Hello Brian,

Guix shows me a different hash for 0.3.0 branch.  Is it OK?
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oleg@guixsd ~/src$ ./pre-inst-env guix build -S emacs-counsel-projectile
;;; note: source file /home/oleg/src/guix/gnu/packages/emacs-xyz.scm
;;;       newer than compiled /home/oleg/src/guix/gnu/packages/emacs-xyz.go
;;; note: source file /home/oleg/src/guix/gnu/packages/emacs-xyz.scm
;;;       newer than compiled /run/current-system/profile/lib/guile/2.2/site-ccache/gnu/packages/emacs-xyz.go
The following derivation will be built:
   /gnu/store/3dcdfi2c45n89c5ybpj6y7swf5qvzybd-emacs-counsel-projectile-0.3.0-checkout.drv
building /gnu/store/3dcdfi2c45n89c5ybpj6y7swf5qvzybd-emacs-counsel-projectile-0.3.0-checkout.drv...
environment variable `PATH' set to `/gnu/store/q09sy224qnxrp982z4xfaxi19721mjx8-gzip-1.9/bin:/gnu/store/ipx79bfj2mrc8npj7s3qi3zri11jfhaw-tar-1.30/bin'
Initialized empty Git repository in /gnu/store/8y2h0bn5pfqf5y90qdv7kpqmxxwn08yb-emacs-counsel-projectile-0.3.0-checkout/.git/
From https://github.com/ericdanan/counsel-projectile
 * tag               0.3.0      -> FETCH_HEAD
Note: checking out 'FETCH_HEAD'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by performing another checkout.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -b with the checkout command again. Example:

  git checkout -b <new-branch-name>

HEAD is now at d64e527 Release 0.3.0
r:sha256 hash mismatch for /gnu/store/8y2h0bn5pfqf5y90qdv7kpqmxxwn08yb-emacs-counsel-projectile-0.3.0-checkout:
  expected hash: 1a29f16m463d4jsd1m071483vhq3589djdq47mw800844n20irbd
  actual hash:   1inc4ndl0ysfwvxk4avbgpj4qi9rc93da6476a5c81xmwpsv8wmq
hash mismatch for store item '/gnu/store/8y2h0bn5pfqf5y90qdv7kpqmxxwn08yb-emacs-counsel-projectile-0.3.0-checkout'
build of /gnu/store/3dcdfi2c45n89c5ybpj6y7swf5qvzybd-emacs-counsel-projectile-0.3.0-checkout.drv failed
View build log at '/var/log/guix/drvs/3d/cdfi2c45n89c5ybpj6y7swf5qvzybd-emacs-counsel-projectile-0.3.0-checkout.drv.bz2'.
guix build: error: build of `/gnu/store/3dcdfi2c45n89c5ybpj6y7swf5qvzybd-emacs-counsel-projectile-0.3.0-checkout.drv' failed

oleg@guixsd ~/src$ git -C /tmp clone -b 0.3.0 https://github.com/ericdanan/counsel-projectile
Cloning into 'counsel-projectile'...
remote: Enumerating objects: 19, done.        
remote: Counting objects: 100% (19/19), done.        
remote: Compressing objects: 100% (13/13), done.        
remote: Total 568 (delta 10), reused 15 (delta 6), pack-reused 549        
Receiving objects: 100% (568/568), 244.61 KiB | 505.00 KiB/s, done.
Resolving deltas: 100% (356/356), done.
Note: checking out 'd64e5275c578a494102852c466a3696bde466739'.
[…]

oleg@guixsd ~/src$ guix hash -rx /tmp/counsel-projectile/guix
1inc4ndl0ysfwvxk4avbgpj4qi9rc93da6476a5c81xmwpsv8wmq
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Oleg.