From fa5ee6ed2634b1a5b4388efb2c6ab6ae80356f28 Mon Sep 17 00:00:00 2001
From: Olivier Dony <odo@openerp.com>
Date: Sat, 11 Nov 2017 01:01:48 +0100
Subject: [PATCH] [FIX] ir_sequence: add support for PG 10

PostgreSQL 10 move sequences' metadata fields into a new `pg_sequence`
system catalog. As a result, selecting from a sequence relation now
only return three fields, and does not include the `increment_by`
metadata field anymore.

This patch obtains the `increment_by` value from the new system catalog
for PostgreSQL server versions >= 10.

Fixes #20269
---
 openerp/addons/base/ir/ir_sequence.py | 40 +++++++++++++++------------
 1 file changed, 22 insertions(+), 18 deletions(-)

diff --git a/openerp/addons/base/ir/ir_sequence.py b/openerp/addons/base/ir/ir_sequence.py
index 2a0f3ab47b7..25728399b19 100644
--- a/openerp/addons/base/ir/ir_sequence.py
+++ b/openerp/addons/base/ir/ir_sequence.py
@@ -63,6 +63,24 @@ def _update_nogap(self, number_increment):
     self.invalidate_cache(['number_next'], [self.id])
     return number_next
 
+def _predict_nextval(self, seq_id):
+    """Predict next value for PostgreSQL sequence without consuming it"""
+    # Cannot use currval() as it requires prior call to nextval()
+    query = """SELECT last_value,
+                      (SELECT increment_by
+                       FROM pg_sequences
+                       WHERE sequencename = 'ir_sequence_%(seq_id)s'),
+                      is_called
+               FROM ir_sequence_%(seq_id)s"""
+    if self.env.cr._cnx.server_version < 100000:
+        query = "SELECT last_value, increment_by, is_called FROM ir_sequence_%(seq_id)s"
+    self.env.cr.execute(query % {'seq_id': seq_id})
+    (last_value, increment_by, is_called) = self.env.cr.fetchone()
+    if is_called:
+        return last_value + increment_by
+    # sequence has just been RESTARTed to return last_value next time
+    return last_value
+
 
 class ir_sequence(models.Model):
     """ Sequence model.
@@ -82,15 +100,8 @@ class ir_sequence(models.Model):
             if element.implementation != 'standard':
                 element.number_next_actual = element.number_next
             else:
-                # get number from postgres sequence. Cannot use currval, because that might give an error when
-                # not having used nextval before.
-                query = "SELECT last_value, increment_by, is_called FROM ir_sequence_%03d" % element.id
-                self.env.cr.execute(query)
-                (last_value, increment_by, is_called) = self.env.cr.fetchone()
-                if is_called:
-                    element.number_next_actual = last_value + increment_by
-                else:
-                    element.number_next_actual = last_value
+                seq_id = "%03d" % element.id
+                element.number_next_actual = _predict_nextval(self, seq_id)
 
     def _set_number_next_actual(self):
         for record in self:
@@ -319,15 +330,8 @@ class ir_sequence_date_range(models.Model):
             if element.sequence_id.implementation != 'standard':
                 element.number_next_actual = element.number_next
             else:
-                # get number from postgres sequence. Cannot use currval, because that might give an error when
-                # not having used nextval before.
-                query = "SELECT last_value, increment_by, is_called FROM ir_sequence_%03d_%03d" % (element.sequence_id.id, element.id)
-                self.env.cr.execute(query)
-                (last_value, increment_by, is_called) = self.env.cr.fetchone()
-                if is_called:
-                    element.number_next_actual = last_value + increment_by
-                else:
-                    element.number_next_actual = last_value
+                seq_id = "%03d_%03d" % (element.sequence_id.id, element.id)
+                element.number_next_actual = _predict_nextval(self, seq_id)
 
     def _set_number_next_actual(self):
         for record in self: