base all_orm_descriptors ordering on cls.__dict__ + cls.__mro__

Adjusted the workings of the :meth:`_orm.Mapper.all_orm_descriptors`
accessor to represent the attributes in the order that they are located in
a deterministic way, assuming the use of Python 3.6 or higher which
maintains the sorting order of class attributes based on how they were
declared.   This sorting is not guaranteed to match the declared order of
attributes in all cases however; see the method documentation for the exact
scheme.

Fixes: #5494
Change-Id: I6ee8d4ace3eb8b3f7c9c0f2a3d7e27b5f62abfd3

diff --git a/doc/build/changelog/unreleased_13/5494.rst b/doc/build/changelog/unreleased_13/5494.rst
new file mode 100644 (file)
index 0000000..a9b594e
--- /dev/null
+++ b/doc/build/changelog/unreleased_13/5494.rst
@@ -0,0 +1,13 @@
+.. change::
+    :tags: usecase, orm
+    :tickets: 5494
+
+    Adjusted the workings of the :meth:`_orm.Mapper.all_orm_descriptors`
+    accessor to represent the attributes in the order that they are located in
+    a deterministic way, assuming the use of Python 3.6 or higher which
+    maintains the sorting order of class attributes based on how they were
+    declared.   This sorting is not guaranteed to match the declared order of
+    attributes in all cases however; see the method documentation for the exact
+    scheme.
+
+

diff --git a/lib/sqlalchemy/orm/instrumentation.py b/lib/sqlalchemy/orm/instrumentation.py
index 43e3801018a264dac09ed2e2ee4ab1bc9c879d0f..f647440831c6b9fb350cbfb5868278e1ad220c70 100644 (file)
--- a/lib/sqlalchemy/orm/instrumentation.py
+++ b/lib/sqlalchemy/orm/instrumentation.py
@@ -158,12 +158,24 @@ class ClassManager(HasMemoized, dict):
         :class:`.AssociationProxy`.
 
         """
-        if exclude is None:
-            exclude = set()
-        for supercls in self.class_.__mro__:
-            for key in set(supercls.__dict__).difference(exclude):
-                exclude.add(key)
-                val = supercls.__dict__[key]
+
+        found = {}
+
+        # constraints:
+        # 1. yield keys in cls.__dict__ order
+        # 2. if a subclass has the same key as a superclass, include that
+        #    key as part of the ordering of the superclass, because an
+        #    overridden key is usually installed by the mapper which is going
+        #    on a different ordering
+        # 3. don't use getattr() as this fires off descriptors
+
+        for supercls in self.class_.__mro__[0:-1]:
+            inherits = supercls.__mro__[1]
+            for key in supercls.__dict__:
+                found.setdefault(key, supercls)
+                if key in inherits.__dict__:
+                    continue
+                val = found[key].__dict__[key]
                 if (
                     isinstance(val, interfaces.InspectionAttr)
                     and val.is_attribute

diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py
index 6d22c620502d39ef51795d89d2c493adda3fdd0b..e428728e382d133b8cd898e05adfd02898336598 100644 (file)
--- a/lib/sqlalchemy/orm/mapper.py
+++ b/lib/sqlalchemy/orm/mapper.py
@@ -2434,6 +2434,21 @@ class Mapper(
         the attribute :attr:`.InspectionAttr.extension_type` will refer
         to a constant that distinguishes between different extension types.
 
+        The sorting of the attributes is based on what is located in
+        the ``__dict__`` of the mapped class as well as its mapped
+        superclasses.    The sorting will be all those attribute names
+        that appear in the ``__dict__`` of the immediate class and not
+        any of its superclasses, then the names which appear in the
+        ``__dict__`` of the superclass and not any of the further superclasses,
+        all the way down.   This will produce a deterministic ordering on
+        Python 3.6 and above.   It is not guaranteed to match the declared
+        ordering of attributes on the class, however, as the mapping process
+        itself populates Python descriptors into the ``__dict__`` of a mapped
+        class which are not always explicit in a declarative mapping.
+
+        .. versionchanged:: 1.4 ensured deterministic ordering for
+           :meth:`_orm.Mapper.all_orm_descriptors`.
+
         When dealing with a :class:`.QueryableAttribute`, the
         :attr:`.QueryableAttribute.property` attribute refers to the
         :class:`.MapperProperty` property, which is what you get when

diff --git a/lib/sqlalchemy/testing/requirements.py b/lib/sqlalchemy/testing/requirements.py
index 72f2612aac042ed973a6610c2bd5bf5c4128b3a6..25998c07bbea1c634ac0e155a282ceb00697e747 100644 (file)
--- a/lib/sqlalchemy/testing/requirements.py
+++ b/lib/sqlalchemy/testing/requirements.py
@@ -1104,6 +1104,10 @@ class SuiteRequirements(Requirements):
             lambda: sys.version_info < (3,), "Python version 3.xx is required."
         )
 
