1 files changed, 112 insertions, 0 deletions
diff --git a/lib/sqlalchemy/util/deprecations.py b/lib/sqlalchemy/util/deprecations.py
new file mode 100644
index 000000000..d3416c7b4
--- /dev/null
+++ b/lib/sqlalchemy/util/deprecations.py
@@ -0,0 +1,112 @@
+"""Helpers related to deprecation of functions, methods, classes, other
+functionality."""
+
+from sqlalchemy import exc
+import warnings
+import re
+from langhelpers import decorator
+
+def warn_deprecated(msg, stacklevel=3):
+    warnings.warn(msg, exc.SADeprecationWarning, stacklevel=stacklevel)
+
+def warn_pending_deprecation(msg, stacklevel=3):
+    warnings.warn(msg, exc.SAPendingDeprecationWarning, stacklevel=stacklevel)
+
+def deprecated(version, message=None, add_deprecation_to_docstring=True):
+    """Decorates a function and issues a deprecation warning on use.
+
+    :param message:
+      If provided, issue message in the warning.  A sensible default
+      is used if not provided.
+
+    :param add_deprecation_to_docstring:
+      Default True.  If False, the wrapped function's __doc__ is left
+      as-is.  If True, the 'message' is prepended to the docs if
+      provided, or sensible default if message is omitted.
+
+    """
+
+    if add_deprecation_to_docstring:
+        header = ".. deprecated:: %s %s" % \
+                    (version, (message or ''))
+    else:
+        header = None
+
+    if message is None:
+        message = "Call to deprecated function %(func)s"
+
+    def decorate(fn):
+        return _decorate_with_warning(
+            fn, exc.SADeprecationWarning,
+            message % dict(func=fn.__name__), header)
+    return decorate
+
+def pending_deprecation(version, message=None,
+                        add_deprecation_to_docstring=True):
+    """Decorates a function and issues a pending deprecation warning on use.
+
+    :param version:
+      An approximate future version at which point the pending deprecation
+      will become deprecated.  Not used in messaging.
+
+    :param message:
+      If provided, issue message in the warning.  A sensible default
+      is used if not provided.
+
+    :param add_deprecation_to_docstring:
+      Default True.  If False, the wrapped function's __doc__ is left
+      as-is.  If True, the 'message' is prepended to the docs if
+      provided, or sensible default if message is omitted.
+    """
+
+    if add_deprecation_to_docstring:
+        header = ".. deprecated:: %s (pending) %s" % \
+                        (version, (message or ''))
+    else:
+        header = None
+
+    if message is None:
+        message = "Call to deprecated function %(func)s"
+    
+    def decorate(fn):
+        return _decorate_with_warning(
+            fn, exc.SAPendingDeprecationWarning,
+            message % dict(func=fn.__name__), header)
+    return decorate
+
+def _sanitize_restructured_text(text):
+    def repl(m):
+        type_, name = m.group(1, 2)
+        if type_ in ("func", "meth"):
+            name += "()"
+        return name
+    return re.sub(r'\:(\w+)\:`~?\.?(.+?)`', repl, text)
+    
+    
+def _decorate_with_warning(func, wtype, message, docstring_header=None):
+    """Wrap a function with a warnings.warn and augmented docstring."""
+
+    message = _sanitize_restructured_text(message)
+    
+    @decorator
+    def warned(fn, *args, **kwargs):
+        warnings.warn(wtype(message), stacklevel=3)
+        return fn(*args, **kwargs)
+
+    doc = func.__doc__ is not None and func.__doc__ or ''
+    if docstring_header is not None:
+        docstring_header %= dict(func=func.__name__)
+        docs = doc and doc.expandtabs().split('\n') or []
+        indent = ''
+        for line in docs[1:]:
+            text = line.lstrip()
+            if text:
+                indent = line[0:len(line) - len(text)]
+                break
+        point = min(len(docs), 1)
+        docs.insert(point, '\n' + indent + docstring_header.rstrip())
+        doc = '\n'.join(docs)
+
+    decorated = warned(func)
+    decorated.__doc__ = doc
+    return decorated