1 files changed, 11 insertions, 6 deletions
diff --git a/acid/acid-source b/acid/acid-source
index 29b1516..351d3d0 100755
--- a/acid/acid-source
+++ b/acid/acid-source
@@ -12,8 +12,8 @@
 # The caller should cache this hash value upon successful deployment.
 #
 # If a new version of the file tree is checked out, this file exits with code 1,
-# otherwise a stale success exits with 0.  On any error, no hash is printed, and
-# we exit with 2.
+# otherwise a stale success exits with 0.  On any error, the null hash is
+# printed, and we exit with 2.
 
 gethash() {
     git for-each-ref \
@@ -23,16 +23,21 @@ gethash() {
         "$1" # pattern
 }
 
+fail() {
+    echo "$NULL_HASH"
+    exit 2
+}
+
 cd "$CYCHE_SERVICE_DIR"
 
 # For <name>, limit to a-z, 0-9, -, _
 if ! echo "$1" | grep -Eq '^[-_a-z0-9]*$'; then
     echo "Bad service name: $1" >&2
-    exit 2
+    fail
 fi
 
 if ! [ -d "$1" ]; then
-    git clone "$2" "$1" >&2 || exit 2
+    git clone "$2" "$1" >&2 || fail
     touch "$1/.git/previous_hash"
     touch "$1/.git/previous_slug"
 fi
@@ -40,14 +45,14 @@ fi
 cd "$1"
 
 git remote set-url origin "$2" >&2 # pick up url changes
-git fetch --all --prune >&2 || exit 2
+git fetch --all --prune >&2 || fail
 
 prev=$(cat '.git/previous_hash')
 next=$(gethash "$3")
 
 if [ -z "$next" ]; then
     echo "No refs match $3" >&2
-    exit 2
+    fail
 fi
 
 echo "$next"