subrepo: do not push mercurial subrepos whose store is clean

subrepo: do not push mercurial subrepos whose store is clean

This patch stops mercurial from pushing unmodified subrepos. An unmodified
subrepo is one whose store is "clean" versus a given target subrepo.

Note that subrepos may have a clean store versus a target repo but not versus another. This patch handles this scenario by individually keeping track of the state of the store versus all push targets.

Tests will be added on the following revision.

--- a/mercurial/subrepo.py	Sat Feb 16 01:18:53 2013 +0100
+++ b/mercurial/subrepo.py	Sat Feb 16 01:21:40 2013 +0100
@@ -14,10 +14,19 @@
 
 nullstate = ('', '', 'empty')
 
+def _expandedabspath(path):
+    '''
+    get a path or url and if it is a path expand it and return an absolute path
+    '''
+    expandedpath = util.urllocalpath(util.expandpath(path))
+    u = util.url(expandedpath)
+    if not u.scheme:
+        path = util.normpath(os.path.abspath(u.path))
+    return path
 
 def _getstorehashcachename(remotepath):
     '''get a unique filename for the store hash cache of a remote repository'''
-    return util.sha1(remotepath).hexdigest()[0:12]
+    return util.sha1(_expandedabspath(remotepath)).hexdigest()[0:12]
 
 def _calcfilehash(filename):
     data = ''
@@ -475,10 +484,10 @@
         require a push to a given remote path.'''
         # sort the files that will be hashed in increasing (likely) file size
         filelist = ('bookmarks', 'store/phaseroots', 'store/00changelog.i')
-        yield '# %s\n' % remotepath
+        yield '# %s\n' % _expandedabspath(remotepath)
         for relname in filelist:
             absname = os.path.normpath(self._repo.join(relname))
-            yield '%s = %s\n' % (absname, _calcfilehash(absname))
+            yield '%s = %s\n' % (relname, _calcfilehash(absname))
 
     def _getstorehashcachepath(self, remotepath):
         '''get a unique path for the store hash cache'''
@@ -691,6 +700,12 @@
                 return False
 
         dsturl = _abssource(self._repo, True)
+        if not force:
+            if self.storeclean(dsturl):
+                self._repo.ui.status(
+                    _('no changes made to subrepo %s since last push to %s\n')
+                    % (subrelpath(self), dsturl))
+                return None
         self._repo.ui.status(_('pushing subrepo %s to %s\n') %
             (subrelpath(self), dsturl))
         other = hg.peer(self._repo, {'ssh': ssh}, dsturl)