From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Fri, 20 Nov 2020 15:12:18 +0000 (-0500)
Subject: Don't emit warnings on descriptor access
X-Git-Tag: rel_1_4_0b2~139^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3241e3ca728c883adb4f8e859c77168c3361d957;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

Don't emit warnings on descriptor access

This commit is revising 5162f2bc5fc0ac239f26a76fc9f0c2, which
when I did it felt a little rushed but I couldn't find anything
wrong.  Well here we are :).

Fixed issue where a :class:`.RemovedIn20Warning` would erroneously emit
when the ``.bind`` attribute were accessed internally on objects,
particularly when stringifying a SQL construct.

Alter the deprecated() decorator so that we can use it just to add
docstring warnings but not actually warn when the function is
accessed, adding new argument enable_warnings that can be
set to False.

Added a safety feature to deprecated_20() that will disallow an
":attr:" from proceeding if enable_warnings=False isn't present,
unless there's an extra flag
warn_on_attribute_access, since we want Session.transaction to
emit a deprecation warning.  This is a little hacky but it's essentially
modifying the decorator to require a positive assertion that
a deprecation decorator on a descriptor should actually warn
on access.

Remove the warning filter for session.transaction and get
tests to pass to ensure this is not also being called
internally.

Added tests to ensure that common places .bind can be passed
as a parameter definitely warn as I was not able to find
this otherwise.

Fixes: #5717
Change-Id: Ia586b4f9ee6b212f3a71104b1caf40b5edd399e2
---

diff --git a/doc/build/changelog/unreleased_14/5717.rst b/doc/build/changelog/unreleased_14/5717.rst
new file mode 100644
index 0000000000..af8c716c03
--- /dev/null
+++ b/doc/build/changelog/unreleased_14/5717.rst
@@ -0,0 +1,7 @@
+.. change::
+    :tags: bug, sql
+    :tickets: 5717
+
+    Fixed issue where a :class:`.RemovedIn20Warning` would erroneously emit
+    when the ``.bind`` attribute were accessed internally on objects,
+    particularly when stringifying a SQL construct.
diff --git a/lib/sqlalchemy/orm/session.py b/lib/sqlalchemy/orm/session.py
index 2fc2ad68c6..b89edca446 100644
--- a/lib/sqlalchemy/orm/session.py
+++ b/lib/sqlalchemy/orm/session.py
@@ -1053,6 +1053,7 @@ class Session(_SessionClassMethods):
         ":meth:`_orm.Session.begin`.  To access "
         "the current root transaction, use "
         ":meth:`_orm.Session.get_transaction`.",
+        warn_on_attribute_access=True,
     )
     def transaction(self):
         """The current active or inactive :class:`.SessionTransaction`.
@@ -1065,6 +1066,9 @@ class Session(_SessionClassMethods):
 
