patch 8.2.4260: Vim9: can still use a global function without g:

Problem:    Vim9: can still use a global function without g: at the script
            level.
Solution:   Also check for g: at the script level. (issue #9637)

src/evalvars.c

@@ -2779,17 +2779,20 @@ eval_variable(
 	}
 	else if (in_vim9script() && (flags & EVAL_VAR_NO_FUNC) == 0)
 	{
+	    int	    has_g_prefix = STRNCMP(name, "g:", 2) == 0;
 	    ufunc_T *ufunc = find_func(name, FALSE);
 
 	    // In Vim9 script we can get a function reference by using the
-	    // function name.
-	    if (ufunc != NULL)
+	    // function name.  For a global non-autoload function "g:" is
+	    // required.
+	    if (ufunc != NULL && (has_g_prefix
+					    || !func_requires_g_prefix(ufunc)))
 	    {
 		found = TRUE;
 		if (rettv != NULL)
 		{
 		    rettv->v_type = VAR_FUNC;
-		    if (STRNCMP(name, "g:", 2) == 0)
+		    if (has_g_prefix)
 			// Keep the "g:", otherwise script-local may be
 			// assumed.
 			rettv->vval.v_string = vim_strsave(name);

src/proto/userfunc.pro

@@ -11,6 +11,7 @@ char_u *fname_trans_sid(char_u *name, char_u *fname_buf, char_u **tofree, int *e
 ufunc_T *find_func_even_dead(char_u *name, int flags);
 ufunc_T *find_func(char_u *name, int is_global);
 int func_is_global(ufunc_T *ufunc);
+int func_requires_g_prefix(ufunc_T *ufunc);
 int func_name_refcount(char_u *name);
 void func_clear_free(ufunc_T *fp, int force);
 int copy_func(char_u *lambda, char_u *global, ectx_T *ectx);

src/testdir/dumps/Test_popupwin_scroll_11.dump

@@ -7,4 +7,4 @@
 |7| @20|4+0#0000001#ffd7ff255| @28| +0#0000000#a8a8a8255| +0&#ffffff0@21
 |8| @73
 |9| @73
-|:|c|a|l@1| |P|o|p|u|p|S|c|r|o|l@1|(|)| @37|1|,|1| @10|T|o|p| 
+|:|c|a|l@1| |g|:|P|o|p|u|p|S|c|r|o|l@1|(|)| @35|1|,|1| @10|T|o|p| 

src/testdir/dumps/Test_popupwin_scroll_12.dump

@@ -7,4 +7,4 @@
 |7| @20|l+0#0000001#ffd7ff255|o|n|g| |l|i|n|e| |l|o|n|g| |l|i|n|e| |l|o|n|g| |l|i|n|e| | +0#0000000#a8a8a8255| +0&#ffffff0@21
 |8| @73
 |9| @73
-|:|c|a|l@1| |P|o|p|u|p|S|c|r|o|l@1|(|)| @37|1|,|1| @10|T|o|p| 
+|:|c|a|l@1| |g|:|P|o|p|u|p|S|c|r|o|l@1|(|)| @35|1|,|1| @10|T|o|p| 

src/testdir/test_ins_complete.vim

@@ -1422,7 +1422,7 @@ func Test_completefunc_callback()
     call assert_fails("set completefunc=funcref('abc')", "E700:")
 
     #" set 'completefunc' to a non-existing function
-    set completefunc=CompleteFunc2
+    set completefunc=g:CompleteFunc2
     call setline(1, 'five')
     call assert_fails("set completefunc=function('NonExistingFunc')", 'E700:')
     call assert_fails("LET &completefunc = function('NonExistingFunc')", 'E700:')
@@ -1679,7 +1679,7 @@ func Test_omnifunc_callback()
     call assert_fails("set omnifunc=funcref('abc')", "E700:")
 
     #" set 'omnifunc' to a non-existing function
-    set omnifunc=OmniFunc2
+    set omnifunc=g:OmniFunc2
     call setline(1, 'nine')
     call assert_fails("set omnifunc=function('NonExistingFunc')", 'E700:')
     call assert_fails("LET &omnifunc = function('NonExistingFunc')", 'E700:')
@@ -1936,7 +1936,7 @@ func Test_thesaurusfunc_callback()
     call assert_fails("set thesaurusfunc=funcref('abc')", "E700:")
 
     #" set 'thesaurusfunc' to a non-existing function
-    set thesaurusfunc=TsrFunc2
+    set thesaurusfunc=g:TsrFunc2
     call setline(1, 'ten')
     call assert_fails("set thesaurusfunc=function('NonExistingFunc')", 'E700:')
     call assert_fails("LET &thesaurusfunc = function('NonExistingFunc')", 'E700:')

src/testdir/test_popupwin.vim

@@ -2263,7 +2263,7 @@ func Test_popup_scrollbar()
 	    \ wrap: true,
 	    \ scrollbar: true,
 	    \ mapping: false,
-	    \ filter: Popup_filter,
+	    \ filter: g:Popup_filter,
 	    \ })
     enddef
 
@@ -2328,7 +2328,7 @@ func Test_popup_scrollbar()
   call VerifyScreenDump(buf, 'Test_popupwin_scroll_10', {})
 
   " check size with non-wrapping lines
-  call term_sendkeys(buf, ":call PopupScroll()\<CR>")
+  call term_sendkeys(buf, ":call g:PopupScroll()\<CR>")
   call VerifyScreenDump(buf, 'Test_popupwin_scroll_11', {})
 
   " check size with wrapping lines

src/testdir/test_vim9_assign.vim

@@ -75,7 +75,7 @@ def Test_assignment()
 
   # lower case name is OK for a list
   var lambdaLines =<< trim END
-      var lambdaList: list<func> = [Test_syntax]
+      var lambdaList: list<func> = [g:Test_syntax]
       lambdaList[0] = () => "lambda"
   END
   v9.CheckDefAndScriptSuccess(lambdaLines)
@@ -890,7 +890,7 @@ enddef
 
 def Test_assignment_partial()
   var lines =<< trim END
-      var Partial: func(): string = function(PartFuncBool, [true])
+      var Partial: func(): string = function(g:PartFuncBool, [true])
       assert_equal('done', Partial())
   END
   v9.CheckDefAndScriptSuccess(lines)
@@ -1393,7 +1393,7 @@ def Test_assignment_failure()
   v9.CheckDefFailure(['var name: dict <number>'], 'E1068:')
   v9.CheckDefFailure(['var name: dict<number'], 'E1009:')
 
-  assert_fails('s/^/\=Mess()/n', 'E794:')
+  assert_fails('s/^/\=g:Mess()/n', 'E794:')
   v9.CheckDefFailure(['var name: dict<number'], 'E1009:')
 
   v9.CheckDefFailure(['w:foo: number = 10'],

src/testdir/test_vim9_builtin.vim

@@ -1303,7 +1303,7 @@ def Test_filter()
 enddef
 
 def Test_filter_wrong_dict_key_type()
-  assert_fails('Wrong_dict_key_type([1, v:null, 3])', 'E1013:')
+  assert_fails('g:Wrong_dict_key_type([1, v:null, 3])', 'E1013:')
 enddef
 
 def Test_filter_return_type()

src/testdir/test_vim9_cmd.vim

@@ -1324,7 +1324,7 @@ def Test_gdefault_not_used()
   bwipe!
 enddef
 
-def g:SomeComplFunc(findstart: number, base: string): any
+def s:SomeComplFunc(findstart: number, base: string): any
   if findstart
     return 0
   else

src/testdir/test_vim9_disassemble.vim

@@ -887,7 +887,7 @@ def Test_disassemble_call_default()
 enddef
 
 
-def HasEval()
+def s:HasEval()
   if has("eval")
     echo "yes"
   else
@@ -895,7 +895,7 @@ def HasEval()
   endif
 enddef
 
-def HasNothing()
+def s:HasNothing()
   if has("nothing")
     echo "yes"
   else
@@ -903,7 +903,7 @@ def HasNothing()
   endif
 enddef
 
