[PATCH] atomictempfile: make close() consistent with other file-like objects

Greg Ward greg-hg at gerg.ca
Wed Aug 24 19:21:33 CDT 2011


# HG changeset patch
# User Greg Ward <greg at gerg.ca>
# Date 1314230781 14400
# Node ID 21ed0d84367a43dde677cff6f2391e7ea2e9bb48
# Parent  ef43610a4cce7b8810af95fab1591adf821c3669
atomictempfile: make close() consistent with other file-like objects.

The usual contract is that close() makes your writes permanent, so
atomictempfile's use of close() to *discard* writes (and rename() to
keep them) is rather unexpected. Thus, change it so close() makes
things permanent and add a new discard() method to throw them away.
discard() is only used internally, in __del__(), to ensure that writes
are discarded when an atomictempfile object goes out of scope.

I audited mercurial.*, hgext.*, and ~80 third-party extensions, and
found no one using the existing semantics of close() to discard
writes, so this should be safe.

Up for discussion: I also left in a rename() method that issues a
deprecation warning and calls close(). This makes the transition a
little easier at the cost of crufting up the code. Opinions?

diff --git a/hgext/mq.py b/hgext/mq.py
--- a/hgext/mq.py
+++ b/hgext/mq.py
@@ -1492,7 +1492,7 @@
                 n = repo.commit(message, user, ph.date, match=match,
                                 force=True)
                 # only write patch after a successful commit
-                patchf.rename()
+                patchf.close()
                 self.applied.append(statusentry(n, patchfn))
             except:
                 ctx = repo[cparents[0]]
diff --git a/mercurial/archival.py b/mercurial/archival.py
--- a/mercurial/archival.py
+++ b/mercurial/archival.py
@@ -195,7 +195,7 @@
             return
         f = self.opener(name, "w", atomictemp=True)
         f.write(data)
-        f.rename()
+        f.close()
         destfile = os.path.join(self.basedir, name)
         os.chmod(destfile, mode)
 
diff --git a/mercurial/bookmarks.py b/mercurial/bookmarks.py
--- a/mercurial/bookmarks.py
+++ b/mercurial/bookmarks.py
@@ -90,7 +90,7 @@
         file = repo.opener('bookmarks', 'w', atomictemp=True)
         for refspec, node in refs.iteritems():
             file.write("%s %s\n" % (hex(node), encoding.fromlocal(refspec)))
-        file.rename()
+        file.close()
 
         # touch 00changelog.i so hgweb reloads bookmarks (no lock needed)
         try:
@@ -121,7 +121,7 @@
     try:
         file = repo.opener('bookmarks.current', 'w', atomictemp=True)
         file.write(encoding.fromlocal(mark))
-        file.rename()
+        file.close()
     finally:
         wlock.release()
     repo._bookmarkcurrent = mark
diff --git a/mercurial/dirstate.py b/mercurial/dirstate.py
--- a/mercurial/dirstate.py
+++ b/mercurial/dirstate.py
@@ -453,7 +453,7 @@
             write(e)
             write(f)
         st.write(cs.getvalue())
-        st.rename()
+        st.close()
         self._lastnormaltime = None
         self._dirty = self._dirtypl = False
 
diff --git a/mercurial/hbisect.py b/mercurial/hbisect.py
--- a/mercurial/hbisect.py
+++ b/mercurial/hbisect.py
@@ -150,7 +150,7 @@
         for kind in state:
             for node in state[kind]:
                 f.write("%s %s\n" % (kind, hex(node)))
-        f.rename()
+        f.close()
     finally:
         wlock.release()
 
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -521,7 +521,7 @@
             for label, nodes in branches.iteritems():
                 for node in nodes:
                     f.write("%s %s\n" % (hex(node), encoding.fromlocal(label)))
-            f.rename()
+            f.close()
         except (IOError, OSError):
             pass
 
diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -946,9 +946,9 @@
             e = self._io.packentry(self.index[i], self.node, self.version, i)
             fp.write(e)
 
