The plaintext error responses for AJAX requests in 1.4 drop a lot of the stack trace context that was included in the HTML responses pre-1.4. Tools like the network response 'Preview' viewer in Chrome make it easy to navigate the HTML response to drill down into the richer context it provides. This patch maintains the 1.4 default but enables the response to be configured to use the original behavior.
Added DEBUG_PLAINTEXT_AJAX_ERROR_MESSAGES setting to customize error …
Please be aware that pull requests won't be merged without a corresponding ticket in Trac (specifically, we need an excellent reason to add yet another setting).
Here's a Trac ticket for it:
Thanks :) Sorry, we still need to figure out some bits of our ticket management processes after the move to GitHub.
I'm closing this particular pull request, as Dave and I have discussed on Trac that a different approach would be better.