2 files changed, 61 insertions, 1 deletions
diff --git a/git_remote_helpers/git/importer.py b/git_remote_helpers/git/importer.py
index 02a719ac0..5c6b595e1 100644
--- a/git_remote_helpers/git/importer.py
+++ b/git_remote_helpers/git/importer.py
@@ -1,7 +1,7 @@
 import os
 import subprocess
 
-from git_remote_helpers.util import check_call
+from git_remote_helpers.util import check_call, check_output
 
 
 class GitImporter(object):
@@ -16,6 +16,18 @@ class GitImporter(object):
 
         self.repo = repo
 
+    def get_refs(self, gitdir):
+        """Returns a dictionary with refs.
+        """
+        args = ["git", "--git-dir=" + gitdir, "for-each-ref", "refs/heads"]
+        lines = check_output(args).strip().split('\n')
+        refs = {}
+        for line in lines:
+            value, name = line.split(' ')
+            name = name.strip('commit\t')
+            refs[name] = value
+        return refs
+
     def do_import(self, base):
         """Imports a fast-import stream to the given directory.
 
@@ -32,9 +44,23 @@ class GitImporter(object):
         if not os.path.exists(dirname):
             os.makedirs(dirname)
 
+        refs_before = self.get_refs(gitdir)
+
         args = ["git", "--git-dir=" + gitdir, "fast-import", "--quiet", "--export-marks=" + path]
 
         if os.path.exists(path):
             args.append("--import-marks=" + path)
 
         check_call(args)
+
+        refs_after = self.get_refs(gitdir)
+
+        changed = {}
+
+        for name, value in refs_after.iteritems():
+            if refs_before.get(name) == value:
+                continue
+
+            changed[name] = value
+
+        return changed
diff --git a/git_remote_helpers/util.py b/git_remote_helpers/util.py
index 1652c65c8..fbbb01b14 100644
--- a/git_remote_helpers/util.py
+++ b/git_remote_helpers/util.py
@@ -175,6 +175,40 @@ def check_call(*popenargs, **kwargs):
     return 0
 
 
+# from python2.7:subprocess.py
+def check_output(*popenargs, **kwargs):
+    r"""Run command with arguments and return its output as a byte string.
+
+    If the exit code was non-zero it raises a CalledProcessError.  The
+    CalledProcessError object will have the return code in the returncode
+    attribute and output in the output attribute.
+
+    The arguments are the same as for the Popen constructor.  Example:
+
+    >>> check_output(["ls", "-l", "/dev/null"])
+    'crw-rw-rw- 1 root root 1, 3 Oct 18  2007 /dev/null\n'
+
+    The stdout argument is not allowed as it is used internally.
+    To capture standard error in the result, use stderr=STDOUT.
+
+    >>> check_output(["/bin/sh", "-c",
+    ...               "ls -l non_existent_file ; exit 0"],
+    ...              stderr=STDOUT)
+    'ls: non_existent_file: No such file or directory\n'
+    """
+    if 'stdout' in kwargs:
+        raise ValueError('stdout argument not allowed, it will be overridden.')
+    process = subprocess.Popen(stdout=subprocess.PIPE, *popenargs, **kwargs)
+    output, unused_err = process.communicate()
+    retcode = process.poll()
+    if retcode:
+        cmd = kwargs.get("args")
+        if cmd is None:
+            cmd = popenargs[0]
+        raise subprocess.CalledProcessError(retcode, cmd)
+    return output
+
+
 def file_reader_method (missing_ok = False):
     """Decorator for simplifying reading of files.