build: Add GUIX_GIT_KEYRING variable for make authenticate.

* Makefile.am (GUIX_GIT_KEYRING): New variable.
(authenticate): Use GUIX_GIT_KEYRING to select the keyring branch
reference.
* doc/contributing.texi (Building from Git): Add an example about the
use of GUIX_GIT_KEYRING.

diff --git a/Makefile.am b/Makefile.am
index c509562..e6cef9e 100644 (file)
--- a/Makefile.am
+++ b/Makefile.am
@@ -666,9 +666,11 @@ channel_intro_commit = 9edb3f66fd807b096b48283debdcddccfea34bad
 channel_intro_signer = BBB0 2DDF 2CEA F6A8 0D1D  E643 A2A0 6DF2 A33A 54FA
 
 # Authenticate the current Git checkout by checking signatures on every commit.
+GUIX_GIT_KEYRING = origin/keyring
 authenticate:
        $(AM_V_at)echo "Authenticating Git checkout..." ;       \
        guix git authenticate                                   \
+           --keyring=$(GUIX_GIT_KEYRING)                       \
            --cache-key=channels/guix --stats                   \
            "$(channel_intro_commit)" "$(channel_intro_signer)"
 

diff --git a/doc/contributing.texi b/doc/contributing.texi
index 26a4627..d3f6325 100644 (file)
--- a/doc/contributing.texi
+++ b/doc/contributing.texi
@@ -140,6 +140,16 @@ make authenticate
 
 The first run takes a couple of minutes, but subsequent runs are faster.
 
+Or, when your configuration for your local Git repository doesn't match
+the default one, you can provide the reference for the @code{keyring}
+branch through the variable @code{GUIX_GIT_KEYRING}.  The following
+example assumes that you have a Git remote called @samp{myremote}
+pointing to the official repository:
+
+@example
+make authenticate GUIX_GIT_KEYRING=myremote/keyring
+@end example
+
 @quotation Note
 You are advised to run @command{make authenticate} after every
 @command{git pull} invocation.  This ensures you keep receiving valid