[PATCH 0/2] Add mercurial-commitsigs and some changes to Mercurial.

[Xinglu Chen <public@yoctocell.xyz>]

The first patch adds the commitsigs extension for Mercurial, it allows
users to sign Mercurial changesets (equivalent to Git commits) with
GnuPG or OpenSSL.

The second patch adds PYTHONPATH to the ‘native-search-paths’ field of
Mercurial, this allows Mercurial to automatically find third-party
extensions (like commitsigs) installed in
/gnu/store/...-profile/lib/python3.8/site-packages/hgext3rd.  By
default, it only looks at
/gnu/store/...-mercurial/lib/python3.8/site-packages/hgext3rd.

However, I am not sure this is the best approach since it messes with
PYTHONPATH, AFAIK there is no such things as a HGEXTENSIONS variable I
could set.  Another problem is that I have to hardcode “python3.8”, this
would obviously have to be updated if the default Python version gets
updated.  I did try to do something like this:

#+begin_src scheme
(string-append
  "lib/python"
  (string-join
    (drop-right (string-split (package-version python) #\.) 1)
    ".")
  "/site-packages/hgext3rd")
#+end_src

but it just gave me a confusing error message when trying to build it;
it worked fine if I hit {C-x C-e} in Emacs, though.

What we could do instead is to delegate the work of installing Mercurial
extensions to Guix Home[1] (I am currently working on adding a service
for Mercurial[2]) and add a ‘mercurial-extension-file-path’ key to the
‘properties’ field of Mercurial extensions so Guix Home can tell
Mercurial where to find the extension by the relevant lines in hgrc.  We
could have a package definition like this:

#+begin_src scheme
(package
  (name "mercurial-commitsigs")
  ...
  (properties
   '((mercurial-extension-file-path . "commitsigs.py"))))
#+end_src

hgrc:

#+begin_src
[extensions]
commitsigs = /gnu/store/...-mercurial-commitsigs/commitsigs.py
#+end_src

[1]: https://yhetil.org/guix-devel/878s6u2pco.fsf@trop.in/
[2]: https://lists.sr.ht/~abcdw/rde-devel/patches/22421

Xinglu Chen (2):
  gnu: Add mercurial-commitsigs.
  gnu: mercurial: Add PYTHONPATH to ‘native-search-paths’.

 gnu/packages/version-control.scm | 68 ++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)


base-commit: aa7eeabe9a782afc2535581298990050d16b1895
-- 
2.31.1