Now that we target PHP 5.5, some people are itching to make use of some new language features, like the new array syntax, e.g. https://gerrit.wikimedia.org/r/#/c/269745/.
Mass changes like this, or similar changes relating to coding style, tend to lead to controversy. I want to make sure we have a discussion about this here, to avoid having the argument over and over on any such patch.
Please give a quick PRO or CON response as a basis for discussion.
In essence, the discussion boils down to two conflicting positions:
PRO: do mass migration to the new syntax, style, or whatever, as soon as possible. This way, the codebase is in a consistent form, and that form is the one we agreed is the best for readability. Doing changes like this is gratifying, because it's low hanging fruit: it's easy to do, and has large visible impact (well ok, visible in the source).
CON: don't do mass migration to new syntax, only start using new styles and features when touching the respective bit of code anyway. The argument is here that touching many lines of code, even if it's just for whitespace changes, causes merge conflicts when doing backports and when rebasing patches. E.g. if we touch half the files in the codebase to change to the new array syntax, who is going to manually rebase the couple of hundred patches we have open?
As can be seen on the proposed patch I linked, several of the long term developers oppose mass changes like this. A quick round of feedback in the architecture committee draws a similar picture. However, perhaps there are compelling arguments for doing the mass migration that we haven't heard yet. So please give a quick PRO or CON, optionally with some rationale.
My personal vote is CON. No rebase hell please! Changing to the syntax doesn't buy us anything.
-- daniel