Rename Table.tometadata to to_metadata

Renamed the :meth:`_schema.Table.tometadata` method to
:meth:`_schema.Table.to_metadata`.  The previous name remains with a
deprecation warning.

Updated the "decorate" utility function to support decoration
of functions that include non-builtins as default values.

Moves test for deprecated "databases" package into
test/dialect/test_deprecations.py

Fixes: #5413
Fixes: #5426
Change-Id: I6ed899871c935f9e46360127c17ccb7cf97cea6e

1 files changed, 28 insertions, 3 deletions

diff --git a/lib/sqlalchemy/util/langhelpers.py b/lib/sqlalchemy/util/langhelpers.py
index 52debc517..57d3be83b 100644
--- a/lib/sqlalchemy/util/langhelpers.py
+++ b/lib/sqlalchemy/util/langhelpers.py
@@ -144,6 +144,10 @@ def decorator(target):
             raise Exception("not a decoratable function")
 
         spec = compat.inspect_getfullargspec(fn)
+        env = {}
+
+        spec = _update_argspec_defaults_into_env(spec, env)
+
         names = tuple(spec[0]) + spec[1:3] + (fn.__name__,)
         targ_name, fn_name = _unique_symbols(names, "target", "fn")
 
@@ -157,9 +161,9 @@ def %(name)s(%(args)s):
 """
             % metadata
         )
-        decorated = _exec_code_in_env(
-            code, {targ_name: target, fn_name: fn}, fn.__name__
-        )
+        env.update({targ_name: target, fn_name: fn})
+
+        decorated = _exec_code_in_env(code, env, fn.__name__)
         decorated.__defaults__ = getattr(fn, "im_func", fn).__defaults__
         decorated.__wrapped__ = fn
         return update_wrapper(decorated, fn)
@@ -167,6 +171,27 @@ def %(name)s(%(args)s):
     return update_wrapper(decorate, target)
 
 
+def _update_argspec_defaults_into_env(spec, env):
+    """given a FullArgSpec, convert defaults to be symbol names in an env."""
+
+    if spec.defaults:
+        new_defaults = []
+        i = 0
+        for arg in spec.defaults:
+            if type(arg).__module__ not in ("builtins", "__builtin__"):
+                name = "x%d" % i
+                env[name] = arg
+                new_defaults.append(name)
+                i += 1
+            else:
+                new_defaults.append(arg)
+        elem = list(spec)
+        elem[3] = tuple(new_defaults)
+        return compat.FullArgSpec(*elem)
+    else:
+        return spec
+
+
 def _exec_code_in_env(code, env, fn_name):
     exec(code, env)
     return env[fn_name]