On commit access, patch review, and remaining healthy

[Ludovic Courtès]

Hello Guix!

Following on the theme of patch review, I did some stats with the
attached tools on commits since 1.3.0:

  • 20,489 commits were made since then;

  • 4,476 were commits pushed on behalf of a non-committer;

  • of these, half were pushed by 2 committers, out of 40ish.

Some conclusions we can draw:

  • We have a strong core development team, which I think is great
    compared to many free software projects.

    Perhaps the flip side of this is that we make too little space to
    newcomers.  (I feel we’re almost the opposite of a typical
    Git{Hub,Lab}-hosted project where drive-by contributions are common
    and long-term commitment is rare.)

  • Review work is severely lacking.  The manual reads (info "(guix)
    Commit Access"):

      […] the project keeps moving forward because committers not only push
      their own awesome changes, but also offer some of their time
      _reviewing_ and pushing other people’s changes.  As a committer,
      you’re welcome to use your expertise and commit rights to help
      other contributors, too!

    Yet, most committers don’t allocate time to review and push other
    people’s changes.

    Why aren’t we, committers, not doing more review/apply work?  Is it
    too intimidating?  Would having a documented review checklist help?

    If you’re not using Emacs, what actionable steps should we take with
    mumi and other tools to help you (Arun made several proposals in
    their Guix Days talk)?  If you are using Emacs, does debbugs.el have
    shortcomings that make it a problem to review patches?

  • We need to be able to renew committers.  There’s a process in place
    to remove, at least temporarily, committers that have been inactive
    for a year or more, and I think it’s good (info "(guix) Commit
    Access").

    Maybe we should also encourage committers who have “moved on” to let
    the project know so we have a clearer picture of who’s in—meaning
    available not just to commit their own occasional patches, but also
    to help other contributors.

    In addition to that, we need to encourage contributors who are not
    committers yet, which obviously means reviewing and applying their
    contributions in a timely fashion.  We need to grow prolific
    contributors into leadership positions to they can become committers
    and take part into this whole process.

In short, we need to break out of a potentially vicious circle where
active members don’t make the work that would allow newcomers to get
more involved, at the risk of burning out themselves.

Let’s make sure this project keeps striving for decades to come!  :-)

Thoughts?

Ludo’.

(use-modules (git)
             (git repository)
             (git reference)
             (git oid)
             (git tag)
             (git commit)
             (git structs)                        ;signature-email, etc.
             (guix git)
             (srfi srfi-1)
             (srfi srfi-26)
             (ice-9 match)
             (ice-9 vlist))

(define commit-author*
  (compose signature-name commit-author))
(define commit-committer*
  (compose signature-name commit-committer))

(define-syntax-rule (false-if-git-error exp)
  (catch 'git-error
    (lambda () exp)
    (const #f)))

(define* (fold-commits proc seed repo
                       #:key
                       (start (reference-target
                               (repository-head repo)))
                       end)
  "Call PROC on each commit of REPO, starting at START (an OID), and until
END if specified."
  (let loop ((commit (commit-lookup repo start))
             (result seed))
    (let ((parent (false-if-git-error (commit-parent commit))))
      (if parent
          (if (and end (oid=? (commit-id parent) end))
              (proc parent result)
              (loop parent (proc parent result)))
          result))))

(define (reviewers repo commits)
  "Return a list of review count/committer pairs."
  (define vhash
    (fold (lambda (commit result)
            (if (string=? (commit-author* commit)
                          (commit-committer* commit))
                result
                (vhash-cons (commit-committer* commit) #t
                            result)))
          vlist-null
          commits))

  (define committers
    (delete-duplicates
     (fold-commits (lambda (commit result)
                     (cons (commit-committer* commit)
                           result))
                   '()
                   repo)))

  (map (lambda (committer)
         (cons (vhash-fold* (lambda (_ count)
                              (+ 1 count))
                            0
                            committer
                            vhash)
               committer))
       committers))

(define (reviewer< r1 r2)
  (match r1
    ((count1 . name1)
     (match r2
       ((count2 . name2)
        (< count1 count2))))))

(define repo
  (repository-open "."))

(define commits
  (commit-difference (commit-lookup repo
                                    (reference-target (repository-head repo)))
                     (commit-lookup
                      repo
                      (tag-target-id
                       (tag-lookup
                        repo
                        (reference-target
                         (reference-lookup repo "refs/tags/v1.3.0")))))))