, err);
+    const char *errmsg
+      = set_option_value_for(opt_idx, optval, option_ctx_from(scope, to), opt_flags);
+    if (errmsg) {
+      api_set_error(err, kErrorTypeException, "%s", errmsg);
+    }
   });
 }
 
diff --git a/src/nvim/api/options.c b/src/nvim/api/options.c
index 64f8a35d54..2bbbdbbe8c 100644
--- a/src/nvim/api/options.c
+++ b/src/nvim/api/options.c
@@ -157,8 +157,8 @@ Object nvim_get_option_value(String name, Dict(option) *opts, Error *err)
   void *from = NULL;
   char *filetype = NULL;
 
-  if (!validate_option_value_args(opts, name.data, &opt_idx, &opt_flags, &scope, &from,
-                                  &filetype, err)) {
+  if (!validate_option_value_args(opts, name.data, &opt_idx, &opt_flags, &scope, &from, &filetype,
+                                  err)) {
     return (Object)OBJECT_INIT;
   }
 
@@ -182,7 +182,7 @@ Object nvim_get_option_value(String name, Dict(option) *opts, Error *err)
     from = ftbuf;
   }
 
-  OptVal value = get_option_value_for(opt_idx, opt_flags, scope, from, err);
+  OptVal value = get_option_value_from(opt_idx, option_ctx_from(scope, from), opt_flags);
 
   if (ftbuf != NULL) {
     // restore curwin/curbuf and a few other things
@@ -257,7 +257,11 @@ void nvim_set_option_value(uint64_t channel_id, String name, Object value, Dict(
   });
 
   WITH_SCRIPT_CONTEXT(channel_id, {
-    set_option_value_for(name.data, opt_idx, optval, opt_flags, scope, to, err);
+    const char *errmsg
+      = set_option_value_for(opt_idx, optval, option_ctx_from(scope, to), opt_flags);
+    if (errmsg) {
+      api_set_error(err, kErrorTypeException, "%s", errmsg);
+    }
   });
 }
 
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index e3e69f4ff6..46e6b24c75 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -983,10 +983,10 @@ Buffer nvim_create_buf(Boolean listed, Boolean scratch, Error *err)
     buf_copy_options(buf, BCO_ENTER | BCO_NOHELP);
 
     if (scratch) {
-      set_option_direct_for(kOptBufhidden, STATIC_CSTR_AS_OPTVAL("hide"), OPT_LOCAL, 0,
-                            kOptScopeBuf, buf);
-      set_option_direct_for(kOptBuftype, STATIC_CSTR_AS_OPTVAL("nofile"), OPT_LOCAL, 0,
-                            kOptScopeBuf, buf);
+      set_option_direct_for(kOptBufhidden, STATIC_CSTR_AS_OPTVAL("hide"),
+                            option_ctx_from(kOptScopeBuf, buf), OPT_LOCAL, 0);
+      set_option_direct_for(kOptBuftype, STATIC_CSTR_AS_OPTVAL("nofile"),
+                            option_ctx_from(kOptScopeBuf, buf), OPT_LOCAL, 0);
       assert(buf->b_ml.ml_mfp->mf_fd < 0);  // ml_open() should not have opened swapfile already
       buf->b_p_swf = false;
       buf->b_p_ml = false;
diff --git a/src/nvim/autocmd.c b/src/nvim/autocmd.c
index eb7c8c2880..aab09de6b4 100644
--- a/src/nvim/autocmd.c
+++ b/src/nvim/autocmd.c
@@ -1251,56 +1251,82 @@ bool check_nomodeline(char **argp)
   return true;
 }
 
-/// Prepare for executing autocommands for (hidden) buffer `buf`.
-/// If the current buffer is not in any visible window, put it in a temporary
-/// floating window using an entry in `aucmd_win[]`.
-/// Set `curbuf` and `curwin` to match `buf`.
+/// Prepare for executing autocommands for (hidden) buffer `buf` on window `win`
+/// If the buffer of `win` is not `buf`, switch the buffer of `win` to `buf` temporarily.
 ///
-/// @param aco  structure to save values in
-/// @param buf  new curbuf
-void aucmd_prepbuf(aco_save_T *aco, buf_T *buf)
+/// @param  aco      Structure to save values in.
+/// @param  buf      New curbuf.
+/// @param  win      New curwin.
+void aucmd_prepbuf_win(aco_save_T *aco, buf_T *buf, win_T *win)
 {
-  win_T *win;
-  bool need_append = true;  // Append `aucmd_win` to the window list.
+  bool need_append = false;  // Append `aucmd_win` to the window list.
+  int auc_idx = -1;  // Index of aucmd_win[] to use. -1 if not using aucmd_win[].
 
