patch 9.2.1252: Vim9: autoload script sourced for an exported value fails

Problem:  When the value of an exported variable sources an autoload
          script, the script fails to load with E1043.
Solution: Reset is_export while sourcing a script, and remove the reset
          added in patch 9.1.1040 (Hirohito Higashi)

closes: #21610

Assisted-by: Claude
Signed-off-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/scriptfile.c

@@ -1663,6 +1663,7 @@ do_source_ext(
     int			    sid = -1;
     scriptitem_T	    *si = NULL;
     int			    save_estack_compiling = estack_compiling;
+    int			    save_is_export = is_export;
     ESTACK_CHECK_DECLARATION;
 #endif
 
@@ -1690,6 +1691,10 @@ do_source_ext(
     }
 #ifdef FEAT_EVAL
     estack_compiling = FALSE;
+    // An ":export" command may source the script, e.g. for an autoload
+    // import used in its value.  That does not export what the script
+    // defines.
+    is_export = FALSE;
 
     // See if we loaded this script before.
     sid = find_script_by_name(fname_exp);
@@ -2089,6 +2094,7 @@ theend:
     sticky_cmdmod_flags = save_sticky_cmdmod_flags;
 #ifdef FEAT_EVAL
     estack_compiling = save_estack_compiling;
+    is_export = save_is_export;
 #endif
     return retval;
 }

src/testdir/test_vim9_import.vim

@@ -3454,6 +3454,34 @@ def Test_imported_class_as_def_func_rettype()
   v9.CheckScriptSuccess(lines)
 enddef
 
+" Test for an autoload script sourced for the value of an exported variable
+def Test_export_value_sources_autoload_script()
+  for kind in ['var', 'const', 'final']
+    var lines =<< trim END
+      vim9script
+      export const VALUE = 42
+      export def Get(): number
+        return 7
+      enddef
+    END
+    writefile(lines, $'Xexportvalue_{kind}1.vim', 'D')
+
+    lines =<< eval trim END
+      vim9script
+      import autoload './Xexportvalue_{kind}1.vim' as A
+      export {kind} x = A.VALUE + A.Get()
+    END
+    writefile(lines, $'Xexportvalue_{kind}2.vim', 'D')
+
+    lines =<< eval trim END
+      vim9script
+      import './Xexportvalue_{kind}2.vim' as B
+      assert_equal(49, B.x)
+    END
+    v9.CheckScriptSuccess(lines)
+  endfor
+enddef
+
 " Test for don't crash when using a combination of import and class extends
 def Test_vim9_import_and_class_extends()
   var lines =<< trim END

src/userfunc.c

@@ -5680,19 +5680,11 @@ define_function(
 	// The function may use script variables from the context.
 	function_using_block_scopes(fp, cstack);
 
-	// The argument types and the return type may use an imported type.
-	// In that case, the imported file will be sourced.  To avoid treating
-	// everything in the imported file as exported, temporarily reset
-	// is_export.
-	int save_is_export = is_export;
-	is_export = FALSE;
-
 	if (parse_argument_types(fp, &argtypes, varargs, &arg_objm,
 				obj_members, obj_member_count, cctx) == FAIL)
 	{
 	    SOURCING_LNUM = lnum_save;
 	    free_fp = fp_allocated;
-	    is_export = save_is_export;
 	    goto erret;
 	}
 	varargs = FALSE;
@@ -5702,10 +5694,8 @@ define_function(
 	{
 	    SOURCING_LNUM = lnum_save;
 	    free_fp = fp_allocated;
-	    is_export = save_is_export;
 	    goto erret;
 	}
-	is_export = save_is_export;
 	SOURCING_LNUM = lnum_save;
     }
     else

src/version.c

@@ -743,6 +743,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1252,
 /**/
     1251,
 /**/