sqliterevmap: break ".hashes()" cycle in a safer way The `fromsvn()` revset implementation could cause weakref error when using sqliterevmap like: File "hgsubversion/util.py", line 357, in <lambda> return subset.filter(lambda r: tonode(r) in hashes) File "hgsubversion/maps.py", line 542, in __contains__ return self.get(key) != None File "hgsubversion/maps.py", line 533, in get for row in self.revmap._query( ReferenceError: weakly-referenced object no longer exists Basically the seemingly harmless assignment could break surprisingly: # dangerous: `hashes` does not have a reference of `meta.revmap` and may # become unavailable after `meta`, `revmap` being released by refcount. hashes = meta.revmap.hashes() The above syntax is nice to support while avoiding cycles is also nice. This patch removes `revmap._hashes` so the revmap no longer owns a reference of a `ReverseRevMap` object so the `ReverseRevMap` object no longer needs to use weakref for `self.revmap`. This could actually be caught by `comprehensive/test_sqlite_revmap.py`. I was not careful enough verifying the "fromsvn()" patch.

import test_util

import unittest

from mercurial import ui

from hgsubversion import wrappers

expected_diff_output = '''Index: alpha
===================================================================
--- alpha\t(revision 3)
+++ alpha\t(working copy)
@@ -1,1 +1,3 @@
-file: alpha
+alpha
+
+added line
Index: foo
===================================================================
new file mode 100644
--- foo\t(revision 0)
+++ foo\t(working copy)
@@ -0,0 +1,1 @@
+This is missing a newline.
\ No newline at end of file
'''

class DiffTests(test_util.TestBase):
    def test_diff_output(self):
        self._load_fixture_and_fetch('two_revs.svndump')
        self.commitchanges([('foo', 'foo', 'This is missing a newline.'),
                            ('alpha', 'alpha', 'alpha\n\nadded line\n'),
                            ])
        u = test_util.testui()
        u.pushbuffer()
        wrappers.diff(lambda x, y, z: None, u, self.repo, svn=True)
        self.assertEqual(u.popbuffer(), expected_diff_output)