-  // Find a window that is for the new buffer
-  if (buf == curbuf) {  // be quick when buf is curbuf
-    win = curwin;
-  } else {
-    win = NULL;
-    FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
-      if (wp->w_buffer == buf) {
-        win = wp;
-        break;
+  aco->save_curtab_handle = -1;
+  aco->save_buf_handle = -1;
+
+  if (win == NULL) {
+    // Window not provided. Find a window that is for the new buffer
+    if (buf == curbuf) {  // be quick when buf is curbuf
+      win = curwin;
+    } else {
+      win = NULL;
+      FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
+        if (wp->w_buffer == buf) {
+          win = wp;
+          break;
+        }
       }
     }
-  }
 
-  // Allocate a window when needed.
-  win_T *auc_win = NULL;
-  int auc_idx = AUCMD_WIN_COUNT;
-  if (win == NULL) {
-    for (auc_idx = 0; auc_idx < AUCMD_WIN_COUNT; auc_idx++) {
-      if (!aucmd_win[auc_idx].auc_win_used) {
-        break;
+    // Allocate a window when needed.
+    if (win == NULL) {
+      for (auc_idx = 0; auc_idx < AUCMD_WIN_COUNT; auc_idx++) {
+        if (!aucmd_win[auc_idx].auc_win_used) {
+          break;
+        }
+      }
+
+      if (auc_idx == AUCMD_WIN_COUNT) {
+        kv_push(aucmd_win_vec, ((aucmdwin_T){
+          .auc_win = NULL,
+          .auc_win_used = false,
+        }));
+      }
+
+      if (aucmd_win[auc_idx].auc_win == NULL) {
+        win_alloc_aucmd_win(auc_idx);
+      } else {
+        need_append = true;
       }
+      win = aucmd_win[auc_idx].auc_win;
+      aucmd_win[auc_idx].auc_win_used = true;
     }
+  } else {
+    tabpage_T *tp = win_find_tabpage(win);
 
-    if (auc_idx == AUCMD_WIN_COUNT) {
-      kv_push(aucmd_win_vec, ((aucmdwin_T){
-        .auc_win = NULL,
-        .auc_win_used = false,
-      }));
+    // If the window is in another tab page, switch to that tab page temporarily.
+    if (tp != curtab) {
+      aco->save_curtab_handle = curtab->handle;
+      unuse_tabpage(curtab);
+      use_tabpage(tp);
     }
+  }
 
-    if (aucmd_win[auc_idx].auc_win == NULL) {
-      win_alloc_aucmd_win(auc_idx);
-      need_append = false;
+  // If the buffer of the window is not the target buffer, switch to it temporarily.
+  if (win->w_buffer != buf) {
+    if (auc_idx == -1) {
+      // No need to store old buffer for aucmd_win[].
+      aco->save_buf_handle = win->w_buffer->handle;
+      win->w_buffer->b_nwindows--;
     }
-    auc_win = aucmd_win[auc_idx].auc_win;
-    aucmd_win[auc_idx].auc_win_used = true;
+
+    win->w_buffer = buf;
+    win->w_s = &buf->b_s;
+    buf->b_nwindows++;
   }
 
+  aco->use_aucmd_win_idx = auc_idx;
   aco->save_curwin_handle = curwin->handle;
   aco->save_prevwin_handle = prevwin == NULL ? 0 : prevwin->handle;
   aco->save_State = State;
@@ -1308,26 +1334,15 @@ void aucmd_prepbuf(aco_save_T *aco, buf_T *buf)
     aco->save_prompt_insert = curbuf->b_prompt_insert;
   }
 
-  if (win != NULL) {
-    // There is a window for "buf" in the current tab page, make it the
-    // curwin.  This is preferred, it has the least side effects (esp. if
-    // "buf" is curbuf).
-    aco->use_aucmd_win_idx = -1;
-    curwin = win;
-  } else {
-    // There is no window for "buf", use "auc_win".  To minimize the side
-    // effects, insert it in the current tab page.
-    // Anything related to a window (e.g., setting folds) may have
-    // unexpected results.
-    aco->use_aucmd_win_idx = auc_idx;
-    auc_win->w_buffer = buf;
-    auc_win->w_s = &buf->b_s;
-    buf->b_nwindows++;
-    win_init_empty(auc_win);  // set cursor and topline to safe values
+  if (auc_idx >= 0) {
+    // There is no window for "buf", use "win". To minimize the side effects, insert it in the
+    // current tab page. Anything related to a window (e.g., setting folds) may have unexpected
+    // results.
+    win_init_empty(win);  // Set cursor and topline to safe values.
 
