2010/9/6 Aryeh Gregor Simetrical+wikilist@gmail.com:
Then you have to hope that the bug still occurs. Probably it will, but you never know. Plus, it would be nice if there weren't that extra step. Of course, even if they de-minified things, you'd still have no comments and so on, but at least the line number would mean something.
Actually, the line number would not mean a great deal because the scripts would still be combined, comments frequently take up entire lines and the deminifier cannot account for blank lines, statements broken over multiple lines, or multiple statements on one line. All this means it's impossible to map the line number to a source line and file, although I agree it does map it to a statement: someone else can add a breakpoint at the same line of the same combined+minified output (provided they're also hitting the same load.php URL) and have that break at the exact statement the reporter got their error on.
But all that is just theorizing about deminifying debuggers, which I don't think exist right now. The only thing we can do in practice is change the environment to remove the impediments to debugging we introduced and hope that doesn't make any bugs go away. We do this not only by obtaining each module's JS unminified in a separate request (unfortunately, we can't request CSS style sheets separately for dynamically requested modules because the technique needed for this is not as widely supported), but also by ensuring that all manipulation of JS and CSS we do (such as wrapping JS in a mediaWiki.loader.implement() call, direction flipping in CSS and image embedding in CSS) don't introduce or remove any lines, thereby preserving line numbers.
Roan Kattouw (Catrope)