Grant Proposal: Fixing Perl5 Core Bugs

David Mitchell has submitted a grant proposal, which if accepted would make use of a portion of the funding generously provided to TPF by

Before the Board votes on this proposal we would like to get feedback and endorsements from the Perl community. Please leave feedback in the comments or send email with your comments to karen at

Grant Title: Fixing perl5 core bugs

Name: David Mitchell

Amount Requested: $25,000


Recently, donated $50K for the "further development and
maintenance of the Perl programming language". I would like part of that
money to to be used to fund me for approximately six months to devote 50%
of my time fixing "hard" core perl5 bugs.

Benefits to the Perl Community

There are currently approximately 1200 open and 300 new bug reports in the
perl5 bug queue. Although some of these are of the "5.003_08 does not
build on platform X" variety, many are current: for example, almost 500 of
them were created after the release of 5.10.0. As the perl core has become
more and more gnarly, and the pool of experienced but active core hackers
has declined, these bugs are just piling up and not getting fixed,
especially the hard ones. With this funding, I would would be able to
devote serious time and effort to making a dent in this queue.

Note that unlike many large open source projects, perl has no paid
developers devoted to bug fixing.


Unusually for a TPF grant, there are not clear-cut deliverables for this
project. I intend to devote 500 hours of my time over the next six months
fixing perl core bugs. The net result will be a list of bug numbers that
have been diagnosed, and (hopefully) fixed. Because it's impossible to
predict in advance how difficult a bug is going to be to diagnose and fix
(or indeed whether it is even fixable), I can't commit in advance to a
fixed list of bugs that I will fix over the course of the grant. Nor is it
realistic to have a bounty per fixed bug; I would end up not getting
rewarded for time spent on difficult bugs, and conversely I would have a
strong incentive to cherry-pick easy bugs, defeating the purpose of the

Therefore, monitoring of my progress will become important (see below).

Project Details

I think this has been fully covered above.


Note that due to the length and scale of this project, it is suggested
that there be two project managers, who can spread the monitoring load
between them as they see fit.

Since this project is heavily based on hours worked and the monitoring
thereof, I would post a weekly summary on the p5p mailing list which
details, for each bug worked on that week, how many hours were spent on
diagnosis and fixes, plus any bug status changes. This frequent feedback
would allow the grant managers and active core developers (who will be
aware of any recent commits and other activity of mine) to observe whether
my claimed hours bear any relation to actual activity and results, and
thus allow early flagging of any concerns.

Missing two weekly reports in a row without prior notice would be grounds
for terminating the project.

Once per calendar month I would claim an amount equal to $50 x hours worked.
I would issue a report similar to the weekly ones, but summarizing the
whole month. The report would need to be signed off by one of the
project managers before I get paid. Note that this means I am paid
entirely in arrears.

At the time of my final claim, I would also produce a report summarising
the activity across the whole project period.

Also, (the "nuclear option"), I suggest that either of the project managers
be allowed, at any time, to inform the board that in their opinion the
project is failing badly, and that the TPF board may then, after allowing
me to present my side of things, to vote whether to terminate the project
at that point (i.e. to not pay me for any hours worked after I was first
informed that a manager had "raised the alarm").

To ensure that at there are at least some visible results for the hours
spent, I would be required have closed at least one bug per 20 hours
before being able to claim money for those hours. (I would hope to close
more bugs than that, but by setting a low baseline, I'm not tying my
hands, while still allowing TPF to have something visible for publicity
purposes during the interim.)

Project Schedule

I am available to start work on this project immediately.

The project is expected to take six months. I am self-employed, which
allows me a good deal of flexibility. By promising approximately 50% of my
time, this gives me the ability to continue with my existing commitments
to other clients, while deferring seeking new clients. As such, the weekly
hours I devote to perl are likely to be highly variable, but hopefully
averaging out to about 20 hours per week. If for some reason I find that I
have spent less than 500 hours at the end of the six months, then I will
continue the project until until the 500 hours been spent, with the
proviso that that the TPF board are free to terminate the project at any
time after the six months. Conversely, if I manage to devote more than 20
hours per week, then my monthly payments will be accordingly larger, and
the project will terminate early (once the 500 hours are spent).

Note that it is currently my intention that the after six months I will
apply for a further $25K extension, although there is no obligation for me
to do so, nor for TPF to approve it.


I'm a freelance UNIX sysadmin and programmer living in the UK. I have been
using perl since 1993, and have been fixing core perl 5 bugs since 2001.
I have had commit rights since 2003 and I was pumpking for the 5.10.1 perl

In short, I am one of only a handful of active people who understand large
parts of the perl internals and who can thus fix "hard" bugs.


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