-    // Make sure w_localdir, tp_localdir and globaldir are NULL to avoid a
-    // chdir() in win_enter_ext().
-    XFREE_CLEAR(auc_win->w_localdir);
+    // Make sure w_localdir, tp_localdir and globaldir are NULL to avoid a chdir() in
+    // win_enter_ext().
+    XFREE_CLEAR(win->w_localdir);
     aco->tp_localdir = curtab->tp_localdir;
     curtab->tp_localdir = NULL;
     aco->globaldir = globaldir;
@@ -1335,30 +1350,43 @@ void aucmd_prepbuf(aco_save_T *aco, buf_T *buf)
 
     block_autocmds();  // We don't want BufEnter/WinEnter autocommands.
     if (need_append) {
-      win_append(lastwin, auc_win, NULL);
-      pmap_put(int)(&window_handles, auc_win->handle, auc_win);
-      win_config_float(auc_win, auc_win->w_config);
+      win_append(lastwin, win, NULL);
+      pmap_put(int)(&window_handles, win->handle, win);
+      win_config_float(win, win->w_config);
     }
     // Prevent chdir() call in win_enter_ext(), through do_autochdir()
     const int save_acd = p_acd;
     p_acd = false;
-    // no redrawing and don't set the window title
+    // No redrawing and don't set the window title
     RedrawingDisabled++;
-    win_enter(auc_win, false);
+    win_enter(win, false);
     RedrawingDisabled--;
     p_acd = save_acd;
     unblock_autocmds();
-    curwin = auc_win;
   }
+
+  curwin = win;
   curbuf = buf;
   aco->new_curwin_handle = curwin->handle;
   set_bufref(&aco->new_curbuf, curbuf);
 
-  // disable the Visual area, the position may be invalid in another buffer
+  // Disable the Visual area, the position may be invalid in another buffer
   aco->save_VIsual_active = VIsual_active;
   VIsual_active = false;
 }
 
+/// Prepare for executing autocommands for (hidden) buffer `buf`.
+/// If the current buffer is not in any visible window, put it in a temporary
+/// floating window using an entry in `aucmd_win[]`.
+/// Set `curbuf` and `curwin` to match `buf`.
+///
+/// @param  aco  structure to save values in
+/// @param  buf  new curbuf
+void aucmd_prepbuf(aco_save_T *aco, buf_T *buf)
+{
+  aucmd_prepbuf_win(aco, buf, NULL);
+}
+
 /// Cleanup after executing autocommands for a (hidden) buffer.
 /// Restore the window as it was (if possible).
 ///
@@ -1447,6 +1475,19 @@ win_found:
       curwin->w_topfill = 0;
     }
   } else {
+    // Restore old buffer of new window if it was changed.
+    if (aco->save_buf_handle != -1) {
+      win_T *new_win = win_find_by_handle(aco->new_curwin_handle);
+      buf_T *new_win_buf = handle_get_buffer(aco->save_buf_handle);
+
+      if (new_win != NULL && new_win_buf != NULL) {
+        new_win->w_buffer->b_nwindows--;
+        new_win->w_buffer = new_win_buf;
+        new_win->w_s = &new_win_buf->b_s;
+        new_win_buf->b_nwindows++;
+      }
+    }
+
     // Restore curwin.  Use the window ID, a window may have been closed
     // and the memory re-used for another one.
     win_T *const save_curwin = win_find_by_handle(aco->save_curwin_handle);
@@ -1482,6 +1523,13 @@ win_found:
   if (VIsual_active) {
     check_pos(curbuf, &VIsual);
   }
+
+  // Switch back to the original tab page if it was switched.
+  if (aco->save_curtab_handle != -1) {
+    tabpage_T *save_curtab = handle_get_tabpage(aco->save_curtab_handle);
+    unuse_tabpage(curtab);
+    use_tabpage(save_curtab);
+  }
 }
 
 /// Execute autocommands for "event" and file name "fname".
diff --git a/src/nvim/autocmd_defs.h b/src/nvim/autocmd_defs.h
index cba947e85f..777ee7b87a 100644
--- a/src/nvim/autocmd_defs.h
+++ b/src/nvim/autocmd_defs.h
@@ -14,16 +14,18 @@
 /// Struct to save values in before executing autocommands for a buffer that is
 /// not the current buffer.
 typedef struct {
-  int use_aucmd_win_idx;          ///< index in aucmd_win[] if >= 0
-  handle_T save_curwin_handle;    ///< ID of saved curwin
-  handle_T new_curwin_handle;     ///< ID of new curwin
-  handle_T save_prevwin_handle;   ///< ID of saved prevwin
-  bufref_T new_curbuf;            ///< new curbuf
-  char *tp_localdir;              ///< saved value of tp_localdir
-  char *globaldir;                ///< saved value of globaldir
-  bool save_VIsual_active;        ///< saved VIsual_active
-  int save_State;                 ///< saved State
-  int save_prompt_insert;         ///< saved b_prompt_insert
+  int use_aucmd_win_idx;             ///< index in aucmd_win[] if >= 0
+  handle_T save_curwin_handle;       ///< ID of saved curwin
+  handle_T save_curtab_handle;       ///< ID of saved curtab. -1 if not switched.
+  handle_T new_curwin_handle;        ///< ID of new curwin
+  handle_T save_buf_handle;          ///< ID of saved buffer of new curwin. -1 if not switched.
+  handle_T save_prevwin_handle;      ///< ID of saved prevwin
+  bufref_T new_curbuf;               ///< new curbuf
+  char *tp_localdir;                 ///< saved value of tp_localdir
+  char *globaldir;                   ///< saved value of globaldir
+  bool save_VIsual_active;           ///< saved VIsual_active
+  int save_State;                    ///< saved State
+  int save_prompt_insert;            ///< saved b_prompt_insert
 } aco_save_T;
 
