patch 8.2.4137: Vim9: calling import with and without method is inconsistent

Problem:    Vim9: calling import with and without method is inconsistent.
Solution:   Set a flag that a parenthsis follows to compile_load_scriptvar().
            Add some more tests.  Improve error message.

src/testdir/test_vim9_import.vim

@@ -1256,6 +1256,136 @@ def Test_vim9script_autoload()
   &rtp = save_rtp
 enddef
 
+def Test_import_autoload_not_exported()
+  mkdir('Xdir/autoload', 'p')
+  var save_rtp = &rtp
+  exe 'set rtp^=' .. getcwd() .. '/Xdir'
+
+  # error when using an item that is not exported from an autoload script
+  var exportLines =<< trim END
+      vim9script
+      var notExported = 123
+      def NotExport()
+        echo 'nop'
+      enddef
+  END
+  writefile(exportLines, 'Xdir/autoload/notExport1.vim')
+
+  var lines =<< trim END
+      vim9script
+      import autoload 'notExport1.vim'
+      echo notExport1.notFound
+  END
+  CheckScriptFailure(lines, 'E1048: Item not found in script: notFound')
+
+  lines =<< trim END
+      vim9script
+      import autoload 'notExport1.vim'
+      echo notExport1.notExported
+  END
+  CheckScriptFailure(lines, 'E1049: Item not exported in script: notExported')
+
+  lines =<< trim END
+      vim9script
+      import autoload 'notExport1.vim'
+      echo notExport1.NotFunc()
+  END
+  CheckScriptFailure(lines, 'E1048: Item not found in script: NotFunc')
+
+  lines =<< trim END
+      vim9script
+      import autoload 'notExport1.vim'
+      echo notExport1.NotExport()
+  END
+  CheckScriptFailure(lines, 'E1049: Item not exported in script: NotExport')
+
+  lines =<< trim END
+      vim9script
+      import autoload 'notExport1.vim'
+      echo 'text'->notExport1.NotFunc()
+  END
+  CheckScriptFailure(lines, 'E1048: Item not found in script: NotFunc')
+
+  lines =<< trim END
+      vim9script
+      import autoload 'notExport1.vim'
+      echo 'text'->notExport1.NotExport()
+  END
+  CheckScriptFailure(lines, 'E1049: Item not exported in script: NotExport')
+
+  # using a :def function we use a different autoload script every time so that
+  # the function is compiled without the script loaded
+  writefile(exportLines, 'Xdir/autoload/notExport2.vim')
+  lines =<< trim END
+      vim9script
+      import autoload 'notExport2.vim'
+      def Testit()
+        echo notExport2.notFound
+      enddef
+      Testit()
+  END
+  CheckScriptFailure(lines, 'E1048: Item not found in script: notExport2#notFound')
+
+  writefile(exportLines, 'Xdir/autoload/notExport3.vim')
+  lines =<< trim END
+      vim9script
+      import autoload 'notExport3.vim'
+      def Testit()
+        echo notExport3.notExported
+      enddef
+      Testit()
+  END
+  # don't get E1049 because it is too complicated to figure out
+  CheckScriptFailure(lines, 'E1048: Item not found in script: notExport3#notExported')
+
+  writefile(exportLines, 'Xdir/autoload/notExport4.vim')
+  lines =<< trim END
+      vim9script
+      import autoload 'notExport4.vim'
+      def Testit()
+        echo notExport4.NotFunc()
+      enddef
+      Testit()
+  END
+  CheckScriptFailure(lines, 'E117: Unknown function: notExport4#NotFunc')
+
+  writefile(exportLines, 'Xdir/autoload/notExport5.vim')
+  lines =<< trim END
+      vim9script
+      import autoload 'notExport5.vim'
+      def Testit()
+        echo notExport5.NotExport()
+      enddef
+      Testit()
+  END
+  CheckScriptFailure(lines, 'E117: Unknown function: notExport5#NotExport')
+
+  writefile(exportLines, 'Xdir/autoload/notExport6.vim')
+  lines =<< trim END
+      vim9script
+      import autoload 'notExport6.vim'
+      def Testit()
+        echo 'text'->notExport6.NotFunc()
+      enddef
+      Testit()
+  END
+  CheckScriptFailure(lines, 'E117: Unknown function: notExport6#NotFunc')
+
+  writefile(exportLines, 'Xdir/autoload/notExport7.vim')
+  lines =<< trim END
+      vim9script
+      import autoload 'notExport7.vim'
+      def Testit()
+        echo 'text'->notExport7.NotExport()
+      enddef
+      Testit()
+  END
+  CheckScriptFailure(lines, 'E117: Unknown function: notExport7#NotExport')
+
+  delete('Xdir', 'rf')
+  &rtp = save_rtp
+enddef
+
 def Test_vim9script_autoload_call()
   mkdir('Xdir/autoload', 'p')
   var save_rtp = &rtp

