Rust uses the train release model which releases every 6 weeks [1]. It's definitely possible for someone to have an open PR for a year that's not in this list. I'm pretty sure this list is generated by running `git log --format='%aN' 1.12.0..1.13.0 | sort -u`.
I think what's going on here is a rather specific misinterpretation on one or both your parts of what "contributed" means in this context.
If contributed is interpreted to mean "code was merged" not "work was done" then the period is a fairly static 6 weeks, but there's really no reason to be astonished about how many people were involved, as it could contain work from multiple months ago.
If contributed is interpreted to mean "work was done" then the number of people that contributed in this period compared to some other will have more meaning.
I think OJFord is working from the second interpretation.
Yes, it means "code was merged." (Though it's not a particularly large number of contributors, the last release had 176, and the release before that 126.)
This is actually something I'm kinda sad about; I want to get better at representing work in a broader way. For example, get a patch into Cargo, but not rustc? You're not on this list. I don't like it. Working on it though...
No, I'm assuming that the number of contributors is the number of people who's contributions - code - was merged into this release.
I'm disputing the six weeks figure by assuming exactly what you outline above - that 'work done' is different from 'code merged' - so contributors may well have produced the work over a period of a year or more, and it just happens that those contributions came together for this release
Anyway, it's not really important, I didn't mean for this to descend so far - regardless of the time frame it's fantastic that so many are contributing to the project :)
My point is just that they may have produced the patch outside of the six week period. When it makes the release is somewhat arbitrary, and out of the contributor's control.
Regardless, as I said below, it's great that so many people are contributing whatever the time frame :)
Someone could open a PR today and not see it merged for a year, surely?