ohmygord

Hey RobAley, thanks a lot for the tool recommendations... also big thanks for the person who suggested SONAR+PHP, will definitely look at that too.

I was planning on using phpdoc and xdebug, but haven't ever looked at XHGUI. Is it significantly different from xdebug? At first glance there seems to be a fair bit of overlap in terms of functionality.

Yes, I have often said that you should never, ever throw (significant amounts of) code away and start from scratch. I have worked on two bodies of legacy code before and more or less used most of the techniques discussed in the comments, but this is unprecented - for me - in both size and badness. Client and I have agreed that I will work for a month and then see where we stand... I'm hoping that after a month I will have a better feel for whats going on and can outline either a staged or complete rewrite.

Lots of great advice in here, has lifted my spirits a bit. Especially getting complete client buy in (which I have internalised but I guess haven't expressed, either to myself or the client).

Yes, by myself. The client so far has been understanding... they've already burnt through several contracting companies, and I think they're starting to understand what a mess it is. But still, they want to see serious progress within a month (eg. large number of bug fixes).