Fixes for public_factory and mysql/pg dml functions

* ensure that the location indicated by public_factory is
  importable

* adjust all of sqlalchemy.sql.expression locations to be correct

* support the case where a public_factory is against a function
  that has another public_factory already, and already replaced the
  __init__ on the target class

* Use mysql.insert(), postgresql.insert(), don't include .dml in the
  class path.

Change-Id: Iac285289455d8d7102349df3814f7cedc758e639

2 files changed, 12 insertions, 7 deletions

diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py
index 82c619c85..ceefc20b0 100644
--- a/lib/sqlalchemy/dialects/postgresql/base.py
+++ b/lib/sqlalchemy/dialects/postgresql/base.py
@@ -304,9 +304,9 @@ or they may be *inferred* by stating the columns and conditions that comprise
 the indexes.
 
 SQLAlchemy provides ``ON CONFLICT`` support via the PostgreSQL-specific
-:func:`.postgresql.dml.insert()` function, which provides
-the generative methods :meth:`~.postgresql.dml.Insert.on_conflict_do_update`
-and :meth:`~.postgresql.dml.Insert.on_conflict_do_nothing`::
+:func:`.postgresql.insert()` function, which provides
+the generative methods :meth:`~.postgresql.Insert.on_conflict_do_update`
+and :meth:`~.postgresql.Insert.on_conflict_do_nothing`::
 
     from sqlalchemy.dialects.postgresql import insert
 
@@ -415,8 +415,8 @@ for UPDATE::
     :paramref:`.Insert.on_conflict_do_update.set_` dictionary.
 
 In order to refer to the proposed insertion row, the special alias
-:attr:`~.postgresql.dml.Insert.excluded` is available as an attribute on
-the :class:`.postgresql.dml.Insert` object; this object is a
+:attr:`~.postgresql.Insert.excluded` is available as an attribute on
+the :class:`.postgresql.Insert` object; this object is a
 :class:`.ColumnCollection` which alias contains all columns of the target
 table::
 
@@ -452,7 +452,7 @@ parameter, which will limit those rows which receive an UPDATE::
 ``ON CONFLICT`` may also be used to skip inserting a row entirely
 if any conflict with a unique or exclusion constraint occurs; below
 this is illustrated using the
-:meth:`~.postgresql.dml.Insert.on_conflict_do_nothing` method::
+:meth:`~.postgresql.Insert.on_conflict_do_nothing` method::
 
     from sqlalchemy.dialects.postgresql import insert
 
diff --git a/lib/sqlalchemy/dialects/postgresql/dml.py b/lib/sqlalchemy/dialects/postgresql/dml.py
index ec40ae87e..626f81018 100644
--- a/lib/sqlalchemy/dialects/postgresql/dml.py
+++ b/lib/sqlalchemy/dialects/postgresql/dml.py
@@ -23,6 +23,9 @@ class Insert(StandardInsert):
 
     Adds methods for PG-specific syntaxes such as ON CONFLICT.
 
+    The :class:`.postgresql.Insert` object is created using the
+    :func:`sqlalchemy.dialects.postgresql.insert` function.
+
     .. versionadded:: 1.1
 
     """
@@ -139,7 +142,9 @@ class Insert(StandardInsert):
         )
 
 
-insert = public_factory(Insert, ".dialects.postgresql.insert")
+insert = public_factory(
+    Insert, ".dialects.postgresql.insert", ".dialects.postgresql.Insert"
+)
 
 
 class OnConflictClause(ClauseElement):