 
         """
+        return self._legacy_transaction()
+
+    def _legacy_transaction(self):
         if not self.future:
             self._autobegin()
         return self._transaction
diff --git a/lib/sqlalchemy/sql/base.py b/lib/sqlalchemy/sql/base.py
index 999169f90c..ff44ab27c9 100644
--- a/lib/sqlalchemy/sql/base.py
+++ b/lib/sqlalchemy/sql/base.py
@@ -909,6 +909,7 @@ class Executable(Generative):
     @util.deprecated_20(
         ":attr:`.Executable.bind`",
         alternative="Bound metadata is being removed as of SQLAlchemy 2.0.",
+        enable_warnings=False,
     )
     def bind(self):
         """Returns the :class:`_engine.Engine` or :class:`_engine.Connection`
diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py
index 086cef48a9..d60afdbacf 100644
--- a/lib/sqlalchemy/sql/selectable.py
+++ b/lib/sqlalchemy/sql/selectable.py
@@ -1238,6 +1238,7 @@ class Join(roles.DMLTableRole, FromClause):
     @util.deprecated_20(
         ":attr:`.Executable.bind`",
         alternative="Bound metadata is being removed as of SQLAlchemy 2.0.",
+        enable_warnings=False,
     )
     def bind(self):
         """Return the bound engine associated with either the left or right
@@ -3559,6 +3560,7 @@ class CompoundSelect(HasCompileState, GenerativeSelect):
     @util.deprecated_20(
         ":attr:`.Executable.bind`",
         alternative="Bound metadata is being removed as of SQLAlchemy 2.0.",
+        enable_warnings=False,
     )
     def bind(self):
         """Returns the :class:`_engine.Engine` or :class:`_engine.Connection`
@@ -5443,6 +5445,7 @@ class Select(
     @util.deprecated_20(
         ":attr:`.Executable.bind`",
         alternative="Bound metadata is being removed as of SQLAlchemy 2.0.",
+        enable_warnings=False,
     )
     def bind(self):
         """Returns the :class:`_engine.Engine` or :class:`_engine.Connection`
diff --git a/lib/sqlalchemy/testing/warnings.py b/lib/sqlalchemy/testing/warnings.py
index 2a0be42c1f..b230bad6f0 100644
--- a/lib/sqlalchemy/testing/warnings.py
+++ b/lib/sqlalchemy/testing/warnings.py
@@ -63,7 +63,6 @@ def setup_filters():
         #
         r"The MetaData.bind argument is deprecated",
         r"The ``bind`` argument for schema methods that invoke SQL ",
-        r"The Executable.bind attribute is considered legacy ",
         r"The Function.bind argument",
         r"The select.bind argument",
         #
@@ -131,7 +130,6 @@ def setup_filters():
         r".*object is being merged into a Session along the backref "
         "cascade path",
         r"Passing bind arguments to Session.execute\(\) as keyword arguments",
-        r"The Session.transaction attribute",
         r"The merge_result\(\) method is superseded by the "
         r"merge_frozen_result\(\)",
         r"The Session.begin.subtransactions flag is deprecated",
diff --git a/lib/sqlalchemy/util/deprecations.py b/lib/sqlalchemy/util/deprecations.py
index f463746012..a4c9d9d0e9 100644
--- a/lib/sqlalchemy/util/deprecations.py
+++ b/lib/sqlalchemy/util/deprecations.py
@@ -112,7 +112,11 @@ def deprecated_20_cls(
 
 
 def deprecated(
-    version, message=None, add_deprecation_to_docstring=True, warning=None
+    version,
+    message=None,
+    add_deprecation_to_docstring=True,
+    warning=None,
+    enable_warnings=True,
 ):
     """Decorates a function and issues a deprecation warning on use.
 
@@ -157,7 +161,12 @@ def deprecated(
 
     def decorate(fn):
         return _decorate_with_warning(
-            fn, warning, message % dict(func=fn.__name__), version, header
+            fn,
+            warning,
+            message % dict(func=fn.__name__),
+            version,
+            header,
+            enable_warnings=enable_warnings,
         )
 
     return decorate
@@ -189,6 +198,16 @@ def deprecated_20(api_name, alternative=None, becomes_legacy=False, **kw):
         )
     )
 
+    if ":attr:" in api_name:
+        attribute_ok = kw.pop("warn_on_attribute_access", False)
+        if not attribute_ok:
+            assert kw.get("enable_warnings") is False, (
+                "attribute %s will emit a warning on read access.  "
+                "If you *really* want this, "
+                "add warn_on_attribute_access=True.  Otherwise please add "
+                "enable_warnings=False." % api_name
+            )
+
     if alternative:
         message += " " + alternative
 
@@ -347,7 +366,7 @@ def _decorate_cls_with_warning(
 
 
 def _decorate_with_warning(
-    func, wtype, message, version, docstring_header=None
+    func, wtype, message, version, docstring_header=None, enable_warnings=True
 ):
     """Wrap a function with a warnings.warn and augmented docstring."""
 
@@ -363,7 +382,9 @@ def _decorate_with_warning(
 
     @decorator
     def warned(fn, *args, **kwargs):
-        skip_warning = kwargs.pop("_sa_skip_warning", False)
+        skip_warning = not enable_warnings or kwargs.pop(
+            "_sa_skip_warning", False
+        )
         if not skip_warning:
             _warn_with_version(message, version, wtype, stacklevel=3)
         return fn(*args, **kwargs)
diff --git a/test/aaa_profiling/test_orm.py b/test/aaa_profiling/test_orm.py
index 1bbfd36586..f87f610745 100644
--- a/test/aaa_profiling/test_orm.py
+++ b/test/aaa_profiling/test_orm.py
@@ -108,7 +108,7 @@ class MergeTest(NoCache, fixtures.MappedTest):
         # down from 185 on this this is a small slice of a usually
         # bigger operation so using a small variance
 
-        sess2.transaction  # autobegin
+        sess2._legacy_transaction()  # autobegin
 