 typedef struct {
diff --git a/src/nvim/diff.c b/src/nvim/diff.c
index bd98a31a71..ebeb9ba088 100644
--- a/src/nvim/diff.c
+++ b/src/nvim/diff.c
@@ -1391,8 +1391,8 @@ void diff_win_options(win_T *wp, bool addbuf)
     }
     wp->w_p_fdm_save = xstrdup(wp->w_p_fdm);
   }
-  set_option_direct_for(kOptFoldmethod, STATIC_CSTR_AS_OPTVAL("diff"), OPT_LOCAL, 0,
-                        kOptScopeWin, wp);
+  set_option_direct_for(kOptFoldmethod, STATIC_CSTR_AS_OPTVAL("diff"),
+                        option_ctx_from(kOptScopeWin, wp), OPT_LOCAL, 0);
 
   if (!wp->w_p_diff) {
     wp->w_p_fen_save = wp->w_p_fen;
diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index 6f9f0f07c9..ceb3a074b4 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -5294,7 +5294,7 @@ static char *findfunc_find_file(char *findarg, size_t findarg_len, int count)
 /// Returns NULL on success and an error message on failure.
 const char *did_set_findfunc(optset_T *args)
 {
-  buf_T *buf = (buf_T *)args->os_buf;
+  buf_T *buf = args->os_ctx.buf;
   int retval;
 
   if (args->os_flags & OPT_LOCAL) {
diff --git a/src/nvim/insexpand.c b/src/nvim/insexpand.c
index 9b77644085..053d97fd64 100644
--- a/src/nvim/insexpand.c
+++ b/src/nvim/insexpand.c
@@ -2401,7 +2401,7 @@ static void copy_global_to_buflocal_cb(Callback *globcb, Callback *bufcb)
 /// lambda expression.
 const char *did_set_completefunc(optset_T *args)
 {
-  buf_T *buf = (buf_T *)args->os_buf;
+  buf_T *buf = args->os_ctx.buf;
   if (option_set_callback_func(buf->b_p_cfu, &cfu_cb) == FAIL) {
     return e_invarg;
   }
@@ -2422,7 +2422,7 @@ void set_buflocal_cfu_callback(buf_T *buf)
 /// lambda expression.
 const char *did_set_omnifunc(optset_T *args)
 {
-  buf_T *buf = (buf_T *)args->os_buf;
+  buf_T *buf = args->os_ctx.buf;
   if (option_set_callback_func(buf->b_p_ofu, &ofu_cb) == FAIL) {
     return e_invarg;
   }
@@ -2443,7 +2443,7 @@ void set_buflocal_ofu_callback(buf_T *buf)
 /// lambda expression.
 const char *did_set_thesaurusfunc(optset_T *args FUNC_ATTR_UNUSED)
 {
-  buf_T *buf = (buf_T *)args->os_buf;
+  buf_T *buf = args->os_ctx.buf;
   int retval;
 
   if (args->os_flags & OPT_LOCAL) {
diff --git a/src/nvim/option.c b/src/nvim/option.c
index 551ea0be20..2b102fe1bb 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -1324,7 +1324,8 @@ static void do_one_set_option(int opt_flags, char **argp, bool *did_show, char *
     return;
   }
 
-  *errmsg = set_option(opt_idx, newval, opt_flags, 0, false, op == OP_NONE, errbuf, errbuflen);
+  *errmsg = set_option_for(opt_idx, newval, option_ctx(), opt_flags, 0, false,
+                           op == OP_NONE, errbuf, errbuflen);
 }
 
 /// Parse 'arg' for option settings.
@@ -1844,7 +1845,7 @@ void set_option_sctx(OptIndex opt_idx, int opt_flags, sctx_T script_ctx)
 
