feat(api): add nvim_get_option_value

9 files changed, 192 insertions, 120 deletions

diff --git a/runtime/lua/vim/_meta.lua b/runtime/lua/vim/_meta.lua
index a3d5f64630..280222e28a 100644
--- a/runtime/lua/vim/_meta.lua
+++ b/runtime/lua/vim/_meta.lua
@@ -133,107 +133,18 @@ do -- window option accessor
   vim.wo = new_win_opt_accessor(nil)
 end
 
---[[
-Local window setter
-
-buffer options: does not get copied when split
-  nvim_set_option(buf_opt, value) -> sets the default for NEW buffers
-    this sets the hidden global default for buffer options
-
-  nvim_buf_set_option(...) -> sets the local value for the buffer
-
-  set opt=value, does BOTH global default AND buffer local value
-  setlocal opt=value, does ONLY buffer local value
-
-window options: gets copied
-  does not need to call nvim_set_option because nobody knows what the heck this does⸮
-  We call it anyway for more readable code.
-
-
-    Command                 global value       local value
-      :set option=value         set             set
- :setlocal option=value          -              set
-:setglobal option=value         set              -
---]]
-local function set_scoped_option(k, v, set_type)
-  local info = options_info[k]
-
-  -- Don't let people do setlocal with global options.
-  --    That is a feature that doesn't make sense.
-  if set_type == SET_TYPES.LOCAL and is_global_option(info) then
-    error(string.format("Unable to setlocal option: '%s', which is a global option.", k))
-  end
-
-  -- Only `setlocal` skips setting the default/global value
-  --    This will more-or-less noop for window options, but that's OK
-  if set_type ~= SET_TYPES.LOCAL then
-    a.nvim_set_option(k, v)
-  end
-
-  if is_window_option(info) then
-    if set_type ~= SET_TYPES.GLOBAL then
-      a.nvim_win_set_option(0, k, v)
-    end
-  elseif is_buffer_option(info) then
-    if set_type == SET_TYPES.LOCAL
-        or (set_type == SET_TYPES.SET and not info.global_local) then
-      a.nvim_buf_set_option(0, k, v)
-    end
-  end
-end
-
---[[
-Local window getter
-
-    Command                 global value       local value
-      :set option?               -               display
- :setlocal option?               -               display
-:setglobal option?              display             -
---]]
-local function get_scoped_option(k, set_type)
-  local info = assert(options_info[k], "Must be a valid option: " .. tostring(k))
-
-  if set_type == SET_TYPES.GLOBAL or is_global_option(info) then
-    return a.nvim_get_option(k)
-  end
-
-  if is_buffer_option(info) then
-    local was_set, value = pcall(a.nvim_buf_get_option, 0, k)
-    if was_set then return value end
-
-    if info.global_local then
-      return a.nvim_get_option(k)
-    end
-
-    error("buf_get: This should not be able to happen, given my understanding of options // " .. k)
-  end
-
-  if is_window_option(info) then
-    local ok, value = pcall(a.nvim_win_get_option, 0, k)
-    if ok then
-      return value
-    end
-
-    local global_ok, global_val = pcall(a.nvim_get_option, k)
-    if global_ok then
-      return global_val
-    end
-
-    error("win_get: This should never happen. File an issue and tag @tjdevries")
-  end
-
-  error("This fallback case should not be possible. " .. k)
-end
-
 -- vim global option
 --  this ONLY sets the global option. like `setglobal`
-vim.go = make_meta_accessor(a.nvim_get_option, a.nvim_set_option)
+vim.go = make_meta_accessor(
+  function(k) return a.nvim_get_option_value(k, {scope = "global"}) end,
+  function(k, v) return a.nvim_set_option_value(k, v, {scope = "global"}) end
+)
 
 -- vim `set` style options.
 --  it has no additional metamethod magic.
 vim.o = make_meta_accessor(
-  function(k) return get_scoped_option(k, SET_TYPES.SET) end,
-  function(k, v) return set_scoped_option(k, v, SET_TYPES.SET) end
+  function(k) return a.nvim_get_option_value(k, {}) end,
+  function(k, v) return a.nvim_set_option_value(k, v, {}) end
 )
 
 ---@brief [[
@@ -389,6 +300,10 @@ local convert_value_to_vim = (function()
   }
 
   return function(name, info, value)
+    if value == nil then
+      return vim.NIL
+    end
+
     local option_type = get_option_type(name, info)
     assert_valid_value(name, value, valid_types[option_type])
 
@@ -671,15 +586,19 @@ local create_option_metatable = function(set_type)
     }, option_mt)
   end
 