         @profiling.function_call_count(variance=0.20)
         def go1():
@@ -118,7 +118,7 @@ class MergeTest(NoCache, fixtures.MappedTest):
 
         # third call, merge object already present. almost no calls.
 
-        sess2.transaction  # autobegin
+        sess2._legacy_transaction()  # autobegin
 
         @profiling.function_call_count(variance=0.10, warmup=1)
         def go2():
@@ -138,7 +138,7 @@ class MergeTest(NoCache, fixtures.MappedTest):
         # using sqlite3 the C extension took it back up to approx. 1257
         # (py2.6)
 
-        sess2.transaction  # autobegin
+        sess2._legacy_transaction()  # autobegin
 
         @profiling.function_call_count(variance=0.10)
         def go():
diff --git a/test/orm/test_bind.py b/test/orm/test_bind.py
index fef827d833..3a99598570 100644
--- a/test/orm/test_bind.py
+++ b/test/orm/test_bind.py
@@ -405,7 +405,7 @@ class BindIntegrationTest(_fixtures.FixtureTest):
         c = testing.db.connect()
         sess = create_session(bind=c)
         sess.begin()
-        transaction = sess.transaction
+        transaction = sess._legacy_transaction()
         u = User(name="u1")
         sess.add(u)
         sess.flush()
diff --git a/test/orm/test_deprecations.py b/test/orm/test_deprecations.py
index 47e8041132..4bd921af45 100644
--- a/test/orm/test_deprecations.py
+++ b/test/orm/test_deprecations.py
@@ -1994,6 +1994,19 @@ class SubqRelationsFromSelfTest(fixtures.DeclarativeMappedTest):
 
 
 class SessionTest(fixtures.RemovesEvents, _LocalFixture):
+    def test_transaction_attr(self):
+        s1 = Session(testing.db)
+
+        with testing.expect_deprecated_20(
+            "The Session.transaction attribute is considered legacy as "
+            "of the 1.x series"
+        ):
+            s1.transaction
+
+    def test_session_str(self):
+        s1 = Session(testing.db)
+        str(s1)
+
     def test_subtransactions_deprecated(self):
         s1 = Session(testing.db)
         s1.begin()
diff --git a/test/orm/test_session.py b/test/orm/test_session.py
index 4562df44a6..1650082346 100644
--- a/test/orm/test_session.py
+++ b/test/orm/test_session.py
@@ -501,7 +501,7 @@ class SessionStateTest(_fixtures.FixtureTest):
         sess.flush()
         assert u1 not in sess
         assert_raises(sa.exc.InvalidRequestError, sess.add, u1)
-        assert sess.transaction is not None
+        assert sess.in_transaction()
         sess.rollback()
         assert u1 in sess
 
diff --git a/test/orm/test_transaction.py b/test/orm/test_transaction.py
index 497693de28..e8f6c5c405 100644
--- a/test/orm/test_transaction.py
+++ b/test/orm/test_transaction.py
@@ -48,7 +48,7 @@ class SessionTransactionTest(fixtures.RemovesEvents, FixtureTest):
             mapper(User, users)
             s = create_session(bind=c)
             s.begin()
-            tran = s.transaction
+            tran = s._legacy_transaction()
             s.add(User(name="first"))
             s.flush()
             c.exec_driver_sql("select * from users")
@@ -58,7 +58,7 @@ class SessionTransactionTest(fixtures.RemovesEvents, FixtureTest):
             u = User(name="third")
             s.add(u)
             s.flush()
-            assert s.transaction is tran
+            assert s._legacy_transaction() is tran
             tran.close()
         finally:
             c.close()
@@ -564,7 +564,7 @@ class SessionTransactionTest(fixtures.RemovesEvents, FixtureTest):
         sess.add(User(name="u2"))
 
         t2.commit()
-        assert sess.transaction is t1
+        assert sess._legacy_transaction() is t1
 
         sess.close()
 
@@ -1024,9 +1024,9 @@ class SessionTransactionTest(fixtures.RemovesEvents, FixtureTest):
         mapper(User, users)
         session = create_session(autocommit=False)
         session.add(User(name="ed"))
-        session.transaction.commit()
+        session._legacy_transaction().commit()
 
-        is_not(session.transaction, None)
+        is_not(session._legacy_transaction(), None)
 
     def test_no_autocommit_with_explicit_commit_future(self):
         User, users = self.classes.User, self.tables.users
@@ -1034,10 +1034,10 @@ class SessionTransactionTest(fixtures.RemovesEvents, FixtureTest):
         mapper(User, users)
         session = create_session(testing.db, autocommit=False, future=True)
         session.add(User(name="ed"))
-        session.transaction.commit()
+        session._legacy_transaction().commit()
 
