Weird scope in 3rd level class when used output buffering - php

Question

I have a master class and semi-master class. Master class core is a class that prints all head, nav, footer and meta elements. Class Base prints content related data and all page-level classes extend it and print their data within specific div.
My problem is that functions and globals are not within scope in one of functions within Base class. Where did I go wrong?
abstract class Core {
abstract protected function print_content();
}
abstract class Base extends Core {
abstract protected function print_page_content();
public function print_content(){
ob_start();
$this->get_nav();
$output = ob_get_contents();
$output .= ' ... '.$this->print_page_content().' ...';
ob_end_clean();
}
}
class Page extends Base {
private function get_games(){...}
private function process_form(){...}
public function print_page_content(){
$this->process_form(); # <--- function doesn't see it (!)
$output = '..... '.$this->get_games().' .... '; # <-- function DOES see this tho (!)
$GLOBALS['m_id']; # <-- or any other global such as $_GET, $_POST is not under scope.
return $output;
}
When I do error reporting it doesn't print any error. It just ignores line where function was called.
However, When I would force error, error would appear.

Answer 1

Let's focus on the technical aspect (and not smaller glitches or design decisions).
I don't think the code snippet you've posted "contains" the error. Let me give you a version that contains everything you've shown us and only adds things that do not "collide" with your code snippet, i.e. minimal implementations of what you've left out (again: purely technical).
<?php
abstract class Core {
abstract protected function print_content();
}
abstract class Base extends Core {
abstract protected function print_page_content();
public function print_content(){
ob_start();
$this->get_nav();
$output = ob_get_contents();
$output .= '###'.$this->print_page_content().'###';
ob_end_clean();
echo $output;
}
public function get_nav() {
echo '| Base::get_nav |';
}
}
class Page extends Base {
protected $names = array();
private function get_games(){ return htmlspecialchars(var_export($this->names, true)); }
private function process_form(){ $this->names['Jean']="D'Arc"; $this->names['John']='Malkovich';}
public function print_page_content(){
$this->process_form();
$output = '<pre>'.$this->get_games().'</pre>';
$output .= '<p>'.$GLOBALS['m_id'].'</p>';
return $output;
}
}
$m_id = 4711;
$p = new Page;
$p->print_content();
it prints
| Base::get_nav |###<pre>array (
'Jean' => 'D\'Arc',
'John' => 'Malkovich',
)</pre><p>4711</p>###
( check here: https://3v4l.org/ZBQ0b )
as it is supposed to do.
So, where does your script differ from this script? Try to minimize your script for testing purposes in order to find the cause.
edit: suggested improvement(s) for your sscce
private function process_form(){
// $stmt = add your prepare()/statement here as a comment
$params = array(/* put in all the variables here, you would bind*/);
// <-- maybe the actual bind code here as comment -->
return var_export( $params, true );
}#endfunc(process_form)
public function print_page_content(){
$pf = $this->process_form();
$output = 'print_page_content stuff...'.$this->get_games()
.' <pre>'.$pf.'</pre>';
return $output;
}#endfunc(print_page_content)

Answer 2

After the abstract class is inherited, the abstract method cannot be rewritten.