From 0f379ec01fbc74e5d3154c144c878bce59eb4992 Mon Sep 17 00:00:00 2001
From: Allen Lavoie <allenl@google.com>
Date: Mon, 13 May 2019 09:22:15 -0700
Subject: [PATCH] Prettier printing for no-matching-signature errors in loaded
 SavedModels

Example (from the unit test):

ValueError: Could not find matching function to call loaded from the SavedModel. Got:
  Positional arguments (2 total):
    * [7, ({'a': <tf.Tensor 'x:0' shape=() dtype=int32>}, <tf.Tensor 'x_1:0' shape=() dtype=int32>)]
    * True
  Keyword arguments: {}

Expected these arguments to match one of the following 1 option(s):

Option 1:
  Positional arguments (2 total):
    * [6, ({u'a': TensorSpec(shape=(), dtype=tf.int32, name=u'x/1/0/a')}, TensorSpec(shape=(), dtype=tf.int32, name=u'x/1/1'))]
    * True
  Keyword arguments: {}

PiperOrigin-RevId: 247948754
---
 .../saved_model/function_deserialization.py   | 26 ++++++++++++++-----
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/tensorflow/python/saved_model/function_deserialization.py b/tensorflow/python/saved_model/function_deserialization.py
index 3c8a58793ba..94618989e4f 100644
--- a/tensorflow/python/saved_model/function_deserialization.py
+++ b/tensorflow/python/saved_model/function_deserialization.py
@@ -234,14 +234,26 @@ def recreate_function(saved_function, concrete_functions):
         if _concrete_function_callable_with(function, inputs, allow_conversion):
           return _call_concrete_function(function, inputs)
 
-    available_signatures = [
-        concrete_functions[function_name].graph.structured_input_signature
-        for function_name in saved_function.concrete_functions
-    ]
+    signature_descriptions = []
+
+    def _pretty_format_positional(positional):
+      return "Positional arguments ({} total):\n    * {}".format(
+          len(positional),
+          "\n    * ".join([str(a) for a in positional]))
+
+    for index, function_name in enumerate(saved_function.concrete_functions):
+      concrete_function = concrete_functions[function_name]
+      positional, keyword = concrete_function.structured_input_signature
+      signature_descriptions.append(
+          "Option {}:\n  {}\n  Keyword arguments: {}"
+          .format(index + 1, _pretty_format_positional(positional), keyword))
     raise ValueError(
-        "Could not find matching function to call for inputs %r. "
-        "Only existing signatures are %r."
-        % (inputs, available_signatures))
+        "Could not find matching function to call loaded from the SavedModel. "
+        "Got:\n  {}\n  Keyword arguments: {}\n\nExpected "
+        "these arguments to match one of the following {} option(s):\n\n{}"
+        .format(_pretty_format_positional(args), kwargs,
+                len(saved_function.concrete_functions),
+                "\n\n".join(signature_descriptions)))
 
   concrete_function_objects = []
   for concrete_function_name in saved_function.concrete_functions: