Unify Query and select() , move all processing to compile phase

Convert Query to do virtually all compile state computation
in the _compile_context() phase, and organize it all
such that a plain select() construct may also be used as the
source of information in order to generate ORM query state.
This makes it such that Query is not needed except for
its additional methods like from_self() which are all to
be deprecated.

The construction of ORM state will occur beyond the
caching boundary when the new execution model is integrated.

future select() gains a working join() and filter_by() method.
as we continue to rebase and merge each commit in the steps,
callcounts continue to bump around.  will have to look at
the final result when it's all in.

References: #5159
References: #4705
References: #4639
References: #4871
References: #5010

Change-Id: I19e05b3424b07114cce6c439b05198ac47f7ac10

1 files changed, 10 insertions, 0 deletions

diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index ccc1b53fe..9a7646743 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -653,6 +653,12 @@ class SQLCompiler(Compiled):
 
     """
 
+    compile_state_factories = util.immutabledict()
+    """Dictionary of alternate :class:`.CompileState` factories for given
+    classes, identified by their visit_name.
+
+    """
+
     def __init__(
         self,
         dialect,
@@ -661,6 +667,7 @@ class SQLCompiler(Compiled):
         column_keys=None,
         inline=False,
         linting=NO_LINTING,
+        compile_state_factories=None,
         **kwargs
     ):
         """Construct a new :class:`.SQLCompiler` object.
@@ -727,6 +734,9 @@ class SQLCompiler(Compiled):
         # dialect.label_length or dialect.max_identifier_length
         self.truncated_names = {}
 
+        if compile_state_factories:
+            self.compile_state_factories = compile_state_factories
+
         Compiled.__init__(self, dialect, statement, **kwargs)
 
         if (