 /// Apply the OptionSet autocommand.
 static void apply_optionset_autocmd(OptIndex opt_idx, int opt_flags, OptVal oldval, OptVal oldval_g,
-                                    OptVal oldval_l, OptVal newval, const char *errmsg)
+                                    OptVal oldval_l, OptVal newval, OptCtx ctx, const char *errmsg)
 {
   // Don't do this while starting up, failure or recursively.
   if (starting || errmsg != NULL || *get_vim_var_str(VV_OPTION_TYPE) != NUL) {
@@ -1878,14 +1879,18 @@ static void apply_optionset_autocmd(OptIndex opt_idx, int opt_flags, OptVal oldv
     set_vim_var_string(VV_OPTION_COMMAND, "modeline", -1);
     set_vim_var_tv(VV_OPTION_OLDLOCAL, &oldval_tv);
   }
-  apply_autocmds(EVENT_OPTIONSET, options[opt_idx].fullname, NULL, false, NULL);
+
+  WITH_AUCMD_CONTEXT(ctx, {
+    apply_autocmds(EVENT_OPTIONSET, options[opt_idx].fullname, NULL, false, NULL);
+  });
+
   reset_v_option_vars();
 }
 
 /// Process the updated 'arabic' option value.
 static const char *did_set_arabic(optset_T *args)
 {
-  win_T *win = (win_T *)args->os_win;
+  win_T *win = args->os_ctx.win;
   const char *errmsg = NULL;
 
   if (win->w_p_arab) {
@@ -1954,7 +1959,7 @@ static const char *did_set_autochdir(optset_T *args FUNC_ATTR_UNUSED)
 /// Process the updated 'binary' option value.
 static const char *did_set_binary(optset_T *args)
 {
-  buf_T *buf = (buf_T *)args->os_buf;
+  buf_T *buf = args->os_ctx.buf;
 
   // when 'bin' is set also set some other options
   set_options_bin((int)args->os_oldval.boolean, buf->b_p_bin, args->os_flags);
@@ -1966,7 +1971,7 @@ static const char *did_set_binary(optset_T *args)
 /// Process the updated 'buflisted' option value.
 static const char *did_set_buflisted(optset_T *args)
 {
-  buf_T *buf = (buf_T *)args->os_buf;
+  buf_T *buf = args->os_ctx.buf;
 
   // when 'buflisted' changes, trigger autocommands
   if (args->os_oldval.boolean != buf->b_p_bl) {
@@ -2000,7 +2005,7 @@ static const char *did_set_cmdheight(optset_T *args)
 /// Process the updated 'diff' option value.
 static const char *did_set_diff(optset_T *args)
 {
-  win_T *win = (win_T *)args->os_win;
+  win_T *win = args->os_ctx.win;
   // May add or remove the buffer from the list of diff buffers.
   diff_buf_adjust(win);
   if (foldmethodIsDiff(win)) {
@@ -2021,7 +2026,7 @@ static const char *did_set_eof_eol_fixeol_bomb(optset_T *args FUNC_ATTR_UNUSED)
 /// Process the updated 'equalalways' option value.
 static const char *did_set_equalalways(optset_T *args)
 {
-  win_T *win = (win_T *)args->os_win;
+  win_T *win = args->os_ctx.win;
   if (p_ea && !args->os_oldval.boolean) {
     win_equal(win, false, 0);
   }
@@ -2039,7 +2044,7 @@ static const char *did_set_foldlevel(optset_T *args FUNC_ATTR_UNUSED)
 /// Process the new 'foldminlines' option value.
 static const char *did_set_foldminlines(optset_T *args)
 {
-  win_T *win = (win_T *)args->os_win;
+  win_T *win = args->os_ctx.win;
   foldUpdateAll(win);
   return NULL;
 }
@@ -2047,7 +2052,7 @@ static const char *did_set_foldminlines(optset_T *args)
 /// Process the new 'foldnestmax' option value.
 static const char *did_set_foldnestmax(optset_T *args)
 {
-  win_T *win = (win_T *)args->os_win;
+  win_T *win = args->os_ctx.win;
   if (foldmethodIsSyntax(win) || foldmethodIsIndent(win)) {
     foldUpdateAll(win);
   }
@@ -2176,7 +2181,7 @@ static const char *did_set_lines_or_columns(optset_T *args)
 /// Process the updated 'lisp' option value.
 static const char *did_set_lisp(optset_T *args)
 {
-  buf_T *buf = (buf_T *)args->os_buf;
+  buf_T *buf = args->os_ctx.buf;
   // When 'lisp' option changes include/exclude '-' in keyword characters.
   buf_init_chartab(buf, false);          // ignore errors
   return NULL;
@@ -2194,7 +2199,7 @@ static const char *did_set_modifiable(optset_T *args FUNC_ATTR_UNUSED)
 /// Process the updated 'modified' option value.
 static const char *did_set_modified(optset_T *args)
 {
-  buf_T *buf = (buf_T *)args->os_buf;
+  buf_T *buf = args->os_ctx.buf;
   if (!args->os_newval.boolean) {
     save_file_ff(buf);  // Buffer is unchanged
   }
@@ -2206,7 +2211,7 @@ static const char *did_set_modified(optset_T *args)
 /// Process the updated 'number' or 'relativenumber' option value.
 static const char *did_set_number_relativenumber(optset_T *args)
 {
-  win_T *win = (win_T *)args->os_win;
+  win_T *win = args->os_ctx.win;
   if (*win->w_p_stc != NUL) {
     // When 'relativenumber'/'number' is changed and 'statuscolumn' is set, reset width.
     win->w_nrwidth_line_count = 0;
@@ -2218,7 +2223,7 @@ static const char *did_set_number_relativenumber(optset_T *args)
 /// Process the new 'numberwidth' option value.
 static const char *did_set_numberwidth(optset_T *args)
 {
-  win_T *win = (win_T *)args->os_win;
+  win_T *win = args->os_ctx.win;
   win->w_nrwidth_line_count = 0;  // trigger a redraw
 
