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1 files changed, 185 insertions, 0 deletions

diff --git a/lib/sqlalchemy/event/legacy.py b/lib/sqlalchemy/event/legacy.py
new file mode 100644
index 0000000..d9f6ce5
--- /dev/null
+++ b/lib/sqlalchemy/event/legacy.py
@@ -0,0 +1,185 @@
+# event/legacy.py
+# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+"""Routines to handle adaption of legacy call signatures,
+generation of deprecation notes and docstrings.
+
+"""
+
+from .. import util
+
+
+def _legacy_signature(since, argnames, converter=None):
+    def leg(fn):
+        if not hasattr(fn, "_legacy_signatures"):
+            fn._legacy_signatures = []
+        fn._legacy_signatures.append((since, argnames, converter))
+        return fn
+
+    return leg
+
+
+def _wrap_fn_for_legacy(dispatch_collection, fn, argspec):
+    for since, argnames, conv in dispatch_collection.legacy_signatures:
+        if argnames[-1] == "**kw":
+            has_kw = True
+            argnames = argnames[0:-1]
+        else:
+            has_kw = False
+
+        if len(argnames) == len(argspec.args) and has_kw is bool(
+            argspec.varkw
+        ):
+
+            formatted_def = "def %s(%s%s)" % (
+                dispatch_collection.name,
+                ", ".join(dispatch_collection.arg_names),
+                ", **kw" if has_kw else "",
+            )
+            warning_txt = (
+                'The argument signature for the "%s.%s" event listener '
+                "has changed as of version %s, and conversion for "
+                "the old argument signature will be removed in a "
+                'future release.  The new signature is "%s"'
+                % (
+                    dispatch_collection.clsname,
+                    dispatch_collection.name,
+                    since,
+                    formatted_def,
+                )
+            )
+
+            if conv:
+                assert not has_kw
+
+                def wrap_leg(*args):
+                    util.warn_deprecated(warning_txt, version=since)
+                    return fn(*conv(*args))
+
+            else:
+
+                def wrap_leg(*args, **kw):
+                    util.warn_deprecated(warning_txt, version=since)
+                    argdict = dict(zip(dispatch_collection.arg_names, args))
+                    args = [argdict[name] for name in argnames]
+                    if has_kw:
+                        return fn(*args, **kw)
+                    else:
+                        return fn(*args)
+
+            return wrap_leg
+    else:
+        return fn
+
+
+def _indent(text, indent):
+    return "\n".join(indent + line for line in text.split("\n"))
+
+
+def _standard_listen_example(dispatch_collection, sample_target, fn):
+    example_kw_arg = _indent(
+        "\n".join(
+            "%(arg)s = kw['%(arg)s']" % {"arg": arg}
+            for arg in dispatch_collection.arg_names[0:2]
+        ),
+        "    ",
+    )
+    if dispatch_collection.legacy_signatures:
+        current_since = max(
+            since
+            for since, args, conv in dispatch_collection.legacy_signatures
+        )
+    else:
+        current_since = None
+    text = (
+        "from sqlalchemy import event\n\n\n"
+        "@event.listens_for(%(sample_target)s, '%(event_name)s')\n"
+        "def receive_%(event_name)s("
+        "%(named_event_arguments)s%(has_kw_arguments)s):\n"
+        "    \"listen for the '%(event_name)s' event\"\n"
+        "\n    # ... (event handling logic) ...\n"
+    )
+
+    text %= {
+        "current_since": " (arguments as of %s)" % current_since
+        if current_since
+        else "",
+        "event_name": fn.__name__,
+        "has_kw_arguments": ", **kw" if dispatch_collection.has_kw else "",
+        "named_event_arguments": ", ".join(dispatch_collection.arg_names),
+        "example_kw_arg": example_kw_arg,
+        "sample_target": sample_target,
+    }
+    return text
+
+
+def _legacy_listen_examples(dispatch_collection, sample_target, fn):
+    text = ""
+    for since, args, conv in dispatch_collection.legacy_signatures:
+        text += (
+            "\n# DEPRECATED calling style (pre-%(since)s, "
+            "will be removed in a future release)\n"
+            "@event.listens_for(%(sample_target)s, '%(event_name)s')\n"
+            "def receive_%(event_name)s("
+            "%(named_event_arguments)s%(has_kw_arguments)s):\n"
+            "    \"listen for the '%(event_name)s' event\"\n"
+            "\n    # ... (event handling logic) ...\n"
+            % {
+                "since": since,
+                "event_name": fn.__name__,
+                "has_kw_arguments": " **kw"
+                if dispatch_collection.has_kw
+                else "",
+                "named_event_arguments": ", ".join(args),
+                "sample_target": sample_target,
+            }
+        )
+    return text
+
+
+def _version_signature_changes(parent_dispatch_cls, dispatch_collection):
+    since, args, conv = dispatch_collection.legacy_signatures[0]
+    return (
+        "\n.. deprecated:: %(since)s\n"
+        "    The :class:`.%(clsname)s.%(event_name)s` event now accepts the \n"
+        "    arguments ``%(named_event_arguments)s%(has_kw_arguments)s``.\n"
+        "    Support for listener functions which accept the previous \n"
+        '    argument signature(s) listed above as "deprecated" will be \n'
+        "    removed in a future release."
+        % {
+            "since": since,
+            "clsname": parent_dispatch_cls.__name__,
+            "event_name": dispatch_collection.name,
+            "named_event_arguments": ", ".join(dispatch_collection.arg_names),
+            "has_kw_arguments": ", **kw" if dispatch_collection.has_kw else "",
+        }
+    )
+
+
+def _augment_fn_docs(dispatch_collection, parent_dispatch_cls, fn):
+    header = (
+        ".. container:: event_signatures\n\n"
+        "     Example argument forms::\n"
+        "\n"
+    )
+
+    sample_target = getattr(parent_dispatch_cls, "_target_class_doc", "obj")
+    text = header + _indent(
+        _standard_listen_example(dispatch_collection, sample_target, fn),
+        " " * 8,
+    )
+    if dispatch_collection.legacy_signatures:
+        text += _indent(
+            _legacy_listen_examples(dispatch_collection, sample_target, fn),
+            " " * 8,
+        )
+
+        text += _version_signature_changes(
+            parent_dispatch_cls, dispatch_collection
+        )
+
+    return util.inject_docstring_text(fn.__doc__, text, 1)