From 255925938bd7c559af3f7f1ad7b363d34aab28d3 Mon Sep 17 00:00:00 2001
From: Javier <jafermarq@users.noreply.github.com>
Date: Mon, 22 Jan 2024 17:02:31 +0000
Subject: [PATCH] Improve records type checking (#2838)

---
 src/py/flwr/common/configsrecord.py  | 13 +++++++++++--
 src/py/flwr/common/metricsrecord.py  | 13 +++++++++++--
 src/py/flwr/common/recordset_test.py | 10 ++++++++++
 3 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/src/py/flwr/common/configsrecord.py b/src/py/flwr/common/configsrecord.py
index 332269503ac0..b0480841e06c 100644
--- a/src/py/flwr/common/configsrecord.py
+++ b/src/py/flwr/common/configsrecord.py
@@ -87,8 +87,17 @@ def is_valid(value: ConfigsScalar) -> None:
                 # 1s to check 10M element list on a M2 Pro
                 # In such settings, you'd be better of treating such config as
                 # an array and pass it to a ParametersRecord.
-                for list_value in value:
-                    is_valid(list_value)
+                # Empty lists are valid
+                if len(value) > 0:
+                    is_valid(value[0])
+                    # all elements in the list must be of the same valid type
+                    # this is needed for protobuf
+                    value_type = type(value[0])
+                    if not all(isinstance(v, value_type) for v in value):
+                        raise TypeError(
+                            "All values in a list must be of the same valid type. "
+                            f"One of {ConfigsScalar}."
+                        )
             else:
                 is_valid(value)
 
diff --git a/src/py/flwr/common/metricsrecord.py b/src/py/flwr/common/metricsrecord.py
index ecb8eff830ab..e70b0cb31d55 100644
--- a/src/py/flwr/common/metricsrecord.py
+++ b/src/py/flwr/common/metricsrecord.py
@@ -87,8 +87,17 @@ def is_valid(value: MetricsScalar) -> None:
                 # 1s to check 10M element list on a M2 Pro
                 # In such settings, you'd be better of treating such metric as
                 # an array and pass it to a ParametersRecord.
-                for list_value in value:
-                    is_valid(list_value)
+                # Empty lists are valid
+                if len(value) > 0:
+                    is_valid(value[0])
+                    # all elements in the list must be of the same valid type
+                    # this is needed for protobuf
+                    value_type = type(value[0])
+                    if not all(isinstance(v, value_type) for v in value):
+                        raise TypeError(
+                            "All values in a list must be of the same valid type. "
+                            f"One of {MetricsScalar}."
+                        )
             else:
                 is_valid(value)
 
diff --git a/src/py/flwr/common/recordset_test.py b/src/py/flwr/common/recordset_test.py
index 0e4c351647da..83e1e4595f1d 100644
--- a/src/py/flwr/common/recordset_test.py
+++ b/src/py/flwr/common/recordset_test.py
@@ -162,6 +162,7 @@ def test_set_parameters_with_incorrect_types(
         (str, lambda x: float(x.flatten()[0])),  # str: float
         (str, lambda x: x.flatten().astype("int").tolist()),  # str: List[int]
         (str, lambda x: x.flatten().astype("float").tolist()),  # str: List[float]
+        (str, lambda x: []),  # str: empty list
     ],
 )
 def test_set_metrics_to_metricsrecord_with_correct_types(
@@ -203,6 +204,10 @@ def test_set_metrics_to_metricsrecord_with_correct_types(
             str,
             lambda x: [{str(v): v for v in x.flatten()}],
         ),  # str: List[dict[str: float]] (supported: unsupported)
+        (
+            str,
+            lambda x: [1, 2.0, 3.0, 4],
+        ),  # str: List[mixing valid types] (supported: unsupported)
         (
             int,
             lambda x: x.flatten().tolist(),
@@ -278,6 +283,7 @@ def test_set_metrics_to_metricsrecord_with_and_without_keeping_input(
         (str, lambda x: x.flatten().astype("float").tolist()),  # str: List[float]
         (str, lambda x: x.flatten().astype("bool").tolist()),  # str: List[bool]
         (str, lambda x: [x.flatten().tobytes()]),  # str: List[bytes]
+        (str, lambda x: []),  # str: empyt list
     ],
 )
 def test_set_configs_to_configsrecord_with_correct_types(
@@ -310,6 +316,10 @@ def test_set_configs_to_configsrecord_with_correct_types(
             str,
             lambda x: [{str(v): v for v in x.flatten()}],
         ),  # str: List[dict[str: float]] (supported: unsupported)
+        (
+            str,
+            lambda x: [1, 2.0, 3.0, 4],
+        ),  # str: List[mixing valid types] (supported: unsupported)
         (
             int,
             lambda x: x.flatten().tolist(),