   return NULL;
@@ -2356,7 +2361,7 @@ static const char *did_set_paste(optset_T *args FUNC_ATTR_UNUSED)
 /// Process the updated 'previewwindow' option value.
 static const char *did_set_previewwindow(optset_T *args)
 {
-  win_T *win = (win_T *)args->os_win;
+  win_T *win = args->os_ctx.win;
 
   if (!win->w_p_pvw) {
     return NULL;
@@ -2388,7 +2393,7 @@ static const char *did_set_pumblend(optset_T *args FUNC_ATTR_UNUSED)
 /// Process the updated 'readonly' option value.
 static const char *did_set_readonly(optset_T *args)
 {
-  buf_T *buf = (buf_T *)args->os_buf;
+  buf_T *buf = args->os_ctx.buf;
 
   // when 'readonly' is reset globally, also reset readonlymode
   if (!buf->b_p_ro && (args->os_flags & OPT_LOCAL) == 0) {
@@ -2408,7 +2413,7 @@ static const char *did_set_readonly(optset_T *args)
 /// Process the new 'scrollback' option value.
 static const char *did_set_scrollback(optset_T *args)
 {
-  buf_T *buf = (buf_T *)args->os_buf;
+  buf_T *buf = args->os_ctx.buf;
   OptInt old_value = args->os_oldval.number;
   OptInt value = args->os_newval.number;
 
@@ -2422,7 +2427,7 @@ static const char *did_set_scrollback(optset_T *args)
 /// Process the updated 'scrollbind' option value.
 static const char *did_set_scrollbind(optset_T *args)
 {
-  win_T *win = (win_T *)args->os_win;
+  win_T *win = args->os_ctx.win;
 
   // when 'scrollbind' is set: snapshot the current position to avoid a jump
   // at the end of normal_cmd()
@@ -2459,8 +2464,8 @@ static const char *did_set_shellslash(optset_T *args FUNC_ATTR_UNUSED)
 /// Process the new 'shiftwidth' or the 'tabstop' option value.
 static const char *did_set_shiftwidth_tabstop(optset_T *args)
 {
-  buf_T *buf = (buf_T *)args->os_buf;
-  win_T *win = (win_T *)args->os_win;
+  buf_T *buf = args->os_ctx.buf;
+  win_T *win = args->os_ctx.win;
   OptInt *pp = (OptInt *)args->os_varp;
 
   if (foldmethodIsIndent(win)) {
@@ -2486,7 +2491,7 @@ static const char *did_set_showtabline(optset_T *args FUNC_ATTR_UNUSED)
 /// Process the updated 'smoothscroll' option value.
 static const char *did_set_smoothscroll(optset_T *args FUNC_ATTR_UNUSED)
 {
-  win_T *win = (win_T *)args->os_win;
+  win_T *win = args->os_ctx.win;
   if (!win->w_p_sms) {
     win->w_skipcol = 0;
   }
@@ -2497,7 +2502,7 @@ static const char *did_set_smoothscroll(optset_T *args FUNC_ATTR_UNUSED)
 /// Process the updated 'spell' option value.
 static const char *did_set_spell(optset_T *args)
 {
-  win_T *win = (win_T *)args->os_win;
+  win_T *win = args->os_ctx.win;
   if (win->w_p_spell) {
     return parse_spelllang(win);
   }
@@ -2508,7 +2513,7 @@ static const char *did_set_spell(optset_T *args)
 /// Process the updated 'swapfile' option value.
 static const char *did_set_swapfile(optset_T *args)
 {
-  buf_T *buf = (buf_T *)args->os_buf;
+  buf_T *buf = args->os_ctx.buf;
   // when 'swf' is set, create swapfile, when reset remove swapfile
   if (buf->b_p_swf && p_uc) {
     ml_open_file(buf);                     // create the swap file
@@ -2553,7 +2558,7 @@ static const char *did_set_titlelen(optset_T *args)
 /// Process the updated 'undofile' option value.
 static const char *did_set_undofile(optset_T *args)
 {
-  buf_T *buf = (buf_T *)args->os_buf;
+  buf_T *buf = args->os_ctx.buf;
 