+    @property
+    def pep520(self):
+        return self.python36
+
     @property
     def python36(self):
         return exclusions.skip_if(

diff --git a/test/orm/test_inspect.py b/test/orm/test_inspect.py
index e99d46672840f72a754702b791dee2268b6520fe..7e15a09cebfa0f932ba9e16b554b9e65932f6381 100644 (file)
--- a/test/orm/test_inspect.py
+++ b/test/orm/test_inspect.py
@@ -434,6 +434,139 @@ class TestORMInspection(_fixtures.FixtureTest):
             set(["id", "name", "q", "foob"]),
         )
 
+    def _random_names(self):
+        import random
+
+        return [
+            "".join(
+                random.choice("abcdegfghijklmnopqrstuvwxyz")
+                for i in range(random.randint(3, 15))
+            )
+            for j in range(random.randint(4, 12))
+        ]
+
+    def _ordered_name_fixture(self, glbls, clsname, base, supercls):
+        import random
+        from sqlalchemy import Integer, Column
+        import textwrap
+
+        names = self._random_names()
+
+        if base is supercls:
+            pk_names = set(
+                random.choice(names) for i in range(random.randint(1, 3))
+            )
+            fk_name = random.choice(
+                [name for name in names if name not in pk_names]
+            )
+        else:
+            pk_names = []
+            fk_name = None
+
+        def _make_name(name):
+            if name in pk_names:
+                return "%s = Column(Integer, primary_key=True)" % name
+            elif name == fk_name:
+                return "%s = Column(ForeignKey('myotherclass.id'))" % name
+            else:
+                type_ = random.choice(["relationship", "column", "hybrid"])
+                if type_ == "relationship":
+                    return "%s = relationship('MyOtherClass')" % name
+                elif type_ == "column":
+                    return "%s = Column(Integer)" % name
+                elif type_ == "hybrid":
+                    return (
+                        "@hybrid_property\ndef %s(self):\n    return None"
+                        % name
+                    )
+
+        glbls["Base"] = base
+        glbls["SuperCls"] = supercls
+
+        if base is supercls:
+
+            class MyOtherClass(base):
+                __tablename__ = "myotherclass"
+                id = Column(Integer, primary_key=True)
+
+            glbls["MyOtherClass"] = MyOtherClass
+        code = """
+
+from sqlalchemy import Column, Integer, ForeignKey
+from sqlalchemy.orm import relationship
+from sqlalchemy.ext.hybrid import hybrid_property
+
+class %s(SuperCls):
+    %s
+
+%s
+""" % (
+            clsname,
+            "__tablename__ = 'mytable'" if base is supercls else "",
+            "\n".join(
+                textwrap.indent(_make_name(name), "    ") for name in names
+            ),
+        )
+
+        exec(code, glbls)
+        return names, glbls[clsname]
+
+    @testing.requires.pep520
+    def test_all_orm_descriptors_pep520_noinh(self):
+        from sqlalchemy.ext.declarative import declarative_base
+
+        Base = declarative_base()
+
+        glbls = {}
+        names, MyClass = self._ordered_name_fixture(
+            glbls, "MyClass", Base, Base
+        )
+
+        eq_(MyClass.__mapper__.all_orm_descriptors.keys(), names)
+
+    @testing.requires.pep520
+    def test_all_orm_descriptors_pep520_onelevel_inh(self):
+        from sqlalchemy.ext.declarative import declarative_base
+
+        Base = declarative_base()
+
+        glbls = {}
+
+        base_names, MyClass = self._ordered_name_fixture(
+            glbls, "MyClass", Base, Base
+        )
+
+        sub_names, SubClass = self._ordered_name_fixture(
+            glbls, "SubClass", Base, MyClass
+        )
+
+        eq_(
+            SubClass.__mapper__.all_orm_descriptors.keys(),
+            sub_names + base_names,
+        )
+
+    @testing.requires.pep520
+    def test_all_orm_descriptors_pep520_classical(self):
+        class MyClass(object):
+            pass
+
+        from sqlalchemy.orm import mapper
+        from sqlalchemy import Table, MetaData, Column, Integer
+
+        names = self._random_names()
+
+        m = MetaData()
+        t = Table(
+            "t",
+            m,
+            Column("id", Integer, primary_key=True),
+            *[Column(name, Integer) for name in names]
+        )
+
+        m = mapper(MyClass, t)
+
+        eq_(m.all_orm_descriptors.keys(), ["id"] + names)
+
     def test_instance_state_ident_transient(self):
         User = self.classes.User
         u1 = User(name="ed")