So which is it that you think is better and more intuitive?
Fixed the XXX bug in YYY
Fix the XXX bug in YYY
Fixes the XXX bug in YYY
Fixing the XXX bug in YYY
Please provide your rationales. Note I am asking from your general perspective, meaning you should not try to associate this with your preferred svn/cvs tools or programming languages, but rather think of it as something that should/can be applied to any tools and programming languages.
I don't think it really matters. The purpose is to:
1) Convey what is or was being done, so bugs can be found easier, problems can be reverted easier, and generally be able to maintain the project easier.
2) Convey what tickets were fixed if any, so auditors (if they're used in you company can see what changes correspond to which tickets).
Lastly, if it's' already been fixed, "Fixing" doesn't make sense, and if you're still working on it, "Fixed" isn't correct.
I personally go with past tense ("fixed") since by the time I get to committing the bug is fixed (or I wouldn't be committing).
I think that writing about the current commit in present tense is a good idea, because it makes it more clear when you refer to prior commits in the past tense.
If it is a small commit I use present continuous:
Fixing bug 304
or
Adding comments
If it is a big commit, I do more of a change log:
"Fix bug X" is 2 characters shorter than "Fixed bug X".
And 3 shorter than "Fixing bug X".
From the point of view of writing-short-commit-messages, the present tense sometimes / usually saves a few characters?
Which I actually think matters a little little bit e.g. with Git's recommendation of less-than-50-chars-on-the-first-commit-message-line.
Also, less text --> done reading quicker?
IMHO if you want it to be descriptive without need to consider the context, then "Fixed" is definitely the only right variant.
Regarding the intuitiveness - if I look at some changelog I will definitely understand that you mean the bug fixed as I know the context in which the word is used, but my brain will catch it much more quickly if the word is written in this self-specifying way.
"Fixing" is the worst choice IMHO as it can be interpreted not only as describing what the patch does (is for) but as a bug status as well which would mean that it is being worked at and is not yet solved.