--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python/hg-merge.py	Mon Feb 13 16:22:59 2012 -0800
@@ -0,0 +1,127 @@
+#!/usr/bin/env python
+
+"""
+merge mercurial repositories
+
+Example:
+hg-merge.py --master http://hg.mozilla.org/build/talos http://hg.mozilla.org/build/pageloader#talos/pageloader
+"""
+
+import optparse
+import os
+import shutil
+import subprocess
+import sys
+import tempfile
+import urlparse
+try:
+    from subprocess import check_call as call
+except:
+    from subprocess import call
+
+def url2filename(url):
+    """gets a filename from a url"""
+    scheme, netloc, path, query, fragment = urlparse.urlsplit(url)
+    path = path.rstrip('/')
+    assert path and '/' in path
+    return path.split('/')[-1]
+
+def manifest(hgrepo):
+    """manifest of a local hg repository"""
+    process = subprocess.Popen(['hg', 'manifest'], cwd=hgrepo, stdout=subprocess.PIPE)
+    stdout, stderr = process.communicate()
+    assert not process.returncode
+    manifest = stdout.strip().splitlines()
+    return set(manifest)
+
+def merge(hgroot, repo, subpath=None):
+    """merge repo to hgroot at subpath (None for repository root)"""
+
+    # get a manifest of the current repository
+    root_manifest = manifest(hgroot)
+    toplevel_contents = os.listdir(hgroot)
+
+    # staging area
+    tempdir = tempfile.mkdtemp()
+    fd, tmpfile = tempfile.mkstemp()
+    os.close(fd)
+
+    exception = None
+    try:
+
+        # clone the repository to be merged in
+        call(['hg', 'clone', repo, tempdir])
+
+        # check manifest for conflicts
+        repo_manifest = manifest(tempdir)
+        assert repo_manifest, "Empty repository: %s" % repo
+        intersection = root_manifest.intersection(repo_manifest)
+        assert not intersection, "Overlap between %s and %s: %s" % (hgroot, repo, intersection)
+
+        # create a bundle
+        call(['hg', 'bundle', tmpfile, '--all'], cwd=tempdir)
+
+        # apply the bundle
+        call(['hg', 'unbundle', tmpfile], cwd=hgroot)
+        call(['hg', 'merge'], cwd=hgroot)
+
+        if subpath:
+            # move the new files to their new locations
+            for item in repo_manifest:
+                path = os.path.join(subpath, item)
+                fullpath = os.path.join(hgroot, path)
+                assert not os.path.exists(fullpath), "%s already exists" % fullpath
+                subdirectory = os.path.dirname(fullpath)
+                if not os.path.exists(subdirectory):
+                    os.makedirs(subdirectory)
+                call(['hg', 'mv', item, path], cwd=hgroot)
+            call(['hg', 'commit', '-m', 'merge %s to %s' % (repo, subpath)], cwd=hgroot)
+        else:
+            call(['hg', 'commit', '-m', 'merge in %s' % repo], cwd=hgroot)
+
+    except Exception, exception:
+        pass # reraise on cleanup
+
+    # cleanup
+    shutil.rmtree(tempdir)
+    os.remove(tmpfile)
+    if exception is not None:
+        raise exception
+
+def main(args=sys.argv[1:]):
+
+    # parse command line options
+    usage = "%prog [options] http://hg.example.com/repository/path#destination/path [...]"
+    parser = optparse.OptionParser(usage=usage, description=__doc__)
+    parser.add_option('-m', '--master', dest='master',
+                      help="use this as the master repository (new clone, otherwise use CWD)")
+    options, args = parser.parse_args(args)
+    if not args:
+        parser.print_help()
+        parser.exit()
+
+    if options.master:
+        # clone the new repository
+        directory = url2filename(options.master)
+        if os.path.exists(directory):
+            shutil.rmtree(directory)
+        call(['hg', 'clone', options.master])
+        hgroot = os.path.join(os.getcwd(), directory)
+    else:
+        # get the root of the repository
+        process = subprocess.Popen(['hg', 'root'], stdout=subprocess.PIPE)
+        hgroot, stderr = process.communicate()
+        hgroot = hgroot.strip()
+        if process.returncode:
+            sys.exit(1)
+    assert os.path.exists(hgroot) and os.path.isdir(hgroot), "%s not found" % hgroot
+
+    # get the other repos to add
+    for repo in args:
+        subpath = None
+        if '#' in repo:
+            repo, subpath = repo.rsplit('#', 1)
+        merge(hgroot, repo, subpath)
+
+if __name__ == '__main__':
+    main()