   // Only take action when the option was set.
   if (!buf->b_p_udf && !p_udf) {
@@ -2604,7 +2609,7 @@ const char *did_set_buflocal_undolevels(buf_T *buf, OptInt value, OptInt old_val
 /// Process the new 'undolevels' option value.
 static const char *did_set_undolevels(optset_T *args)
 {
-  buf_T *buf = (buf_T *)args->os_buf;
+  buf_T *buf = args->os_ctx.buf;
   OptInt *pp = (OptInt *)args->os_varp;
 
   if (pp == &p_ul) {                  // global 'undolevels'
@@ -2645,7 +2650,7 @@ static const char *did_set_wildchar(optset_T *args)
 /// Process the new 'winblend' option value.
 static const char *did_set_winblend(optset_T *args)
 {
-  win_T *win = (win_T *)args->os_win;
+  win_T *win = args->os_ctx.win;
   OptInt old_value = args->os_oldval.number;
   OptInt value = args->os_newval.number;
 
@@ -2694,7 +2699,7 @@ static const char *did_set_winwidth(optset_T *args)
 /// Process the updated 'wrap' option value.
 static const char *did_set_wrap(optset_T *args)
 {
-  win_T *win = (win_T *)args->os_win;
+  win_T *win = args->os_ctx.win;
   // Set w_leftcol or w_skipcol to zero.
   if (win->w_p_wrap) {
     win->w_leftcol = 0;
@@ -3143,12 +3148,6 @@ static OptValType option_get_type(const OptIndex opt_idx)
 OptVal optval_from_varp(OptIndex opt_idx, void *varp)
   FUNC_ATTR_NONNULL_ARG(2)
 {
-  // Special case: 'modified' is b_changed, but we also want to consider it set when 'ff' or 'fenc'
-  // changed.
-  if ((int *)varp == &curbuf->b_changed) {
-    return BOOLEAN_OPTVAL(curbufIsChanged());
-  }
-
   if (option_is_multitype(opt_idx)) {
     // Multitype options are stored as OptVal.
     return *(OptVal *)varp;
@@ -3381,21 +3380,37 @@ uint32_t get_option_flags(OptIndex opt_idx)
 /// Gets the value for an option.
 ///
 /// @param  opt_idx    Option index in options[] table.
+/// @param  ctx        Context to get the option value from.
 /// @param  opt_flags  Option flags (can be OPT_LOCAL, OPT_GLOBAL or a combination).
 ///
 /// @return [allocated] Option value. Returns NIL_OPTVAL for invalid option index.
-OptVal get_option_value(OptIndex opt_idx, int opt_flags)
+OptVal get_option_value_from(OptIndex opt_idx, OptCtx ctx, int opt_flags)
 {
   if (opt_idx == kOptInvalid) {  // option not in the options[] table.
     return NIL_OPTVAL;
   }
 
-  vimoption_T *opt = &options[opt_idx];
-  void *varp = get_varp_scope(opt, opt_flags);
+  // Special case: 'modified' is b_changed, but we also want to consider it set when 'ff' or 'fenc'
+  // changed.
+  if (opt_idx == kOptModified) {
+    return BOOLEAN_OPTVAL(bufIsChanged(ctx.buf));
+  }
 
+  void * const varp = get_varp_scope_from(&options[opt_idx], opt_flags, ctx);
   return optval_copy(optval_from_varp(opt_idx, varp));
 }
 
+/// Gets the value for an option in the current context.
+///
+/// @param  opt_idx  Option index in options[] table.
+/// @param  opt_flags  Option flags (can be OPT_LOCAL, OPT_GLOBAL or a combination).
+///
+/// @return [allocated] Option value. Returns NIL_OPTVAL for invalid option index.
+OptVal get_option_value(OptIndex opt_idx, int opt_flags)
+{
+  return get_option_value_from(opt_idx, option_ctx(), opt_flags);
+}
+
 /// Return information for option at 'opt_idx'
 vimoption_T *get_option(OptIndex opt_idx)
 {
@@ -3464,6 +3479,8 @@ static bool is_option_local_value_unset(OptIndex opt_idx)
 /// @param       opt_idx         Index in options[] table. Must not be kOptInvalid.
 /// @param[in]   varp            Option variable pointer, cannot be NULL.
 /// @param       old_value       Old option value.
+/// @param       new_value       New option value.
+/// @param       ctx             Context in which the option is set.
 /// @param       opt_flags       Option flags (can be OPT_LOCAL, OPT_GLOBAL or a combination).
 /// @param       set_sid         Script ID. Special values:
 ///                                0: Use current script ID.
@@ -3475,8 +3492,9 @@ static bool is_option_local_value_unset(OptIndex opt_idx)
 ///
 /// @return  NULL on success, an untranslated error message on error.
 static const char *did_set_option(OptIndex opt_idx, void *varp, OptVal old_value, OptVal new_value,
-                                  int opt_flags, scid_T set_sid, const bool direct,
-                                  const bool value_replaced, char *errbuf, size_t errbuflen)
+                                  OptCtx ctx, int opt_flags, scid_T set_sid, const bool direct,
+                                  const bool value_replaced, char *errbuf,  // NOLINT(readability-non-const-parameter)
+                                  size_t errbuflen)
 {
   vimoption_T *opt = &options[opt_idx];
   const char *errmsg = NULL;
@@ -3495,8 +3513,7 @@ static const char *did_set_option(OptIndex opt_idx, void *varp, OptVal old_value
     .os_restore_chartab = false,
     .os_errbuf = errbuf,
     .os_errbuflen = errbuflen,
-    .os_buf = curbuf,
-    .os_win = curwin
+    .os_ctx = ctx,
   };
 