-  -- TODO(tjdevries): consider supporting `nil` for set to remove the local option.
-  --                  vim.cmd [[set option<]]
+  local scope
+  if set_type == SET_TYPES.GLOBAL then
+    scope = "global"
+  elseif set_type == SET_TYPES.LOCAL then
+    scope = "local"
+  end
 
   option_mt = {
     -- To set a value, instead use:
     --  opt[my_option] = value
     _set = function(self)
       local value = convert_value_to_vim(self._name, self._info, self._value)
-      set_scoped_option(self._name, value, set_type)
+      a.nvim_set_option_value(self._name, value, {scope = scope})
 
       return self
     end,
@@ -716,7 +635,7 @@ local create_option_metatable = function(set_type)
 
   set_mt = {
     __index = function(_, k)
-      return make_option(k, get_scoped_option(k, set_type))
+      return make_option(k, a.nvim_get_option_value(k, {scope = scope}))
     end,
 
     __newindex = function(_, k, v)
diff --git a/src/nvim/api/keysets.lua b/src/nvim/api/keysets.lua
index 144c252687..e956a54dbc 100644
--- a/src/nvim/api/keysets.lua
+++ b/src/nvim/api/keysets.lua
@@ -58,5 +58,8 @@ return {
     "highlights";
     "use_tabline";
   };
+  option = {
+    "scope";
+  };
 }
 
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 3103905819..36179b1fab 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -642,7 +642,7 @@ void nvim_set_vvar(String name, Object value, Error *err)
   dict_set_var(&vimvardict, name, value, false, false, err);
 }
 
-/// Gets an option value string.
+/// Gets the global value of an option.
 ///
 /// @param name     Option name
 /// @param[out] err Error details, if any
@@ -653,6 +653,115 @@ Object nvim_get_option(String name, Error *err)
   return get_option_from(NULL, SREQ_GLOBAL, name, err);
 }
 
+/// Gets the value of an option. The behavior of this function matches that of
+/// |:set|: the local value of an option is returned if it exists; otherwise,
+/// the global value is returned. Local values always correspond to the current
+/// buffer or window. To get a buffer-local or window-local option for a
+/// specific buffer or window, use |nvim_buf_get_option()| or
+/// |nvim_win_get_option()|.
+///
+/// @param name      Option name
+/// @param opts      Optional parameters
+///                  - scope: One of 'global' or 'local'. Analagous to
+///                  |:setglobal| and |:setlocal|, respectively.
+/// @param[out] err  Error details, if any
+/// @return          Option value
+Object nvim_get_option_value(String name, Dict(option) *opts, Error *err)
+  FUNC_API_SINCE(9)
+{
+  Object rv = OBJECT_INIT;
+
+  int scope = 0;
+  if (opts->scope.type == kObjectTypeString) {
+    if (!strcmp(opts->scope.data.string.data, "local")) {
+      scope = OPT_LOCAL;
+    } else if (!strcmp(opts->scope.data.string.data, "global")) {
+      scope = OPT_GLOBAL;
+    } else {
+      api_set_error(err, kErrorTypeValidation, "invalid scope: must be 'local' or 'global'");
+      goto end;
+    }
+  } else if (HAS_KEY(opts->scope)) {
+    api_set_error(err, kErrorTypeValidation, "invalid value for key: scope");
+    goto end;
+  }
+
+  long numval = 0;
+  char *stringval = NULL;
+  switch (get_option_value(name.data, &numval, (char_u **)&stringval, scope)) {
+  case 0:
+    rv = STRING_OBJ(cstr_as_string(stringval));
+    break;
+  case 1:
+    rv = INTEGER_OBJ(numval);
+    break;
+  case 2:
+    rv = BOOLEAN_OBJ(!!numval);
+    break;
+  default:
+    api_set_error(err, kErrorTypeValidation, "unknown option '%s'", name.data);
+    goto end;
+  }
+
+end:
+  return rv;
+}
+
+/// Sets the value of an option. The behavior of this function matches that of
+/// |:set|: for global-local options, both the global and local value are set
+/// unless otherwise specified with {scope}.
+///
+/// @param name      Option name
+/// @param value     New option value
+/// @param opts      Optional parameters
+///                  - scope: One of 'global' or 'local'. Analagous to
+///                  |:setglobal| and |:setlocal|, respectively.
+/// @param[out] err  Error details, if any
+void nvim_set_option_value(String name, Object value, Dict(option) *opts, Error *err)
+  FUNC_API_SINCE(9)
+{
+  int scope = 0;
+  if (opts->scope.type == kObjectTypeString) {
+    if (!strcmp(opts->scope.data.string.data, "local")) {
+      scope = OPT_LOCAL;
+    } else if (!strcmp(opts->scope.data.string.data, "global")) {
+      scope = OPT_GLOBAL;
+    } else {
+      api_set_error(err, kErrorTypeValidation, "invalid scope: must be 'local' or 'global'");
+      return;
+    }
+  } else if (HAS_KEY(opts->scope)) {
+    api_set_error(err, kErrorTypeValidation, "invalid value for key: scope");
+    return;
+  }
+
+  long numval = 0;
+  char *stringval = NULL;
+
+  switch (value.type) {
+  case kObjectTypeInteger:
+    numval = value.data.integer;
+    break;
+  case kObjectTypeBoolean:
+    numval = value.data.boolean ? 1 : 0;
+    break;
+  case kObjectTypeString:
+    stringval = value.data.string.data;
+    break;
+  case kObjectTypeNil:
+    // Do nothing
+    break;
+  default:
+    api_set_error(err, kErrorTypeValidation, "invalid value for option");
+    return;
+  }
+
+  char *e = set_option_value(name.data, numval, stringval, scope);
+  if (e) {
+    api_set_error(err, kErrorTypeException, "%s", e);
+  }
+}
+
 /// Gets the option information for all options.
 ///
 /// The dictionary has the full option names as keys and option metadata
@@ -694,7 +803,7 @@ Dictionary nvim_get_option_info(String name, Error *err)
   return get_vimoption(name, err);
 }
 
