Introduce wp_trigger_error()

[azaozz]

Trac ticket: https://core.trac.wordpress.org/ticket/57686

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[azaozz]

TODO/TBD: Wondering if it's worth it to add a simple backtrace when WP_DEVELOPMENT_MODE is true. Tested with only printing function names, no args as they can be huge sometimes. The code for it would be like:

	if ( WP_DEVELOPMENT_MODE ) {
		// Output a simple backtrace.
		ob_start();
		debug_print_backtrace( DEBUG_BACKTRACE_IGNORE_ARGS );
		$backtrace = ob_get_contents();
		ob_end_clean();

		// This may be called very early. See above about use of `__()`.
		if ( function_exists( 'esc_html' ) ) {
			$backtrace = esc_html( $backtrace );
		}

		// Space it a bit for better readability.
		$backtrace = str_replace( "\n", "\n\n", $backtrace );

		echo '<p style="white-space: pre-wrap;">';
		echo $backtrace;
		echo '</p>';
	}

[hellofromtonya]

Why translate PHP errors / warnings / notices / deprecations?

[azaozz]

Good question. These are translated in doing_it_wrong, was just using that code as example.
As these errors are intended only for developers and not for the end users, translation is probably not needed.

[hellofromtonya]

Closing in favor of a wrapper approach in #5144, that was committed instead.