Data overrides in template hide chained object properties

[OldStarchy]

Affected Version

4.6.2

Description

Given the following PHP and template

$email = Email::create($from, $to, $subject);
$email->setHTMLTemplate('Email\\Foo');
$email->setData([
    'Link' => 'Literal Link',
    'Page' => $somePage,
]);
$email->send();

Email/Foo.ss

Link             => $Link
Page Action Link => $Page.Link('my_action')

The expected output is

Link             => Literal Link
Page Action Link => page-slug/my_action

However, the actual output comes through as

Link             => Literal Link
Page Action Link => Literal Link

Stepping through the code I found the part where its calling XML_val in the template

$val .= $scope->locally()->obj('Page', null, true)->XML_val('Link', ['my_action'], true);

This leads to SSViewer_DataPresenter.php#L350, where processTemplateOverride sees that Link is defined and ignores the fact that it should be scoped to $Page.

[michalkleiner]

$Page is a special global template variable that can get a page by its slug, and defaults to the current page if no slug is provided (afaik), so using it to provide custom data to a template isn't recommended. If you use any other custom variable to pass in your custom page object, such as MyPage, it will work ok, I believe.

[michalkleiner]

Ok, it seems to fallback to the homepage based on this (https://github.com/silverstripe/silverstripe-cms/blob/4/code/Controllers/ContentController.php#L134) and the subsequent calls.

I'd still recommend renaming the variable, it's the safest thing.

[OldStarchy]

I used Page as an example, in my actual code I had

$email->setData([
    'AbsoluteBaseURL' => Director::absoluteBaseURL(),
    'Link' => $productSelection->getSelectionLink(),
    'CustomerFollowupPage' => $customerFollowupPage,
]);

I've changed it to

$email->setData([
    'AbsoluteBaseURL' => Director::absoluteBaseURL(),
    'ProductSelection' => $productSelection,
    'CustomerFollowupPage' => $customerFollowupPage,
]);