-/// Sets an option value.
+/// Sets the global value of an option.
 ///
 /// @param channel_id
 /// @param name     Option name
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index 29740283c6..2faae08fc8 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -4828,7 +4828,7 @@ int get_option_tv(const char **const arg, typval_T *const rettv, const bool eval
     } else if (opt_type == -1) {      // hidden number option
       rettv->v_type = VAR_NUMBER;
       rettv->vval.v_number = 0;
-    } else if (opt_type == 1) {       // number option
+    } else if (opt_type == 1 || opt_type == 2) {  // number or boolean option
       rettv->v_type = VAR_NUMBER;
       rettv->vval.v_number = numval;
     } else {                          // string option
diff --git a/src/nvim/option.c b/src/nvim/option.c
index 45e2032b35..ee5f62d826 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -4771,7 +4771,8 @@ static int findoption(const char *const arg)
 /// @param stringval  NULL when only checking existence
 ///
 /// @returns:
-/// Number or Toggle option: 1, *numval gets value.
+///           Toggle option: 2, *numval gets value.
+///           Number option: 1, *numval gets value.
 ///           String option: 0, *stringval gets allocated string.
 /// Hidden Number or Toggle option: -1.
 ///           hidden String option: -2.
@@ -4804,16 +4805,18 @@ int get_option_value(const char *name, long *numval, char_u **stringval, int opt
   }
   if (options[opt_idx].flags & P_NUM) {
     *numval = *(long *)varp;
+    return 1;
+  }
+
+  // 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) {
+    *numval = curbufIsChanged();
   } else {
-    // 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) {
-      *numval = curbufIsChanged();
-    } else {
-      *numval = (long)*(int *)varp;  // NOLINT(whitespace/cast)
-    }
+    *numval = (long)*(int *)varp;  // NOLINT(whitespace/cast)
   }
-  return 1;
+
+  return 2;
 }
 
 // Returns the option attributes and its value. Unlike the above function it
@@ -4909,7 +4912,7 @@ int get_option_value_strict(char *name, int64_t *numval, char **stringval, int o
         // only getting a pointer, no need to use aucmd_prepbuf()
         curbuf = (buf_T *)from;
         curwin->w_buffer = curbuf;
-        varp = get_varp(p);
+        varp = get_varp_scope(p, OPT_LOCAL);
         curbuf = save_curbuf;
         curwin->w_buffer = curbuf;
       }
@@ -4917,7 +4920,7 @@ int get_option_value_strict(char *name, int64_t *numval, char **stringval, int o
       win_T *save_curwin = curwin;
       curwin = (win_T *)from;
       curbuf = curwin->w_buffer;
-      varp = get_varp(p);
+      varp = get_varp_scope(p, OPT_LOCAL);
       curwin = save_curwin;
       curbuf = curwin->w_buffer;
     }
diff --git a/test/functional/api/buffer_spec.lua b/test/functional/api/buffer_spec.lua
index a0c97804b7..688f3abba5 100644
--- a/test/functional/api/buffer_spec.lua
+++ b/test/functional/api/buffer_spec.lua
@@ -629,6 +629,13 @@ describe('api/buf', function()
       -- Doesn't change the global value
       eq([[^\s*#\s*define]], nvim('get_option', 'define'))
     end)
+
+    it('returns values for unset local options', function()
+      -- 'undolevels' is only set to its "unset" value when a new buffer is
+      -- created
+      command('enew')
+      eq(-123456, curbuf('get_option', 'undolevels'))
+    end)
   end)
 
   describe('nvim_buf_get_name, nvim_buf_set_name', function()
diff --git a/test/functional/api/vim_spec.lua b/test/functional/api/vim_spec.lua
index 21de4925b5..d53208a915 100644
--- a/test/functional/api/vim_spec.lua
+++ b/test/functional/api/vim_spec.lua
@@ -949,6 +949,33 @@ describe('API', function()
     end)
   end)
 