-        # if we don't call rename, the temp file will never replace the
+        # if we don't call close, the temp file will never replace the
         # real index
-        fp.rename()
+        fp.close()
 
         tr.replace(self.indexfile, trindex * self._io.size)
         self._chunkclear()
diff --git a/mercurial/simplemerge.py b/mercurial/simplemerge.py
--- a/mercurial/simplemerge.py
+++ b/mercurial/simplemerge.py
@@ -445,7 +445,7 @@
         out.write(line)
 
     if not opts.get('print'):
-        out.rename()
+        out.close()
 
     if m3.conflicts:
         if not opts.get('quiet'):
diff --git a/mercurial/store.py b/mercurial/store.py
--- a/mercurial/store.py
+++ b/mercurial/store.py
@@ -345,7 +345,7 @@
         fp = self.opener('fncache', mode='wb', atomictemp=True)
         for p in self.entries:
             fp.write(encodedir(p) + '\n')
-        fp.rename()
+        fp.close()
         self._dirty = False
 
     def add(self, fn):
diff --git a/mercurial/tags.py b/mercurial/tags.py
--- a/mercurial/tags.py
+++ b/mercurial/tags.py
@@ -287,6 +287,6 @@
         cachefile.write("%s %s\n" % (hex(node), name))
 
     try:
-        cachefile.rename()
+        cachefile.close()
     except (OSError, IOError):
         pass
diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -71,6 +71,8 @@
 unlinkpath = platform.unlinkpath
 username = platform.username
 
+import warnings
+
 # Python compatibility
 
 def sha1(s):
@@ -745,11 +747,10 @@
     '''writeable file object that atomically updates a file
 
     All writes will go to a temporary copy of the original file. Call
-    rename() when you are done writing, and atomictempfile will rename
-    the temporary copy to the original name, making the changes visible.
-
-    Unlike other file-like objects, close() discards your writes by
-    simply deleting the temporary file.
+    close() when you are done writing, and atomictempfile will rename
+    the temporary copy to the original name, making the changes
+    visible. If the object is destroyed without being closed, all your
+    writes are discarded.
     '''
     def __init__(self, name, mode='w+b', createmode=None):
         self.__name = name      # permanent name
@@ -761,12 +762,17 @@
         self.write = self._fp.write
         self.fileno = self._fp.fileno
 
-    def rename(self):
+    def close(self):
         if not self._fp.closed:
             self._fp.close()
             rename(self._tempname, localpath(self.__name))
 
-    def close(self):
+    def rename(self):
+        warnings.warn('atomictempfile.rename() replaced by close()',
+                      DeprecationWarning, 2)
+        self.close()
+
+    def discard(self):
         if not self._fp.closed:
             try:
                 os.unlink(self._tempname)
@@ -776,7 +782,7 @@
 
     def __del__(self):
         if safehasattr(self, '_fp'): # constructor actually did something
-            self.close()
+            self.discard()
 
 def makedirs(name, mode=None):
     """recursive directory creation with parent mode inheritance"""
diff --git a/tests/test-atomictempfile.py b/tests/test-atomictempfile.py
--- a/tests/test-atomictempfile.py
+++ b/tests/test-atomictempfile.py
@@ -12,22 +12,21 @@
     assert basename in glob.glob('.foo-*')
 
     file.write('argh\n')
-    file.rename()
+    file.close()
 
     assert os.path.isfile('foo')
     assert basename not in glob.glob('.foo-*')
     print 'OK'
 
-# close() removes the temp file but does not make the write
-# permanent -- essentially discards your work (WTF?!)
-def test2_close():
+# discard() removes the temp file without making the write permanent
+def test2_discard():
     if os.path.exists('foo'):
         os.remove('foo')
     file = atomictempfile('foo')
     (dir, basename) = os.path.split(file._tempname)
 
     file.write('yo\n')
-    file.close()
+    file.discard()
 
     assert not os.path.isfile('foo')
     assert basename not in os.listdir('.')
@@ -45,5 +44,5 @@
 
 if __name__ == '__main__':
     test1_simple()
-    test2_close()
+    test2_discard()
     test3_oops()


More information about the Mercurial-devel mailing list