-def HasSomething()
+def s:HasSomething()
   if has("nothing")
     echo "nothing"
   elseif has("something")
@@ -915,7 +915,7 @@ def HasSomething()
   endif
 enddef
 
-def HasGuiRunning()
+def s:HasGuiRunning()
   if has("gui_running")
     echo "yes"
   else
@@ -2487,7 +2487,7 @@ def Test_debug_for()
         res)
 enddef
 
-func Legacy() dict
+func s:Legacy() dict
   echo 'legacy'
 endfunc
 
@@ -2501,7 +2501,7 @@ def Test_disassemble_dict_stack()
   assert_match('<SNR>\d*_UseMember\_s*' ..
           'var d = {func: Legacy}\_s*' ..
           '\d PUSHS "func"\_s*' ..
-          '\d PUSHFUNC "g:Legacy"\_s*' ..
+          '\d PUSHFUNC "<80><fd>R\d\+_Legacy"\_s*' ..
           '\d NEWDICT size 1\_s*' ..
           '\d STORE $0\_s*' ..
 

src/testdir/test_vim9_expr.vim

@@ -61,12 +61,17 @@ def Test_expr1_trinary()
       var RetThat: func = g:atrue ? RetOne : RetTwo
       assert_equal(function('len'), RetThat)
 
-      var X = FuncOne
-      var Y = FuncTwo
-      var Z = g:cond ? FuncOne : FuncTwo
+      var X = g:FuncOne
+      var Y = g:FuncTwo
+      var Z = g:cond ? g:FuncOne : g:FuncTwo
       assert_equal(123, Z(3))
   END
   v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+      var Z = g:cond ? FuncOne : FuncTwo
+  END
+  v9.CheckDefAndScriptFailure(lines, ['E1001: Variable not found: FuncOne', 'E121: Undefined variable: FuncTwo'])
 enddef
 
 def Test_expr1_trinary_vimscript()
@@ -209,9 +214,9 @@ func Test_expr1_trinary_fails()
 
   " missing argument detected even when common type is used
   call v9.CheckDefAndScriptFailure([
-	\ 'var X = FuncOne',
-	\ 'var Y = FuncTwo',
-	\ 'var Z = g:cond ? FuncOne : FuncTwo',
+	\ 'var X = g:FuncOne',
+	\ 'var Y = g:FuncTwo',
+	\ 'var Z = g:cond ? g:FuncOne : g:FuncTwo',
 	\ 'Z()'], 'E119:', 4)
 endfunc
 
@@ -2334,7 +2339,7 @@ def Test_expr8_funcref()
       def Test()
         var Ref = g:GlobalFunc
         assert_equal('global', Ref())
-        Ref = GlobalFunc
+        Ref = g:GlobalFunc
         assert_equal('global', Ref())
 
         Ref = s:ScriptFunc
@@ -3083,12 +3088,12 @@ def Test_expr8_call()
   v9.CheckDefAndScriptFailure(["var Ref = function('len' [1, 2])"], ['E1123:', 'E116:'], 1)
 enddef
 
-def g:ExistingGloba(): string
+def g:ExistingGlobal(): string
   return 'existing'
 enddef
 
 def Test_expr8_call_global()
-  assert_equal('existing', g:ExistingGloba())
+  assert_equal('existing', g:ExistingGlobal())
 
   def g:DefinedLater(): string
     return 'later'

src/testdir/test_vim9_func.vim

@@ -340,7 +340,7 @@ enddef
 def Test_return_something()
   g:ReturnString()->assert_equal('string')
   g:ReturnNumber()->assert_equal(123)
-  assert_fails('ReturnGlobal()', 'E1012: Type mismatch; expected number but got string', '', 1, 'ReturnGlobal')
+  assert_fails('g:ReturnGlobal()', 'E1012: Type mismatch; expected number but got string', '', 1, 'ReturnGlobal')
 
   var lines =<< trim END
       vim9script
@@ -943,7 +943,7 @@ def Test_local_function_shadows_global()
       def g:Func(): string
         return 'global'
       enddef
-      assert_equal('global', Func())
+      assert_equal('global', g:Func())
       delfunc g:Func
   END
   v9.CheckScriptSuccess(lines)
@@ -1498,14 +1498,14 @@ enddef
 
 def Test_func_type_varargs()
   var RefDefArg: func(?string)
-  RefDefArg = FuncOneDefArg
+  RefDefArg = g:FuncOneDefArg
   RefDefArg()
   s:value->assert_equal('text')
   RefDefArg('some')
   s:value->assert_equal('some')
 
   var RefDef2Arg: func(?number, ?string): string
-  RefDef2Arg = FuncTwoDefArg
+  RefDef2Arg = g:FuncTwoDefArg
   RefDef2Arg()->assert_equal('123text')
   RefDef2Arg(99)->assert_equal('99text')
   RefDef2Arg(77, 'some')->assert_equal('77some')
@@ -1514,7 +1514,7 @@ def Test_func_type_varargs()
   v9.CheckDefFailure(['var RefWrong: func(?string, string)'], 'E1007:')
 
   var RefVarargs: func(...list<string>): string
-  RefVarargs = FuncVarargs
+  RefVarargs = g:FuncVarargs
   RefVarargs()->assert_equal('')
   RefVarargs('one')->assert_equal('one')
   RefVarargs('one', 'two')->assert_equal('one,two')
@@ -1721,7 +1721,7 @@ enddef
 
 def Test_error_in_nested_function()
   # Error in called function requires unwinding the call stack.
-  assert_fails('FuncWithForwardCall()', 'E1096:', '', 1, 'FuncWithForwardCall')
+  assert_fails('g:FuncWithForwardCall()', 'E1096:', '', 1, 'FuncWithForwardCall')
 enddef
 
 def Test_nested_function_with_nextcmd()
@@ -2199,7 +2199,7 @@ def Test_func_type()
   s:funcResult->assert_equal(22)
 
   s:funcResult = 0
-  Ref2 = FuncOneArgRetNumber
+  Ref2 = g:FuncOneArgRetNumber
   Ref2(13)->assert_equal(13)
   s:funcResult->assert_equal(13)
 enddef
@@ -2232,11 +2232,11 @@ def Test_func_type_part()
   RefVoid = g:FuncNoArgNoRet
   RefVoid = g:FuncOneArgNoRet
   v9.CheckDefFailure(['var RefVoid: func: void', 'RefVoid = g:FuncNoArgRetNumber'], 'E1012: Type mismatch; expected func(...) but got func(): number')
-  v9.CheckDefFailure(['var RefVoid: func: void', 'RefVoid = FuncNoArgRetString'], 'E1012: Type mismatch; expected func(...) but got func(): string')
+  v9.CheckDefFailure(['var RefVoid: func: void', 'RefVoid = g:FuncNoArgRetString'], 'E1012: Type mismatch; expected func(...) but got func(): string')
 
   var RefAny: func(): any
   RefAny = g:FuncNoArgRetNumber
-  RefAny = FuncNoArgRetString
+  RefAny = g:FuncNoArgRetString
   v9.CheckDefFailure(['var RefAny: func(): any', 'RefAny = g:FuncNoArgNoRet'], 'E1012: Type mismatch; expected func(): any but got func()')
   v9.CheckDefFailure(['var RefAny: func(): any', 'RefAny = g:FuncOneArgNoRet'], 'E1012: Type mismatch; expected func(): any but got func(number)')
 
@@ -2244,12 +2244,12 @@ def Test_func_type_part()
 
   var RefNr: func: number
   RefNr = g:FuncNoArgRetNumber
-  RefNr = FuncOneArgRetNumber
+  RefNr = g:FuncOneArgRetNumber
   v9.CheckDefFailure(['var RefNr: func: number', 'RefNr = g:FuncNoArgNoRet'], 'E1012: Type mismatch; expected func(...): number but got func()')
-  v9.CheckDefFailure(['var RefNr: func: number', 'RefNr = FuncNoArgRetString'], 'E1012: Type mismatch; expected func(...): number but got func(): string')
+  v9.CheckDefFailure(['var RefNr: func: number', 'RefNr = g:FuncNoArgRetString'], 'E1012: Type mismatch; expected func(...): number but got func(): string')
 
