While working on the bug 'Changing package source URLs from git:// to
https://' [0], I noticed an issue with the sources for guile-emacs.

We currently fetch this source code over the unauthenticated GIT
protocol. It is also available over HTTPS. However, these two protocols
are returning different Git repos for some reason. For example, with the
diff shown below [1]:

------
% ./pre-inst-env guix build -S --no-grafts --no-substitutes guile-emacs
The following derivation will be built:
   /gnu/store/1fwh26ssbzkw38k2ih3cvmfk7zch2bdb-git-checkout.drv
@ build-started /gnu/store/1fwh26ssbzkw38k2ih3cvmfk7zch2bdb-git-checkout.drv - x86_64-linux /var/log/guix/drvs/1f//wh26ssbzkw38k2ih3cvmfk7zch2bdb-git-checkout.drv.bz2
Cloning into '/gnu/store/jlkhs6ypnlvbzl4jassp871v0z86199y-git-checkout'...
fatal: reference is not a tree: 41120e0f595b16387eebfbf731fff70481de1b4b
environment variable `PATH' unset
r:sha256 hash mismatch for output path `/gnu/store/jlkhs6ypnlvbzl4jassp871v0z86199y-git-checkout'
  expected: 0lvcvsz0f4mawj04db35p1dvkffdqkz8pkhc0jzh9j9x2i63kcz6
  actual:   1qish7cgck6brag4i4bgy31nzjrylwgmiai04ddzl5z2025a3shd
@ build-failed /gnu/store/1fwh26ssbzkw38k2ih3cvmfk7zch2bdb-git-checkout.drv - 1 r:sha256 hash mismatch for output path `/gnu/store/jlkhs6ypnlvbzl4jassp871v0z86199y-git-checkout'
  expected: 0lvcvsz0f4mawj04db35p1dvkffdqkz8pkhc0jzh9j9x2i63kcz6
  actual:   1qish7cgck6brag4i4bgy31nzjrylwgmiai04ddzl5z2025a3shd
guix build: error: build failed: build of `/gnu/store/1fwh26ssbzkw38k2ih3cvmfk7zch2bdb-git-checkout.drv' failed
------

[0]
https://bugs.gnu.org/27778

[1]
diff --git a/gnu/packages/emacs.scm b/gnu/packages/emacs.scm
index 43de13057..9d44d82ab 100644
--- a/gnu/packages/emacs.scm
+++ b/gnu/packages/emacs.scm
@@ -262,7 +262,7 @@ editor (without an X toolkit)" )
     (source (origin
               (method git-fetch)
               (uri (git-reference
-                    (url "git://git.hcoop.net/git/bpt/emacs.git")
+                    (url "https://git.hcoop.net/git/bpt/emacs.git")
                     (commit "41120e0f595b16387eebfbf731fff70481de1b4b")))
               (sha256