[ADD] misc.Sentinel

Light object to represent a sentinel (surprising, isn't it?) that render
well in function's help() output.

closes #238

Signed-off-by: Christophe Simonis (chs) <chs@odoo.com>

Author: KangOl

src/util/convert_bootstrap.py

@@ -8,6 +8,7 @@
 
 from lxml import etree
 
+from .misc import Sentinel
 from .misc import parse_version as Version
 
 _logger = logging.getLogger(__name__)
@@ -228,7 +229,7 @@ def edit_element_classes(element, add, remove, is_qweb=False):
         edit_element_t_classes(element, add, remove)
 
 
-ALL = object()
+ALL = Sentinel("ALL")
 """Sentinel object to indicate "all items" in a collection"""
 
 

src/util/inconsistencies.py

@@ -8,7 +8,7 @@
 from psycopg2.sql import SQL
 
 from .helpers import _validate_model, table_of_model
-from .misc import chunks, str2bool
+from .misc import Sentinel, chunks, str2bool
 from .pg import format_query, get_value_or_en_translation, target_of
 from .report import add_to_migration_reports, get_anchor_link_to_record, html_escape
 
@@ -20,7 +20,7 @@
 )
 FIX_PRODUCT_UOM = str2bool(os.environ.get("ODOO_MIG_FIX_ALL_UOM_INCONSISTENCIES"), default=False)
 
-FROM_ENV = object()
+FROM_ENV = Sentinel("FROM_ENV")
 
 
 def break_recursive_loops(cr, model, field, name_field="name"):

src/util/misc.py

@@ -39,8 +39,19 @@
 _logger = logging.getLogger(__name__)
 
 
+class Sentinel:
+    # waiting PEP661...
+    __slots__ = ("name",)
+
+    def __init__(self, name):
+        self.name = name
+
+    def __repr__(self):
+        return self.name
+
+
 def _cached(func):
-    sentinel = object()
+    sentinel = Sentinel("sentinel")
 
     @functools.wraps(func)
     def wrapper(*args, **kwargs):

src/util/pg.py

@@ -43,7 +43,7 @@
 
 from .exceptions import MigrationError, SleepyDeveloperError
 from .helpers import _validate_table, model_of_table
-from .misc import log_progress
+from .misc import Sentinel, log_progress
 
 _logger = logging.getLogger(__name__)
 
@@ -541,7 +541,7 @@ def create_column(cr, table, column, definition, **kwargs):
     :rtype: bool
     """
     # Manual PEP 3102
-    no_def = object()
+    no_def = Sentinel("no_def")
     default = kwargs.pop("default", no_def)
     fk_table = kwargs.pop("fk_table", no_def)
     on_delete_action = kwargs.pop("on_delete_action", no_def)
@@ -961,7 +961,7 @@ def get_depending_views(cr, table, column):
 
 
 # sentinel object for function parameters to not alter.
-KEEP_CURRENT = object()
+KEEP_CURRENT = Sentinel("KEEP_CURRENT")
 
 
 class ColumnList(UserList, sql.Composable):