   if (direct) {
@@ -3533,7 +3550,7 @@ static const char *did_set_option(OptIndex opt_idx, void *varp, OptVal old_value
     set_option_varp(opt_idx, varp, old_value, true);
     // When resetting some values, need to act on it.
     if (restore_chartab) {
-      buf_init_chartab(curbuf, true);
+      buf_init_chartab(ctx.buf, true);
     }
 
     return errmsg;
@@ -3564,12 +3581,12 @@ static const char *did_set_option(OptIndex opt_idx, void *varp, OptVal old_value
     if (option_is_global_local(opt_idx)) {
       // Global option with local value set to use global value.
       // Free the local value and clear it.
-      void *varp_local = get_varp_scope(opt, OPT_LOCAL);
+      void *varp_local = get_varp_scope_from(opt, OPT_LOCAL, ctx);
       OptVal local_unset_value = get_option_unset_value(opt_idx);
       set_option_varp(opt_idx, varp_local, optval_copy(local_unset_value), true);
     } else {
       // May set global value for local option.
-      void *varp_global = get_varp_scope(opt, OPT_GLOBAL);
+      void *varp_global = get_varp_scope_from(opt, OPT_GLOBAL, ctx);
       set_option_varp(opt_idx, varp_global, optval_copy(new_value), true);
     }
   }
@@ -3580,17 +3597,23 @@ static const char *did_set_option(OptIndex opt_idx, void *varp, OptVal old_value
   }
 
   // Trigger the autocommand only after setting the flags.
-  if (varp == &curbuf->b_p_syn) {
-    do_syntax_autocmd(curbuf, value_changed);
-  } else if (varp == &curbuf->b_p_ft) {
+  if (varp == &ctx.buf->b_p_syn) {
+    WITH_AUCMD_CONTEXT(ctx, {
+      do_syntax_autocmd(ctx.buf, value_changed);
+    });
+  } else if (varp == &ctx.buf->b_p_ft) {
     // 'filetype' is set, trigger the FileType autocommand
     // Skip this when called from a modeline
     // Force autocmd when the filetype was changed
     if (!(opt_flags & OPT_MODELINE) || value_changed) {
-      do_filetype_autocmd(curbuf, value_changed);
+      WITH_AUCMD_CONTEXT(ctx, {
+        do_filetype_autocmd(ctx.buf, value_changed);
+      });
     }
-  } else if (varp == &curwin->w_s->b_p_spl) {
-    do_spelllang_source(curwin);
+  } else if (varp == &ctx.win->w_s->b_p_spl) {
+    WITH_AUCMD_CONTEXT(ctx, {
+      do_spelllang_source(ctx.win);
+    });
   }
 
   // In case 'ruler' or 'showcmd' or 'columns' or 'ls' changed.
@@ -3598,25 +3621,25 @@ static const char *did_set_option(OptIndex opt_idx, void *varp, OptVal old_value
 
   if (varp == &p_mouse) {
     setmouse();  // in case 'mouse' changed
-  } else if ((varp == &p_flp || varp == &(curbuf->b_p_flp)) && curwin->w_briopt_list) {
+  } else if ((varp == &p_flp || varp == &(ctx.buf->b_p_flp)) && ctx.win->w_briopt_list) {
     // Changing Formatlistpattern when briopt includes the list setting:
     // redraw
     redraw_all_later(UPD_NOT_VALID);
-  } else if (varp == &p_wbr || varp == &(curwin->w_p_wbr)) {
+  } else if (varp == &p_wbr || varp == &(ctx.win->w_p_wbr)) {
     // add / remove window bars for 'winbar'
     set_winbar(true);
   }
 
-  if (curwin->w_curswant !