hierarchy repeater: fix client-side command in markup control

problem was that that BindingHelper.FindDataContextTarget
assumed there was one more data context layer since we used set
data context type and DataContext on different controls.
Because of that command client-side and server-side
data context paths didn't match.
Technically, this is a glitch of BindingHelper, not HierarchyRepeater,
but "fixing" BindingHelper will break many things and it's hopefully
going to be done in #1392

src/Framework/Framework/Controls/HierarchyRepeater.cs

@@ -258,6 +258,7 @@ private void SetChildren(IDotvvmRequestContext context, bool renderClientTemplat
                 Internal.PathFragmentProperty,
                 $"{GetPathFragmentExpression()}{parentSegment}/[{index}]");
             placeholder.SetValue(Internal.UniqueIDProperty, "item");
+            placeholder.SetDataContextTypeFromDataSource(GetDataSourceBinding()); // DataContext type has to be duplicated on the placeholder, because BindingHelper.FindDataContextTarget (in v4.1)
             dataItem.Children.Add(placeholder);
             ItemTemplate.BuildContent(context, placeholder);
 

src/Tests/ControlTests/testoutputs/HierarchyRepeaterTests.CommandInMarkupControl-server.html

@@ -4,19 +4,19 @@
 
     <div><!-- ko dotvvm-SSR-foreach: { data: HItems } --><!-- ko dotvvm-SSR-item: 0 -->
             <!-- ko with: $rawData --><div>
-            <input type=button value=A onclick='dotvvm.postBack(this,["HItems/[0]","$parents[1]"],"RR93KduwUKJIXxFp","c7_0L_c9",null,[],[],undefined).catch(dotvvm.log.logPostBackScriptError);event.stopPropagation();return false;' /></div><!-- /ko -->
+            <input type=button value=A onclick='dotvvm.postBack(this,["HItems/[0]","$parent"],"RR93KduwUKJIXxFp","c7_0L_c9",null,[],[],undefined).catch(dotvvm.log.logPostBackScriptError);event.stopPropagation();return false;' /></div><!-- /ko -->
         <!-- /ko --><!-- ko dotvvm-SSR-foreach: { data: ko.unwrap($foreachCollectionSymbol)[0]().Children } --><!-- ko dotvvm-SSR-item: 0 -->
             <!-- ko with: $rawData --><div>
-            <input type=button value=A_1 onclick='dotvvm.postBack(this,["HItems/[0]/[0]","$parents[1]"],"RR93KduwUKJIXxFp","c7_0_0L_c9",null,[],[],undefined).catch(dotvvm.log.logPostBackScriptError);event.stopPropagation();return false;' /></div><!-- /ko -->
+            <input type=button value=A_1 onclick='dotvvm.postBack(this,["HItems/[0]/[0]","$parent"],"RR93KduwUKJIXxFp","c7_0_0L_c9",null,[],[],undefined).catch(dotvvm.log.logPostBackScriptError);event.stopPropagation();return false;' /></div><!-- /ko -->
         <!-- /ko --><!-- ko dotvvm-SSR-foreach: { data: ko.unwrap($foreachCollectionSymbol)[0]().Children } --><!-- ko dotvvm-SSR-item: 0 -->
             <!-- ko with: $rawData --><div>
-            <input type=button value=A_1_1 onclick='dotvvm.postBack(this,["HItems/[0]/[0]/[0]","$parents[1]"],"RR93KduwUKJIXxFp","c7_0_0_0L_c9",null,[],[],undefined).catch(dotvvm.log.logPostBackScriptError);event.stopPropagation();return false;' /></div><!-- /ko -->
+            <input type=button value=A_1_1 onclick='dotvvm.postBack(this,["HItems/[0]/[0]/[0]","$parent"],"RR93KduwUKJIXxFp","c7_0_0_0L_c9",null,[],[],undefined).catch(dotvvm.log.logPostBackScriptError);event.stopPropagation();return false;' /></div><!-- /ko -->
         <!-- /ko --><!-- ko dotvvm-SSR-item: 1 -->
             <!-- ko with: $rawData --><div>
-            <input type=button value=A_1_2 onclick='dotvvm.postBack(this,["HItems/[0]/[0]/[1]","$parents[1]"],"RR93KduwUKJIXxFp","c7_0_0_1L_c9",null,[],[],undefined).catch(dotvvm.log.logPostBackScriptError);event.stopPropagation();return false;' /></div><!-- /ko -->
+            <input type=button value=A_1_2 onclick='dotvvm.postBack(this,["HItems/[0]/[0]/[1]","$parent"],"RR93KduwUKJIXxFp","c7_0_0_1L_c9",null,[],[],undefined).catch(dotvvm.log.logPostBackScriptError);event.stopPropagation();return false;' /></div><!-- /ko -->
         <!-- /ko --><!-- /ko --><!-- /ko --><!-- ko dotvvm-SSR-item: 1 -->
             <!-- ko with: $rawData --><div>
-            <input type=button value=B onclick='dotvvm.postBack(this,["HItems/[1]","$parents[1]"],"RR93KduwUKJIXxFp","c7_1L_c9",null,[],[],undefined).catch(dotvvm.log.logPostBackScriptError);event.stopPropagation();return false;' /></div><!-- /ko -->
+            <input type=button value=B onclick='dotvvm.postBack(this,["HItems/[1]","$parent"],"RR93KduwUKJIXxFp","c7_1L_c9",null,[],[],undefined).catch(dotvvm.log.logPostBackScriptError);event.stopPropagation();return false;' /></div><!-- /ko -->
         <!-- /ko --><!-- /ko --></div>