[IMP] base: keep backward compatibility for decimal_precision

As the decimal_precision module was removed, allow code like

    from odoo.addons import decimal_precision as dp
    fields.Float(digits=dp.get_precision('Foo')

to keep working

Co-authored-by: Olivier Dony <odo@odoo.com>

odoo/addons/base/models/__init__.py

@@ -29,6 +29,7 @@ from . import ir_property
 from . import ir_module
 from . import ir_demo
 from . import ir_demo_failure
+
 from . import report_paperformat
 
 from . import image_mixin

odoo/addons/base/models/decimal_precision.py

@@ -2,6 +2,16 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
 from odoo import api, fields, models, tools
+import odoo.addons
+
+import logging
+import sys
+_logger = logging.getLogger(__name__)
+
+
+def get_precision(application):
+    _logger.warning("Deprecated call to decimal_precision.get_precision(<application>), use digits=<application> instead")
+    return application
 
 
 class DecimalPrecision(models.Model):
@@ -68,3 +78,10 @@ class DecimalPrecisionTestModel(models.Model):
     float = fields.Float()
     float_2 = fields.Float(digits=(16, 2))
     float_4 = fields.Float(digits=(16, 4))
+
+
+# compatibility for decimal_precision.get_precision(): expose the module in addons namespace
+dp = sys.modules['odoo.addons.base.models.decimal_precision']
+odoo.addons.decimal_precision = dp
+sys.modules['odoo.addons.decimal_precision'] = dp
+sys.modules['openerp.addons.decimal_precision'] = dp