         # new in 1.4
-        is_(session.transaction, None)
+        is_(session._legacy_transaction(), None)
 
     @testing.requires.python2
     @testing.requires.savepoints_w_release
@@ -1278,7 +1278,7 @@ class SubtransactionRecipeTest(FixtureTest):
         sess.add(User(name="u2"))
 
         t2.commit()
-        assert sess.transaction is t1
+        assert sess._legacy_transaction() is t1
 
         sess.close()
 
@@ -1317,7 +1317,7 @@ class SubtransactionRecipeTest(FixtureTest):
 
             try:
                 with subtransaction_recipe(sess):
-                    assert sess.transaction
+                    assert sess._legacy_transaction()
                     raise Exception("force rollback")
             except:
                 pass
@@ -1921,7 +1921,7 @@ class SavepointTest(_LocalFixture):
         nested_trans = trans._connections[self.bind][1]
         nested_trans._do_commit()
 
-        is_(s.transaction, trans)
+        is_(s._legacy_transaction(), trans)
 
         with expect_warnings("nested transaction already deassociated"):
             # this previously would raise
@@ -1932,12 +1932,12 @@ class SavepointTest(_LocalFixture):
         assert u1 not in s.new
 
         is_(trans._state, _session.CLOSED)
-        is_not(s.transaction, trans)
-        is_(s.transaction._state, _session.ACTIVE)
+        is_not(s._legacy_transaction(), trans)
+        is_(s._legacy_transaction()._state, _session.ACTIVE)
 
-        is_(s.transaction.nested, False)
+        is_(s._legacy_transaction().nested, False)
 
-        is_(s.transaction._parent, None)
+        is_(s._legacy_transaction()._parent, None)
 
 
 class AccountingFlagsTest(_LocalFixture):
@@ -2118,7 +2118,7 @@ class ContextManagerPlusFutureTest(FixtureTest):
     def test_explicit_begin(self):
         s1 = Session(testing.db)
         with s1.begin() as trans:
-            is_(trans, s1.transaction)
+            is_(trans, s1._legacy_transaction())
             s1.connection()
 
         is_(s1._transaction, None)
@@ -2152,12 +2152,12 @@ class ContextManagerPlusFutureTest(FixtureTest):
 
         # rolls back the whole transaction
         s1.rollback()
-        is_(s1.transaction, None)
+        is_(s1._legacy_transaction(), None)
 
         eq_(s1.connection().scalar(select(func.count()).select_from(users)), 0)
 
         s1.commit()
-        is_(s1.transaction, None)
+        is_(s1._legacy_transaction(), None)
 
     @testing.requires.savepoints
     def test_old_rollback_is_local(self):
@@ -2180,19 +2180,19 @@ class ContextManagerPlusFutureTest(FixtureTest):
         # rolls back only the savepoint
         s1.rollback()
 
-        is_(s1.transaction, t1)
+        is_(s1._legacy_transaction(), t1)
 
         eq_(s1.connection().scalar(select(func.count()).select_from(users)), 1)
 
         s1.commit()
         eq_(s1.connection().scalar(select(func.count()).select_from(users)), 1)
-        is_not(s1.transaction, None)
+        is_not(s1._legacy_transaction(), None)
 
     def test_session_as_ctx_manager_one(self):
         users = self.tables.users
 
         with Session(testing.db) as sess:
-            is_not(sess.transaction, None)
+            is_not(sess._legacy_transaction(), None)
 
             sess.connection().execute(
                 users.insert().values(id=1, name="user1")
@@ -2202,9 +2202,9 @@ class ContextManagerPlusFutureTest(FixtureTest):
                 sess.connection().execute(users.select()).all(), [(1, "user1")]
             )
 
-            is_not(sess.transaction, None)
+            is_not(sess._legacy_transaction(), None)
 
-        is_not(sess.transaction, None)
+        is_not(sess._legacy_transaction(), None)
 
         # did not commit
         eq_(sess.connection().execute(users.select()).all(), [])
@@ -2213,7 +2213,7 @@ class ContextManagerPlusFutureTest(FixtureTest):
         users = self.tables.users
 
         with Session(testing.db, future=True) as sess:
-            is_(sess.transaction, None)
+            is_(sess._legacy_transaction(), None)
 
             sess.connection().execute(
                 users.insert().values(id=1, name="user1")
@@ -2223,9 +2223,9 @@ class ContextManagerPlusFutureTest(FixtureTest):
                 sess.connection().execute(users.select()).all(), [(1, "user1")]
             )
 
-            is_not(sess.transaction, None)
+            is_not(sess._legacy_transaction(), None)
 
-        is_(sess.transaction, None)
+        is_(sess._legacy_transaction(), None)
 
         # did not commit
         eq_(sess.connection().execute(users.select()).all(), [])
@@ -2235,7 +2235,7 @@ class ContextManagerPlusFutureTest(FixtureTest):
 
         try:
             with Session(testing.db) as sess:
-                is_not(sess.transaction, None)
+                is_not(sess._legacy_transaction(), None)
 
                 sess.connection().execute(
                     users.insert().values(id=1, name="user1")
@@ -2244,14 +2244,14 @@ class ContextManagerPlusFutureTest(FixtureTest):
                 raise Exception("force rollback")
         except:
             pass
-        is_not(sess.transaction, None)
+        is_not(sess._legacy_transaction(), None)
 
     def test_session_as_ctx_manager_two_future(self):
         users = self.tables.users
 
         try:
             with Session(testing.db, future=True) as sess:
-                is_(sess.transaction, None)
+                is_(sess._legacy_transaction(), None)
 
                 sess.connection().execute(
                     users.insert().values(id=1, name="user1")
@@ -2260,7 +2260,7 @@ class ContextManagerPlusFutureTest(FixtureTest):
                 raise Exception("force rollback")
         except:
             pass
-        is_(sess.transaction, None)
+        is_(sess._legacy_transaction(), None)
 
     def test_begin_context_manager(self):
         users = self.tables.users
diff --git a/test/orm/test_unitofwork.py b/test/orm/test_unitofwork.py
index dcd9219a43..eb5530ef42 100644
--- a/test/orm/test_unitofwork.py
+++ b/test/orm/test_unitofwork.py
@@ -3307,7 +3307,7 @@ class TransactionTest(fixtures.MappedTest):
             assert False
         except Exception:
             # Flush needs to rollback also when commit fails
-            assert session.transaction is None
+            assert session._legacy_transaction() is None
 
         # todo: on 8.3 at least, the failed commit seems to close the cursor?
         # needs investigation.  leaving in the DDL above now to help verify
diff --git a/test/sql/test_deprecations.py b/test/sql/test_deprecations.py
index 5f86b0b89f..c0d2e87e86 100644
--- a/test/sql/test_deprecations.py
+++ b/test/sql/test_deprecations.py
@@ -90,6 +90,48 @@ class BoundMetadataTest(fixtures.TestBase):
 
         assert "t" not in inspect(testing.db).get_table_names()
 
+    def test_bind_arg_text(self):
+        with testing.expect_deprecated_20(
+            "The text.bind argument is deprecated and will be "
+            "removed in SQLAlchemy 2.0."
+        ):
+            t1 = text("ASdf", bind=testing.db)
+
+        # no warnings emitted
+        is_(t1.bind, testing.db)
+        eq_(str(t1), "ASdf")
+
+    def test_bind_arg_function(self):
+        with testing.expect_deprecated_20(
+            "The text.bind argument is deprecated and will be "
+            "removed in SQLAlchemy 2.0."
+        ):
+            f1 = func.foobar(bind=testing.db)
+
+        # no warnings emitted
+        is_(f1.bind, testing.db)
+        eq_(str(f1), "foobar()")
+
+    def test_bind_arg_select(self):
+        with testing.expect_deprecated_20(
+            "The select.bind argument is deprecated and will be "
+            "removed in SQLAlchemy 2.0."
+        ):
+            s1 = select([column("q")], bind=testing.db)
+
+        # no warnings emitted
+        is_(s1.bind, testing.db)
+        eq_(str(s1), "SELECT q")
+
+    def test_bind_attr_join_no_warning(self):
+        t1 = table("t1", column("a"))
+        t2 = table("t2", column("b"))
+        j1 = join(t1, t2, t1.c.a == t2.c.b)
+
+        # no warnings emitted
+        is_(j1.bind, None)
+        eq_(str(j1), "t1 JOIN t2 ON t1.a = t2.b")
+
 
 class DeprecationWarningsTest(fixtures.TestBase, AssertsCompiledSQL):
     __backend__ = True