Merge remote-tracking branch 'origin/samthursfield/ref-access-fixes'

1 files changed, 9 insertions, 4 deletions

diff --git a/morphlib/git.py b/morphlib/git.py
index 5862ef9b..b3dd2c45 100644
--- a/morphlib/git.py
+++ b/morphlib/git.py
@@ -221,7 +221,12 @@ def clone_into(runcmd, srcpath, targetpath, ref=None):
     else:
         runcmd(['git', 'clone', '-b', ref, srcpath, targetpath])
 
-def find_first_ref(runcmd, gitdir, ref):
-    '''Find the *first* ref match and returns its sha1.'''
-    return runcmd(['git', 'show-ref', ref],
-                  cwd=gitdir).split("\n")[0].split(" ")[0]
+def is_valid_sha1(ref):
+    '''Checks whether a string is a valid SHA1.'''
+
+    valid_chars = 'abcdefABCDEF0123456789'
+    return len(ref) == 40 and all([x in valid_chars for x in ref])
+
+def rev_parse(runcmd, gitdir, ref):
+    '''Find the sha1 for the given ref'''
+    return runcmd(['git', 'rev-parse', ref], cwd=gitdir)[0:40]