From 1cf5723835235c71df140938282420360116f0c5 Mon Sep 17 00:00:00 2001
From: Christophe Simonis <chs@odoo.com>
Date: Thu, 21 May 2015 12:53:56 +0200
Subject: [PATCH] Revert "Revert "[FIX] fields: `digits()` computation""

Thamks to parent commit, `request.env` doesn't raise `AttributeError`
anymore for requests without session bound to a database.

This exception was bubbling up to `digits` property (and `__getattr__`)

This reverts commit 49cb46fb78de4e7e88b054f2b5df21612778fd40.
This reinstate commit eeedd2d9f52d46d8193059854e7430ca0c1fd6c0.
---
 openerp/fields.py     |  3 ++-
 openerp/osv/fields.py | 24 ++++++++++++++++++------
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/openerp/fields.py b/openerp/fields.py
index d780bf5adb3..cd25295d8e6 100644
--- a/openerp/fields.py
+++ b/openerp/fields.py
@@ -1054,7 +1054,8 @@ class Float(Field):
     @property
     def digits(self):
         if callable(self._digits):
-            return self._digits(fields.get_cursor())
+            with fields._get_cursor() as cr:
+                return self._digits(cr)
         else:
             return self._digits
 
diff --git a/openerp/osv/fields.py b/openerp/osv/fields.py
index 02d24fdf47b..00eba168552 100644
--- a/openerp/osv/fields.py
+++ b/openerp/osv/fields.py
@@ -43,6 +43,7 @@ import pytz
 import re
 import xmlrpclib
 from operator import itemgetter
+from contextlib import contextmanager
 from psycopg2 import Binary
 
 import openerp
@@ -52,13 +53,22 @@ from openerp.tools import float_repr, float_round, frozendict, html_sanitize
 import simplejson
 from openerp import SUPERUSER_ID, registry
 
-def get_cursor():
-    # retrieve a valid cursor from any environment
+@contextmanager
+def _get_cursor():
+    # yield a valid cursor from any environment or create a new one if none found
     from openerp.api import Environment
+    from openerp.http import request
+    try:
+        request.env     # force request's env to be computed
+    except RuntimeError:
+        pass    # ignore if not in a request
     for env in Environment.envs:
         if not env.cr.closed:
-            return env.cr
-    raise RuntimeError("No valid cursor found")
+            yield env.cr
+            break
+    else:
+        with registry().cursor() as cr:
+            yield cr
 
 EMPTY_DICT = frozendict()
 
@@ -396,7 +406,8 @@ class float(_column):
     @property
     def digits(self):
         if self._digits_compute:
-            return self._digits_compute(get_cursor())
+            with _get_cursor() as cr:
+                return self._digits_compute(cr)
         else:
             return self._digits
 
@@ -1316,7 +1327,8 @@ class function(_column):
     @property
     def digits(self):
         if self._digits_compute:
-            return self._digits_compute(get_cursor())
+            with _get_cursor() as cr:
+                return self._digits_compute(cr)
         else:
             return self._digits