   var RefStr: func: string
-  RefStr = FuncNoArgRetString
+  RefStr = g:FuncNoArgRetString
   RefStr = FuncOneArgRetString
   v9.CheckDefFailure(['var RefStr: func: string', 'RefStr = g:FuncNoArgNoRet'], 'E1012: Type mismatch; expected func(...): string but got func()')
   v9.CheckDefFailure(['var RefStr: func: string', 'RefStr = g:FuncNoArgRetNumber'], 'E1012: Type mismatch; expected func(...): string but got func(): number')
@@ -2260,7 +2260,7 @@ def Test_func_type_fails()
 
   v9.CheckDefFailure(['var Ref1: func()', 'Ref1 = g:FuncNoArgRetNumber'], 'E1012: Type mismatch; expected func() but got func(): number')
   v9.CheckDefFailure(['var Ref1: func()', 'Ref1 = g:FuncOneArgNoRet'], 'E1012: Type mismatch; expected func() but got func(number)')
-  v9.CheckDefFailure(['var Ref1: func()', 'Ref1 = FuncOneArgRetNumber'], 'E1012: Type mismatch; expected func() but got func(number): number')
+  v9.CheckDefFailure(['var Ref1: func()', 'Ref1 = g:FuncOneArgRetNumber'], 'E1012: Type mismatch; expected func() but got func(number): number')
   v9.CheckDefFailure(['var Ref1: func(bool)', 'Ref1 = g:FuncTwoArgNoRet'], 'E1012: Type mismatch; expected func(bool) but got func(bool, number)')
   v9.CheckDefFailure(['var Ref1: func(?bool)', 'Ref1 = g:FuncTwoArgNoRet'], 'E1012: Type mismatch; expected func(?bool) but got func(bool, number)')
   v9.CheckDefFailure(['var Ref1: func(...bool)', 'Ref1 = g:FuncTwoArgNoRet'], 'E1012: Type mismatch; expected func(...bool) but got func(bool, number)')
@@ -3355,7 +3355,7 @@ def Test_skip_cmds_with_silent()
 enddef
 
 def Test_opfunc()
-  nnoremap <F3> <cmd>set opfunc=Opfunc<cr>g@
+  nnoremap <F3> <cmd>set opfunc=g:Opfunc<cr>g@
   def g:Opfunc(_: any): string
     setline(1, 'ASDF')
     return ''

src/testdir/test_vim9_import.vim

@@ -2018,7 +2018,7 @@ def Test_autoload_missing_function_name()
   delete('Xdir', 'rf')
 enddef
 
-def Test_autoload_name_wring()
+def Test_autoload_name_wrong()
   var lines =<< trim END
      vim9script
      def Xscriptname#Func()

src/userfunc.c

@@ -1902,7 +1902,7 @@ find_func_with_prefix(char_u *name, int sid)
     char_u	    buffer[200];
     scriptitem_T    *si;
 
-    if (vim_strchr(name, AUTOLOAD_CHAR) != 0)
+    if (vim_strchr(name, AUTOLOAD_CHAR) != NULL)
 	return NULL;	// already has the prefix
     if (!SCRIPT_ID_VALID(sid))
 	return NULL;	// not in a script
@@ -2004,6 +2004,17 @@ func_is_global(ufunc_T *ufunc)
     return ufunc->uf_name[0] != K_SPECIAL;
 }
 
+/*
+ * Return TRUE if "ufunc" must be called with a g: prefix in Vim9 script.
+ */
+    int
+func_requires_g_prefix(ufunc_T *ufunc)
+{
+    return ufunc->uf_name[0] != K_SPECIAL
+	    && (ufunc->uf_flags & FC_LAMBDA) == 0
+	    && vim_strchr(ufunc->uf_name, AUTOLOAD_CHAR) == NULL;
+}
+
 /*
  * Copy the function name of "fp" to buffer "buf".
  * "buf" must be able to hold the function name plus three bytes.
@@ -3442,7 +3453,14 @@ call_func(
 	     * User defined function.
 	     */
 	    if (fp == NULL)
+	    {
 		fp = find_func(rfname, is_global);
+		if (fp != NULL && !is_global && in_vim9script()
+						 && func_requires_g_prefix(fp))
+		    // In Vim9 script g: is required to find a global
+		    // non-autoload function.
+		    fp = NULL;
+	    }
 
