[PATCH 1 of 2 STABLE] repoview: make propertycache.setcache compatible with repoview

[pierre-yves.david at ens-lyon.org]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at ens-lyon.org>
# Date 1380544571 -7200
#      Mon Sep 30 14:36:11 2013 +0200
# Branch stable
# Node ID 365d4888627295bb0368d658224cb9900fdcb6f7
# Parent  4d2bea6604d3bfb34860590fbb6e302cbf273f98
repoview: make propertycache.setcache compatible with repoview

Propertycache used standard attribute assignment. In the repoview case, this
assignment was forwarded to the unfiltered repo. This result in:
(1) unfiltered repo got a potentially wrong cache value,
(2) repoview never reused the cached value.

This patch replaces the standard attribute assignment by an assignment to
`objc.__dict__` which will bypass the `repoview.__setattr__`. This will not
affects other `propertycache` users and it is actually closer to the semantic we
need.

The interaction of `propertycache` and `repoview` are now tested in a python
test file.

diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -277,11 +277,12 @@ class propertycache(object):
         result = self.func(obj)
         self.cachevalue(obj, result)
         return result
 
     def cachevalue(self, obj, value):
-        setattr(obj, self.name, value)
+        # __dict__ assigment required to bypass __setattr__ (eg: repoview)
+        obj.__dict__[self.name] = value
 
 def pipefilter(s, cmd):
     '''filter string S through command CMD, returning its output'''
     p = subprocess.Popen(cmd, shell=True, close_fds=closefds,
                          stdin=subprocess.PIPE, stdout=subprocess.PIPE)
diff --git a/tests/test-propertycache.py b/tests/test-propertycache.py
new file mode 100644
--- /dev/null
+++ b/tests/test-propertycache.py
@@ -0,0 +1,94 @@
+"""test behavior of propertycache and unfiltered propertycache
+
+The repoview overlay is quite complexe. We test the behavior of
+property cache of both localrepo and repoview to prevent
+regression."""
+
+import os, subprocess
+import mercurial.localrepo
+import mercurial.repoview
+import mercurial.util
+import mercurial.hg
+import mercurial.ui as uimod
+
+
+# create some special property cache that trace they call
+
+calllog = []
+ at mercurial.util.propertycache
+def testcachedfoobar(repo):
+    name = repo.filtername
+    if name is None:
+        name = ''
+    val = len(name)
+    calllog.append(val)
+    return val
+
+#plug them on repo
+mercurial.localrepo.localrepository.testcachedfoobar = testcachedfoobar
+
+
+# create an empty repo. and instanciate it. It is important to run
+# those test on the real object to detect regression.
+repopath = os.path.join(os.environ['TESTTMP'], 'repo')
+subprocess.check_call(['hg', 'init', repopath])
+ui = uimod.ui()
+repo = mercurial.hg.repository(ui, path=repopath).unfiltered()
+
+
+print ''
+print '=== property cache ==='
+print ''
+print 'calllog:', calllog
+print 'cached value (unfiltered):',
+print vars(repo).get('testcachedfoobar', 'NOCACHE')
+
+print ''
+print '= first access on unfiltered, should do a call'
+print 'access:', repo.testcachedfoobar
+print 'calllog:', calllog
+print 'cached value (unfiltered):',
+print vars(repo).get('testcachedfoobar', 'NOCACHE')
+
+print ''
+print '= second access on unfiltered, should not do call'
+print 'access', repo.testcachedfoobar
+print 'calllog:', calllog
+print 'cached value (unfiltered):',
+print vars(repo).get('testcachedfoobar', 'NOCACHE')
+
+print ''
+print '= first access on "visible" view, should do a call'
+visibleview = repo.filtered('visible')
+print 'cached value ("visible" view):',
+print vars(visibleview).get('testcachedfoobar', 'NOCACHE')
+print 'access:', visibleview.testcachedfoobar
+print 'calllog:', calllog
+print 'cached value (unfiltered):',
+print vars(repo).get('testcachedfoobar', 'NOCACHE')
+print 'cached value ("visible" view):',
+print vars(visibleview).get('testcachedfoobar', 'NOCACHE')
+
+print ''
+print '= second access on "visible view", should not do call'
+print 'access:', visibleview.testcachedfoobar
+print 'calllog:', calllog
+print 'cached value (unfiltered):',
+print vars(repo).get('testcachedfoobar', 'NOCACHE')
+print 'cached value ("visible" view):',
+print vars(visibleview).get('testcachedfoobar', 'NOCACHE')
+
+print ''
+print '= no effect on other view'
+immutableview = repo.filtered('immutable')
+print 'cached value ("immutable" view):',
+print vars(immutableview).get('testcachedfoobar', 'NOCACHE')
+print 'access:', immutableview.testcachedfoobar
+print 'calllog:', calllog
+print 'cached value (unfiltered):',
+print vars(repo).get('testcachedfoobar', 'NOCACHE')
+print 'cached value ("visible" view):',
+print vars(visibleview).get('testcachedfoobar', 'NOCACHE')
+print 'cached value ("immutable" view):',
+print vars(immutableview).get('testcachedfoobar', 'NOCACHE')
+
diff --git a/tests/test-propertycache.py.out b/tests/test-propertycache.py.out
new file mode 100644
--- /dev/null
+++ b/tests/test-propertycache.py.out
@@ -0,0 +1,36 @@
+
+=== property cache ===
+
+calllog: []
+cached value (unfiltered): NOCACHE
+
+= first access on unfiltered, should do a call
+access: 0
+calllog: [0]
+cached value (unfiltered): 0
+
+= second access on unfiltered, should not do call
+access 0
+calllog: [0]
+cached value (unfiltered): 0
+
+= first access on "visible" view, should do a call
+cached value ("visible" view): NOCACHE
+access: 7
+calllog: [0, 7]
+cached value (unfiltered): 0
+cached value ("visible" view): 7
+
+= second access on "visible view", should not do call
+access: 7
+calllog: [0, 7]
+cached value (unfiltered): 0
+cached value ("visible" view): 7
+
+= no effect on other view
+cached value ("immutable" view): NOCACHE
+access: 9
+calllog: [0, 7, 9]
+cached value (unfiltered): 0
+cached value ("visible" view): 7
+cached value ("immutable" view): 9