Media Library crashed: funtions.php in child theme

Dear Tom,

sorry for bothering you again, but my heart is bleeding after all day fight against this problem.

In details: My media library doesn't work in grid mode (list shows itself nicely) and adds files with lots of troubles. Tried disabling plugins - still same problem, tried changing my child theme into GP parent theme - media library works like brand-new feature.

I know that the problem is caused by my functions.php file in the child theme. Removing it obviously crashes the theme, but media library works then fine. After my research I sadly admit I have no HTML comments in my functions.php file. What's wrong with it then?

Please, help me find a reason. My whole day is wasted. Shame.

<?php
function theme_enqueue_styles() {

    $parent_style = 'generatepress';

    wp_enqueue_style( $parent_style, get_template_directory_uri() . '/style.css' );
    wp_enqueue_style( 'child-style',
        get_stylesheet_directory_uri() . '/style.css',
        array( $parent_style )
    );
}
add_action( 'wp_enqueue_scripts', 'theme_enqueue_styles' );

if ( ! function_exists( 'generate_posted_on' ) ) :
/**
 * Prints HTML with meta information for the current post-date/time and author.
 */
function generate_posted_on() {

	if ( 'post' !== get_post_type() ) 
		return;
	
	$categories = get_the_category();
 
	if ( (! empty( $categories )) AND ($categories[0]->name == 'Krótkie pytania')) {

	$date = apply_filters( 'generate_post_date', true );
	$author = apply_filters( 'generate_post_author', true );
		
	$time_string = '<time class="entry-date published" datetime="%1$s" itemprop="datePublished">Odpowiedź z %2$s, %5$s</time>';
	if ( get_the_time( 'U' ) !== get_the_modified_time( 'U' ) )
		$time_string .= '<time class="updated" datetime="%3$s" itemprop="dateModified">%4$s</time>';

	$time_string = sprintf( $time_string,
		esc_attr( get_the_date( 'c' ) ),
		esc_html( get_the_date() ),
		esc_attr( get_the_modified_date( 'c' ) ),
		esc_html( get_the_modified_date() ),
		esc_attr( get_the_time() )
	);
	
	// If our date is enabled, show it
	if ( $date ) :
		printf( '<span class="posted-on">%1$s</span>',
			$time_string
		);
	endif;

	$zadajacy = get_post_meta( get_the_ID(), 'zadajacy', true );

	echo '. Pytanie nadesłał(a) <span class="zadajacy">' . $zadajacy . '</span>.';
	
	if ( ! post_password_required() && ( comments_open() || get_comments_number() ) ) {
		echo '<span class="comments-link">';
		comments_popup_link( __( 'Leave a comment', 'generatepress-child' ), __( '1 Comment', 'generatepress-child' ), __( '% Comments', 'generatepress-child' ) );
		echo '</span>';
	}
	}
else { //jeśli nie krótkie pytanie, to co?

	$date = apply_filters( 'generate_post_date', true );
	$author = apply_filters( 'generate_post_author', true );
		
	$time_string = '<time class="entry-date published" datetime="%1$s" itemprop="datePublished">Opublikowano %2$s, %5$s</time>';
	if ( get_the_time( 'U' ) !== get_the_modified_time( 'U' ) )
		$time_string .= '<time class="updated" datetime="%3$s" itemprop="dateModified">%4$s</time>';

	$time_string = sprintf( $time_string,
		esc_attr( get_the_date( 'c' ) ),
		esc_html( get_the_date() ),
		esc_attr( get_the_modified_date( 'c' ) ),
		esc_html( get_the_modified_date() ),
		esc_attr( get_the_time() )
	);
	
	// If our date is enabled, show it
	if ( $date ) :
		printf( '<span class="posted-on">%1$s</span>',
			$time_string
		);
	endif;
	