+  describe('nvim_get_option_value, nvim_set_option_value', function()
+    it('works', function()
+      ok(nvim('get_option_value', 'equalalways', {}))
+      nvim('set_option_value', 'equalalways', false, {})
+      ok(not nvim('get_option_value', 'equalalways', {}))
+    end)
+
+    it('can get local values when global value is set', function()
+      eq(0, nvim('get_option_value', 'scrolloff', {}))
+      eq(-1, nvim('get_option_value', 'scrolloff', {scope = 'local'}))
+    end)
+
+    it('can set global and local values', function()
+      nvim('set_option_value', 'makeprg', 'hello', {})
+      eq('hello', nvim('get_option_value', 'makeprg', {}))
+      eq('', nvim('get_option_value', 'makeprg', {scope = 'local'}))
+      nvim('set_option_value', 'makeprg', 'world', {scope = 'local'})
+      eq('world', nvim('get_option_value', 'makeprg', {scope = 'local'}))
+      nvim('set_option_value', 'makeprg', 'goodbye', {scope = 'global'})
+      eq('goodbye', nvim('get_option_value', 'makeprg', {scope = 'global'}))
+      nvim('set_option_value', 'makeprg', 'hello', {})
+      eq('hello', nvim('get_option_value', 'makeprg', {scope = 'global'}))
+      eq('hello', nvim('get_option_value', 'makeprg', {}))
+      eq('', nvim('get_option_value', 'makeprg', {scope = 'local'}))
+    end)
+  end)
+
   describe('nvim_{get,set}_current_buf, nvim_list_bufs', function()
     it('works', function()
       eq(1, #nvim('list_bufs'))
diff --git a/test/functional/api/window_spec.lua b/test/functional/api/window_spec.lua
index 11755a9d97..4d2ffa316a 100644
--- a/test/functional/api/window_spec.lua
+++ b/test/functional/api/window_spec.lua
@@ -222,9 +222,9 @@ describe('API/win', function()
       eq('', nvim('get_option', 'statusline'))
       command("set modified")
       command("enew") -- global-local: not preserved in new buffer
-      eq("Failed to get value for option 'statusline'",
-        pcall_err(curwin, 'get_option', 'statusline'))
-      eq('', eval('&l:statusline')) -- confirm local value was not copied
+      -- confirm local value was not copied
+      eq('', curwin('get_option', 'statusline'))
+      eq('', eval('&l:statusline'))
     end)
 
     it('after switching windows #15390', function()
@@ -238,6 +238,10 @@ describe('API/win', function()
       eq('window-status', window('get_option', win1, 'statusline'))
       assert_alive()
     end)
+
+    it('returns values for unset local options', function()
+      eq(-1, curwin('get_option', 'scrolloff'))
+    end)
   end)
 
   describe('get_position', function()
diff --git a/test/functional/lua/vim_spec.lua b/test/functional/lua/vim_spec.lua
index 28471bdd46..2515b37beb 100644
--- a/test/functional/lua/vim_spec.lua
+++ b/test/functional/lua/vim_spec.lua
@@ -1240,7 +1240,7 @@ describe('lua stdlib', function()
 
         vim.opt.makeprg = "global-local"
         table.insert(result, vim.api.nvim_get_option('makeprg'))
-        table.insert(result, (pcall(vim.api.nvim_buf_get_option, 0, 'makeprg')))
+        table.insert(result, vim.api.nvim_buf_get_option(0, 'makeprg'))
 
         vim.opt_local.mp = "only-local"
         table.insert(result, vim.api.nvim_get_option('makeprg'))
@@ -1258,7 +1258,7 @@ describe('lua stdlib', function()
 
       -- Set -> global & local
       eq("global-local", result[1])
-      eq(false, result[2])
+      eq("", result[2])
 
       -- Setlocal -> only local
       eq("global-local", result[3])
@@ -1268,9 +1268,9 @@ describe('lua stdlib', function()
       eq("only-global", result[5])
       eq("only-local", result[6])
 
-      -- set -> doesn't override previously set value
+      -- Set -> sets global value and resets local value
       eq("global-local", result[7])
-      eq("only-local", result[8])
+      eq("", result[8])
     end)
 
     it('should allow you to retrieve window opts even if they have not been set', function()