vim-patch:9.2.0265: unnecessary restrictions for defining dictionary function names (#38524)

Problem:  unnecessary restrictions for defining dictionary function
          names
Solution: Allow defining dict function with bracket key that is not a
          valid identifier (thinca)

In Vim script, "function obj.func()" and "function obj['func']()" both
define a dictionary function.  However, the bracket form required the
key to match function naming rules (eval_isnamec), so
"function obj['foo-bar']()" failed with E475.

Assigning and calling already work: "let obj['foo-bar'] = obj.func"
and "call obj['foo-bar']()" are valid.  Only the definition was
incorrectly restricted.

Skip the identifier check when the name comes from fd_newkey (i.e. the
key was given in bracket notation).  Dictionary keys may be any string.

Supported by AI

closes: vim/vim#19833

f89662722d

Co-authored-by: thinca <thinca@gmail.com>

src/nvim/eval/userfunc.c

@@ -2737,21 +2737,27 @@ void ex_function(exarg_T *eap)
     }
     if (arg != NULL && (fudi.fd_di == NULL || !tv_is_func(fudi.fd_di->di_tv))) {
       char *name_base = arg;
-      if ((uint8_t)(*arg) == K_SPECIAL) {
+      // When defining a dictionary function with bracket notation
-        name_base = vim_strchr(arg, '_');
+      // (e.g. obj['foo-bar']()), the key is a dictionary key and is not
-        if (name_base == NULL) {
+      // required to follow function naming rules.  Skip the identifier
-          name_base = arg + 3;
+      // check in that case.
-        } else {
+      if (arg != fudi.fd_newkey) {
-          name_base++;
+        if ((uint8_t)(*arg) == K_SPECIAL) {
+          name_base = vim_strchr(arg, '_');
+          if (name_base == NULL) {
+            name_base = arg + 3;
+          } else {
+            name_base++;
+          }
+        }
+        int i;
+        for (i = 0; name_base[i] != NUL && (i == 0
+                                            ? eval_isnamec1(name_base[i])
+                                            : eval_isnamec(name_base[i])); i++) {}
+        if (name_base[i] != NUL) {
+          emsg_funcname(e_invarg2, arg);
+          goto ret_free;
         }
-      }
-      int i;
-      for (i = 0; name_base[i] != NUL && (i == 0
-                                          ? eval_isnamec1(name_base[i])
-                                          : eval_isnamec(name_base[i])); i++) {}
-      if (name_base[i] != NUL) {
-        emsg_funcname(e_invarg2, arg);
-        goto ret_free;
       }
     }
     // Disallow using the g: dict.

test/old/testdir/test_user_func.vim

@@ -540,6 +540,18 @@ func Test_func_dict()
   call assert_fails('call mydict.nonexist()', 'E716:')
 endfunc
 
+func Test_func_dict_bracket_key()
+  " Dictionary function can be defined with bracket notation using a key
+  " that does not follow function naming rules (e.g. containing a hyphen).
+  let obj = {}
+  function obj['foo-bar']() dict
+    return self.value
+  endfunction
+  let obj.value = 42
+  call assert_equal(42, obj['foo-bar']())
+  call assert_equal(42, call(obj['foo-bar'], []))
+endfunc
+
 func Test_func_range()
   new
   call setline(1, range(1, 8))