 	    // Trigger FuncUndefined event, may load the function.
 	    if (fp == NULL
@@ -3672,6 +3690,7 @@ trans_function_name(
     char_u	sid_buf[20];
     int		len;
     int		extra = 0;
+    int		prefix_g = FALSE;
     lval_T	lv;
     int		vim9script;
 
@@ -3837,8 +3856,20 @@ trans_function_name(
 	// skip over "s:" and "g:"
 	if (lead == 2 || (lv.ll_name[0] == 'g' && lv.ll_name[1] == ':'))
 	{
-	    if (is_global != NULL && lv.ll_name[0] == 'g')
-		*is_global = TRUE;
+	    if (lv.ll_name[0] == 'g')
+	    {
+		if (is_global != NULL)
+		{
+		    *is_global = TRUE;
+		}
+		else
+		{
+		    // dropping "g:" without setting "is_global" won't work in
+		    // Vim9script, put it back later
+		    prefix_g = TRUE;
+		    extra = 2;
+		}
+	    }
 	    lv.ll_name += 2;
 	}
 	len = (int)(end - lv.ll_name);
@@ -3919,6 +3950,11 @@ trans_function_name(
 	    if (vim9script || lead > 3)	// If it's "<SID>"
 		STRCPY(name + 3, sid_buf);
 	}
+	else if (prefix_g)
+	{
+	    name[0] = 'g';
+	    name[1] = ':';
+	}
 	mch_memmove(name + lead + extra, lv.ll_name, (size_t)len);
 	name[lead + extra + len] = NUL;
     }

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4260,
 /**/
     4259,
 /**/

src/vim9expr.c

@@ -349,11 +349,12 @@ compile_load_scriptvar(
 }
 
     static int
-generate_funcref(cctx_T *cctx, char_u *name)
+generate_funcref(cctx_T *cctx, char_u *name, int has_g_prefix)
 {
     ufunc_T *ufunc = find_func(name, FALSE);
 
-    if (ufunc == NULL)
+    // Reject a global non-autoload function found without the "g:" prefix.
+    if (ufunc == NULL || (!has_g_prefix && func_requires_g_prefix(ufunc)))
 	return FAIL;
 
     // Need to compile any default values to get the argument types.
@@ -420,7 +421,7 @@ compile_load(
 			  break;
 		case 's': if (is_expr && ASCII_ISUPPER(*name)
 				       && find_func(name, FALSE) != NULL)
-			      res = generate_funcref(cctx, name);
+			      res = generate_funcref(cctx, name, FALSE);
 			  else
 			      res = compile_load_scriptvar(cctx, name,
 							    NULL, &end, error);
@@ -429,7 +430,7 @@ compile_load(
 			  {
 			      if (is_expr && ASCII_ISUPPER(*name)
 				       && find_func(name, FALSE) != NULL)
-				  res = generate_funcref(cctx, name);
+				  res = generate_funcref(cctx, name, TRUE);
 			      else
 				  isn_type = ISN_LOADG;
 			  }
@@ -505,7 +506,7 @@ compile_load(
 		// uppercase letter it can be a user defined function.
 		// generate_funcref() will fail if the function can't be found.
 		if (res == FAIL && is_expr && ASCII_ISUPPER(*name))
-		    res = generate_funcref(cctx, name);
+		    res = generate_funcref(cctx, name, FALSE);
 	    }
 	}
 	if (gen_load)
@@ -812,7 +813,7 @@ compile_call(
 
     // If the name is a variable, load it and use PCALL.
     // Not for g:Func(), we don't know if it is a variable or not.
-    // Not for eome#Func(), it will be loaded later.
+    // Not for some#Func(), it will be loaded later.
     p = namebuf;
     if (!has_g_namespace && !is_autoload
 	    && compile_load(&p, namebuf + varlen, cctx, FALSE, FALSE) == OK)