Wt

When a session is unsuspended with a Wt::WTextEdit inside a Wt::WTemplate the following js error is thrown:

Wt4_8_2.$(...).ed is undefined

Note that this js function is invoked by WTextEdit::renderRemoveJs which is called by WTemplate::updateDom due to WTextEdit::domCanBeSaved returning true.

Minimal example

root()->addNew<Wt::WTemplate>("${field}")->bindNew<Wt::WTextEdit>("field");
// root()->addNew<Wt::WTextEdit>(); // example works if no `Wt::WTemplate` is used.
root()->addNew<Wt::WPushButton>("Suspend & Resume")->clicked().connect([](){
  wApp->suspend(std::chrono::minutes(15));
  wApp->root()->addNew<Wt::WText>("<p>Suspending ...</p>");
  wApp->redirect(wApp->url("/"));
});
wApp->unsuspended().connect([](){
  wApp->root()->addNew<Wt::WText>("<p>Welcome back after suspending</p>");
});

When clicking on the "Suspend & Resume" button, "Suspending ..." is correctly shown, but the unsuspended signal will never be called due to the js error mentioned above. When the Wt::WTemplate or the Wt::WTextEdit is removed, the session is correctly unsuspended, and "Welcome back after suspending" is shown.

Work-around / solution

Altering WTextEdit::domCanBeSaved to return false solves the issue, but will probably (?) introduce some other regression. Note that WTextEdit::domCanBeSaved was introduced in commit aa198760, but without a clear explanation.

Note that the console output still mentions the following error (but the application seems to be fully functional): "Wt: decodeSignal(): signal 'o18xyg7n.render' not exposed" (with o18xyg7n being the textarea).

A better solution probably is to fix the isRendered check inside WTextEdit::renderRemoveJs.

Note that WFileDropWidget::renderRemoveJs generates a similar bug (i.e. Wt4_8_2.$(...).destructor is undefined) if a WFileDropWidget and a TextEdit are added to the same WWidget (f.ex. WContainerWidget) that is binded to a WTemplate as WFileDropWidget::renderRemoveJs is being called too in that case due to WTextEdit::domCanBeSaved returning true.