fix(api): notify dict watchers on nvim_set_var and vim.g setter

Co-authored-by: bfredl <bjorn.linse@gmail.com>
Co-authored-by: Christian Clason <c.clason@uni-graz.at>

src/nvim/api/private/helpers.c

@@ -218,6 +218,8 @@ Object dict_set_var(dict_T *dict, String key, Object value, bool del, bool retva
     return rv;
   }
 
+  bool watched = tv_dict_is_watched(dict);
+
   if (del) {
     // Delete the key
     if (di == NULL) {
@@ -225,6 +227,10 @@ Object dict_set_var(dict_T *dict, String key, Object value, bool del, bool retva
       api_set_error(err, kErrorTypeValidation, "Key not found: %s",
                     key.data);
     } else {
+      // Notify watchers
+      if (watched) {
+        tv_dict_watcher_notify(dict, key.data, NULL, &di->di_tv);
+      }
       // Return the old value
       if (retval) {
         rv = vim_to_object(&di->di_tv);
@@ -241,11 +247,16 @@ Object dict_set_var(dict_T *dict, String key, Object value, bool del, bool retva
       return rv;
     }
 
+    typval_T oldtv = TV_INITIAL_VALUE;
+
     if (di == NULL) {
       // Need to create an entry
       di = tv_dict_item_alloc_len(key.data, key.size);
       tv_dict_add(dict, di);
     } else {
+      if (watched) {
+        tv_copy(&di->di_tv, &oldtv);
+      }
       // Return the old value
       if (retval) {
         rv = vim_to_object(&di->di_tv);
@@ -255,6 +266,13 @@ Object dict_set_var(dict_T *dict, String key, Object value, bool del, bool retva
 
     // Update the value
     tv_copy(&tv, &di->di_tv);
+
+    // Notify watchers
+    if (watched) {
+      tv_dict_watcher_notify(dict, key.data, &tv, &oldtv);
+      tv_clear(&oldtv);
+    }
+
     // Clear the temporary variable
     tv_clear(&tv);
   }

src/nvim/eval/typval.c

@@ -1781,7 +1781,7 @@ void tv_dict_watcher_notify(dict_T *const dict, const char *const key, typval_T
     tv_dict_add(argv[2].vval.v_dict, v);
   }
 
-  if (oldtv) {
+  if (oldtv && oldtv->v_type != VAR_UNKNOWN) {
     dictitem_T *const v = tv_dict_item_alloc_len(S_LEN("old"));
     tv_copy(oldtv, &v->di_tv);
     tv_dict_add(argv[2].vval.v_dict, v);

src/nvim/eval/vars.c

@@ -1348,12 +1348,8 @@ void set_var_const(const char *name, const size_t name_len, typval_T *const tv,
   }
 
   if (watched) {
-    if (oldtv.v_type == VAR_UNKNOWN) {
-      tv_dict_watcher_notify(dict, (char *)v->di_key, &v->di_tv, NULL);
-    } else {
-      tv_dict_watcher_notify(dict, (char *)v->di_key, &v->di_tv, &oldtv);
-      tv_clear(&oldtv);
-    }
+    tv_dict_watcher_notify(dict, (char *)v->di_key, &v->di_tv, &oldtv);
+    tv_clear(&oldtv);
   }
 
   if (is_const) {

src/nvim/lua/stdlib.c

@@ -369,12 +369,19 @@ int nlua_setvar(lua_State *lstate)
     return 0;
   }
 
+  bool watched = tv_dict_is_watched(dict);
+
   if (del) {
     // Delete the key
     if (di == NULL) {
       // Doesn't exist, nothing to do
       return 0;
     } else {
+      // Notify watchers
+      if (watched) {
+        tv_dict_watcher_notify(dict, key.data, NULL, &di->di_tv);
+      }
+
       // Delete the entry
       tv_dict_item_remove(dict, di);
     }
@@ -388,17 +395,29 @@ int nlua_setvar(lua_State *lstate)
       return luaL_error(lstate, "Couldn't convert lua value");
     }
 
+    typval_T oldtv = TV_INITIAL_VALUE;
+
     if (di == NULL) {
       // Need to create an entry
       di = tv_dict_item_alloc_len(key.data, key.size);
       tv_dict_add(dict, di);
     } else {
+      if (watched) {
+        tv_copy(&di->di_tv, &oldtv);
+      }
       // Clear the old value
       tv_clear(&di->di_tv);
     }
 