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4137,
 /**/
     4136,
 /**/

src/vim9execute.c

@@ -2240,33 +2240,19 @@ exec_instructions(ectx_T *ectx)
 						   iptr->isn_arg.string, TRUE);
 			if (did_emsg)
 			    goto on_error;
-			if (di == NULL)
-			{
-			    isn_T   *next = &ectx->ec_instr[ectx->ec_iidx];
-
-			    // When compiling "script.Func()" when "script" is
-			    // an autoload import then this results in
-			    // "LOADG script#Func" because we don't know if it
-			    // is a funcref variable or a function name.  In
-			    // that case a PCALL follows, push the function
-			    // name instead.
-			    if (next->isn_type == ISN_PCALL)
-			    {
-				tv = STACK_TV_BOT(0);
-				tv->v_type = VAR_FUNC;
-				tv->v_lock = 0;
-				tv->vval.v_string =
-					     vim_strsave(iptr->isn_arg.string);
-				++ectx->ec_stack.ga_len;
-				break;
-			    }
-			}
 		    }
 
 		    if (di == NULL)
 		    {
 			SOURCING_LNUM = iptr->isn_lnum;
-			semsg(_(e_undefined_variable_char_str),
+			if (vim_strchr(iptr->isn_arg.string,
+							AUTOLOAD_CHAR) != NULL)
+			    // no check if the item exists in the script but
+			    // isn't exported, it is too complicated
+			    semsg(_(e_item_not_found_in_script_str),
+							 iptr->isn_arg.string);
+			else
+			    semsg(_(e_undefined_variable_char_str),
 					     namespace, iptr->isn_arg.string);
 			goto on_error;
 		    }

src/vim9expr.c

@@ -21,6 +21,9 @@
 # include "vim9.h"
 #endif
 
+// flag passed from compile_subscript() to compile_load_scriptvar()
+static int paren_follows_after_expr = 0;
+
 /*
  * Generate code for any ppconst entries.
  */
@@ -277,7 +280,6 @@ compile_load_scriptvar(
 	int	done = FALSE;
 	int	res = OK;
 
-	// TODO: if this is an autoload import do something else.
 	// Need to lookup the member.
 	if (*p != '.')
 	{
@@ -306,7 +308,7 @@ compile_load_scriptvar(
 
 	    // autoload script must be loaded later, access by the autoload
 	    // name.
-	    if (cc == '(')
+	    if (cc == '(' || paren_follows_after_expr)
 		res = generate_PUSHFUNC(cctx, auto_name, &t_func_any);
 	    else
 		res = generate_LOAD(cctx, ISN_LOADG, 0, auto_name, &t_any);
@@ -1736,12 +1738,19 @@ compile_subscript(
 		    int save_len = cctx->ctx_ufunc->uf_lines.ga_len;
 
 		    *paren = NUL;
+
+		    // instead of using LOADG for "import.Func" use PUSHFUNC
+		    ++paren_follows_after_expr;
+
 		    // do not look in the next line
 		    cctx->ctx_ufunc->uf_lines.ga_len = 1;
+
 		    fail = compile_expr8(arg, cctx, ppconst) == FAIL
 						    || *skipwhite(*arg) != NUL;
 		    *paren = '(';
+		    --paren_follows_after_expr;
 		    cctx->ctx_ufunc->uf_lines.ga_len = save_len;
+
 		    if (fail)
 		    {
 			semsg(_(e_invalid_expression_str), pstart);

src/vim9script.c

@@ -707,22 +707,36 @@ find_exported(
 	    sprintf((char *)funcname + 3, "%ld_%s", (long)sid, name);
 	}
 	*ufunc = find_func(funcname, FALSE);
-	if (funcname != buffer)
-	    vim_free(funcname);
 
 	if (*ufunc == NULL)
 	{
 	    if (verbose)
-		semsg(_(e_item_not_found_in_script_str), name);
-	    return -1;
+	    {
+		ufunc_T *alt_ufunc = NULL;
+
+		if (script->sn_autoload_prefix != NULL)
+		{
+		    // try find the function by the script-local name
+		    funcname[0] = K_SPECIAL;
+		    funcname[1] = KS_EXTRA;
+		    funcname[2] = (int)KE_SNR;
+		    sprintf((char *)funcname + 3, "%ld_%s", (long)sid, name);
+		    alt_ufunc = find_func(funcname, FALSE);
+		}
+		if (alt_ufunc != NULL)
+		    semsg(_(e_item_not_exported_in_script_str), name);
+		else
+		    semsg(_(e_item_not_found_in_script_str), name);
+	    }
 	}
 	else if (((*ufunc)->uf_flags & FC_EXPORT) == 0)
 	{
 	    if (verbose)
 		semsg(_(e_item_not_exported_in_script_str), name);
 	    *ufunc = NULL;
-	    return -1;
 	}
+	if (funcname != buffer)
+	    vim_free(funcname);
     }
 
     return idx;