1 files changed, 62 insertions, 2 deletions
diff --git a/lib/sqlalchemy/util/compat.py b/lib/sqlalchemy/util/compat.py
index 2d952c63f..bc0c3e6e0 100644
--- a/lib/sqlalchemy/util/compat.py
+++ b/lib/sqlalchemy/util/compat.py
@@ -17,6 +17,7 @@ except ImportError:
 
 py36 = sys.version_info >= (3, 6)
 py33 = sys.version_info >= (3, 3)
+py35 = sys.version_info >= (3, 5)
 py32 = sys.version_info >= (3, 2)
 py3k = sys.version_info >= (3, 0)
 py2k = sys.version_info < (3, 0)
@@ -166,6 +167,67 @@ else:
     itertools_imap = itertools.imap
     from itertools import izip_longest as zip_longest
 
+if py35:
+    from inspect import formatannotation
+
+    def inspect_formatargspec(
+            args, varargs=None, varkw=None, defaults=None,
+            kwonlyargs=(), kwonlydefaults={}, annotations={},
+            formatarg=str,
+            formatvarargs=lambda name: '*' + name,
+            formatvarkw=lambda name: '**' + name,
+            formatvalue=lambda value: '=' + repr(value),
+            formatreturns=lambda text: ' -> ' + text,
+            formatannotation=formatannotation):
+        """Copy formatargspec from python 3.7 standard library.
+
+        Python 3 has deprecated formatargspec and requested that Signature
+        be used instead, however this requires a full reimplementation
+        of formatargspec() in terms of creating Parameter objects and such.
+        Instead of introducing all the object-creation overhead and having
+        to reinvent from scratch, just copy their compatibility routine.
+
+        Utimately we would need to rewrite our "decorator" routine completely
+        which is not really worth it right now, until all Python 2.x support
+        is dropped.
+
+        """
+
+        def formatargandannotation(arg):
+            result = formatarg(arg)
+            if arg in annotations:
+                result += ': ' + formatannotation(annotations[arg])
+            return result
+        specs = []
+        if defaults:
+            firstdefault = len(args) - len(defaults)
+        for i, arg in enumerate(args):
+            spec = formatargandannotation(arg)
+            if defaults and i >= firstdefault:
+                spec = spec + formatvalue(defaults[i - firstdefault])
+            specs.append(spec)
+        if varargs is not None:
+            specs.append(formatvarargs(formatargandannotation(varargs)))
+        else:
+            if kwonlyargs:
+                specs.append('*')
+        if kwonlyargs:
+            for kwonlyarg in kwonlyargs:
+                spec = formatargandannotation(kwonlyarg)
+                if kwonlydefaults and kwonlyarg in kwonlydefaults:
+                    spec += formatvalue(kwonlydefaults[kwonlyarg])
+                specs.append(spec)
+        if varkw is not None:
+            specs.append(formatvarkw(formatargandannotation(varkw)))
+        result = '(' + ', '.join(specs) + ')'
+        if 'return' in annotations:
+            result += formatreturns(formatannotation(annotations['return']))
+        return result
+
+else:
+    from inspect import formatargspec as inspect_formatargspec
+
+
 
 import time
 if win32 or jython:
@@ -232,8 +294,6 @@ def with_metaclass(meta, *bases):
     return metaclass('temporary_class', None, {})
 
 
-
-
 @contextmanager
 def nested(*managers):
     """Implement contextlib.nested, mostly for unit tests.