     // Update the value
     tv_copy(&tv, &di->di_tv);
+
+    // Notify watchers
+    if (watched) {
+      tv_dict_watcher_notify(dict, key.data, &tv, &oldtv);
+      tv_clear(&oldtv);
+    }
+
     // Clear the temporary variable
     tv_clear(&tv);
   }

test/functional/ex_cmds/dict_notifications_spec.lua

@@ -4,6 +4,7 @@ local clear, nvim, source = helpers.clear, helpers.nvim, helpers.source
 local insert = helpers.insert
 local eq, next_msg = helpers.eq, helpers.next_msg
 local exc_exec = helpers.exc_exec
+local exec_lua = helpers.exec_lua
 local command = helpers.command
 local eval = helpers.eval
 
@@ -21,6 +22,8 @@ describe('VimL dictionary notifications', function()
   -- t:) and a dictionary variable, so we generate them in the following
   -- function.
   local function gentests(dict_expr, dict_init)
+    local is_g = dict_expr == 'g:'
+
     local function update(opval, key)
       if not key then
         key = 'watched'
@@ -32,6 +35,28 @@ describe('VimL dictionary notifications', function()
       end
     end
 
+    local function update_with_api(opval, key)
+      if not key then
+        key = 'watched'
+      end
+      if opval == '' then
+        exec_lua(('vim.api.nvim_del_var(\'%s\')'):format(key))
+      else
+        exec_lua(('vim.api.nvim_set_var(\'%s\', %s)'):format(key, opval))
+      end
+    end
+
+    local function update_with_vim_g(opval, key)
+      if not key then
+        key = 'watched'
+      end
+      if opval == '' then
+        exec_lua(('vim.g.%s = nil'):format(key))
+      else
+        exec_lua(('vim.g.%s %s'):format(key, opval))
+      end
+    end
+
     local function verify_echo()
       -- helper to verify that no notifications are sent after certain change
       -- to a dict
@@ -76,6 +101,18 @@ describe('VimL dictionary notifications', function()
         update('', 'watched2')
         update('')
         verify_echo()
+        if is_g then
+          update_with_api('"test"')
+          update_with_api('"test2"', 'watched2')
+          update_with_api('', 'watched2')
+          update_with_api('')
+          verify_echo()
+          update_with_vim_g('= "test"')
+          update_with_vim_g('= "test2"', 'watched2')
+          update_with_vim_g('', 'watched2')
+          update_with_vim_g('')
+          verify_echo()
+        end
       end)
 
       it('is not triggered when unwatched keys are updated', function()
@@ -83,6 +120,16 @@ describe('VimL dictionary notifications', function()
         update('.= "noop2"', 'unwatched')
         update('', 'unwatched')
         verify_echo()
+        if is_g then
+          update_with_api('"noop"', 'unwatched')
+          update_with_api('vim.g.unwatched .. "noop2"', 'unwatched')
+          update_with_api('', 'unwatched')
+          verify_echo()
+          update_with_vim_g('= "noop"', 'unwatched')
+          update_with_vim_g('= vim.g.unwatched .. "noop2"', 'unwatched')
+          update_with_vim_g('', 'unwatched')
+          verify_echo()
+        end
       end)
 
       it('is triggered by remove()', function()
@@ -92,6 +139,22 @@ describe('VimL dictionary notifications', function()
         verify_value({old = 'test'})
       end)
 
+      if is_g then
+        it('is triggered by remove() when updated with nvim_*_var', function()
+          update_with_api('"test"')
+          verify_value({new = 'test'})
+          nvim('command', 'call remove('..dict_expr..', "watched")')
+          verify_value({old = 'test'})
+        end)
+
+        it('is triggered by remove() when updated with vim.g', function()
+          update_with_vim_g('= "test"')
+          verify_value({new = 'test'})
+          nvim('command', 'call remove('..dict_expr..', "watched")')
+          verify_value({old = 'test'})
+        end)
+      end
+
       it('is triggered by extend()', function()
         update('= "xtend"')
         verify_value({new = 'xtend'})