	/* // If our author is enabled, show it
	if ( $author ) :
		printf( ' <span class="byline">%1$s</span>',
			sprintf( '<span class="author vcard" itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author">%1$s <a class="url fn n" href="%2$s" title="%3$s" rel="author" itemprop="url"><span class="author-name" itemprop="name">%4$s</span></a></span>',
				__( 'by','generate'),
				esc_url( get_author_posts_url( get_the_author_meta( 'ID' ) ) ),
				esc_attr( sprintf( __( 'View all posts by %s', 'generate' ), get_the_author() ) ),
				esc_html( get_the_author() )
			)
		);
	endif; */

$categories_list = get_the_category_list( _x( ', ', 'Used between list items, there is a space after the comma.', 'generate' ) );
	if ( $categories_list ) {
		printf( ' w kategorii <span class="cat-links"><span class="screen-reader-text">%1$s </span>%2$s</span>.',
			_x( 'Categories', 'Used before category names.', 'generate' ),
			$categories_list
		);
	}

	if ( ! post_password_required() && ( comments_open() || get_comments_number() ) ) {
		echo '<span class="comments-link">';
		comments_popup_link( __( 'Leave a comment', 'generatepress-child' ), __( '1 Comment', 'generatepress-child' ), __( '% Comments', 'generatepress-child' ) );
		echo '</span>';
	}
}
}
endif;

if ( ! function_exists( 'generate_entry_meta' ) ) :
/**
 * Prints HTML with meta information for the categories, tags.
 *
 * @since 1.2.5
 */
function generate_entry_meta() 
{
	$categories = apply_filters( 'generate_show_categories', true );
	$tags = apply_filters( 'generate_show_tags', true );
	$comments = apply_filters( 'generate_show_comments', true );
	
	if ( 'post' == get_post_type() ) {

		$tags_list = get_the_tag_list( '', _x( ', ', 'Used between list items, there is a space after the comma.', 'generatepress' ) );
		if ( $tags_list && $tags ) {
			printf( '<span class="tags-links"><span class="screen-reader-text">%1$s </span>%2$s</span>',
				_x( 'Tags', 'Used before tag names.', 'generatepress' ),
				$tags_list
			);
		}
	}

}
endif;

if ( ! function_exists( 'generate_content_more' ) ) :
/**
 * Prints the read more HTML to post content using the more tag
 */

	add_filter( 'the_content_more_link', 'generate_content_more' );
	function generate_content_more( $more ) {
		$more_jump = apply_filters( 'generate_more_jump','#more-' . get_the_ID() );

	$kateg1 = get_the_category();
	$kateg = $kateg1[0]->name;

	if ($kateg == 'Krótkie pytania') {
		return '<p class="read-more-container"><a class="read-more content-read-more" href="'. get_permalink( get_the_ID() ) . $more_jump . '">' . 'Zobacz odpowiedź >>' . '</a></p>';
	} else {
		return '<p class="read-more-container"><a class="read-more content-read-more" href="'. get_permalink( get_the_ID() ) . $more_jump . '">' . 'Czytaj dalej >>' . '</a></p>';
	}
 	}
endif;

function show_question_difficulty() {

	$kateg1 = get_the_category();
	$kateg = $kateg1[0]->name;

	if ($kateg == 'Krótkie pytania') {

	print '<div class="trudnosc" title="Poziom trudności">';

	$trudnosc = get_post_meta( get_the_ID(), 'trudnosc', true );
	$gwiazd = 0;

	for (; $gwiazd < floor($trudnosc / 2); $gwiazd++) {
		echo '<i class="fa fa-star" aria-hidden="true"></i>';
	}

	if (($trudnosc % 2) == 1) {
		echo '<i class="fa fa-star-half-o" aria-hidden="true"></i>';
		$gwiazd++;
	}

	for (; ($gwiazd < 5); $gwiazd++) {
		echo '<i class="fa fa-star-o" aria-hidden="true"></i>';
	}

	print '</div>';
	}
}