Split brain: Better tag format filtering

The code only makes tag formats `old' and `new'.  Make it easier to
add a new tag format config item entry later.

No functional change with existing configurations.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

1 files changed, 4 insertions, 1 deletions

diff --git a/dgit b/dgit
index 216a9c3..5dfd97c 100755
--- a/dgit
+++ b/dgit
@@ -534,6 +534,9 @@ our %defcfg = ('dgit.default.distro' => 'debian',
 	       'dgit.default.archive-query' => 'madison:',
 	       'dgit.default.sshpsql-dbname' => 'service=projectb',
 	       'dgit.default.dgit-tag-format' => 'old,new,maint',
+	       # old means "repo server accepts pushes with old dgit tags"
+	       # new means "repo server accepts pushes with new dgit tags"
+	       # maint means "repo server accepts split brain pushes"
 	       'dgit-distro.debian.archive-query' => 'ftpmasterapi:',
 	       'dgit-distro.debian.git-check' => 'url',
 	       'dgit-distro.debian.git-check-suffix' => '/info/refs',
@@ -1194,7 +1197,7 @@ sub select_tagformat () {
     die 'bug' if $tagformatfn && $tagformat_want;
     # ... $tagformat_want assigned after previous select_tagformat
 
-    my (@supported) = grep { $_ ne 'maint' } access_cfg_tagformats();
+    my (@supported) = grep { $_ =~ m/^(?:old|new)$/ } access_cfg_tagformats();
     printdebug "select_tagformat supported @supported\n";
 
     $tagformat_want //= [ $supported[0], "distro access configuration", 0 ];