From 4251f56a4deca276a6ff46acebbb8a46951ff946 Mon Sep 17 00:00:00 2001
From: ybai08 <271969568+ybai08@users.noreply.github.com>
Date: Sat, 17 Oct 2026 12:44:58 -0500
Subject: [PATCH] Return :error when casting malformed datetimes without
 seconds

Strings such as "2015-01-23 ab:50" matched the YYYY-MM-DD HH:MM clause
of the :naive_datetime and :utc_datetime casts, and the nil parts
produced by to_i/1 were passed to NaiveDateTime.new/6, which raised a
FunctionClauseError instead of returning :error. Build the date and
time through the guarded cast_date/3 and cast_time/4 helpers instead.
---
 lib/ecto/type.ex        | 12 ++++++------
 test/ecto/type_test.exs |  6 ++++++
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/lib/ecto/type.ex b/lib/ecto/type.ex
index 243d94dad8..a5b0627fa3 100644
--- a/lib/ecto/type.ex
+++ b/lib/ecto/type.ex
@@ -1179,9 +1179,9 @@ defmodule Ecto.Type do
            minute::2-bytes>>
        )
        when sep in [?\s, ?T] do
-    case NaiveDateTime.new(to_i(year), to_i(month), to_i(day), to_i(hour), to_i(minute), 0) do
-      {:ok, _} = ok -> ok
-      _ -> :error
+    with {:ok, date} <- cast_date(to_i(year), to_i(month), to_i(day)),
+         {:ok, time} <- cast_time(to_i(hour), to_i(minute), 0, nil) do
+      NaiveDateTime.new(date, time)
     end
   end
 
@@ -1232,9 +1232,9 @@ defmodule Ecto.Type do
            minute::2-bytes>>
        )
        when sep in [?\s, ?T] do
-    case NaiveDateTime.new(to_i(year), to_i(month), to_i(day), to_i(hour), to_i(minute), 0) do
-      {:ok, naive_datetime} -> {:ok, DateTime.from_naive!(naive_datetime, "Etc/UTC")}
-      _ -> :error
+    with {:ok, date} <- cast_date(to_i(year), to_i(month), to_i(day)),
+         {:ok, time} <- cast_time(to_i(hour), to_i(minute), 0, nil) do
+      DateTime.new(date, time, "Etc/UTC")
     end
   end
 
diff --git a/test/ecto/type_test.exs b/test/ecto/type_test.exs
index 7174a20e2f..06743295ad 100644
--- a/test/ecto/type_test.exs
+++ b/test/ecto/type_test.exs
@@ -657,6 +657,9 @@ defmodule Ecto.TypeTest do
       assert Ecto.Type.cast(:naive_datetime, "2015-01-23P23:50:07") == :error
       assert Ecto.Type.cast(:naive_datetime, "2015-01-23 23:50.123") == :error
       assert Ecto.Type.cast(:naive_datetime, "2015-01-23 23:50Z") == :error
+      assert Ecto.Type.cast(:naive_datetime, "abcd-01-23 23:50") == :error
+      assert Ecto.Type.cast(:naive_datetime, "2015-01-23 ab:50") == :error
+      assert Ecto.Type.cast(:naive_datetime, "2015-01-23T23:5x") == :error
 
       assert Ecto.Type.cast(:naive_datetime, %{
                "year" => "2015",
@@ -1013,6 +1016,9 @@ defmodule Ecto.TypeTest do
       assert Ecto.Type.cast(:utc_datetime, "2015-01-23P23:50:07") == :error
       assert Ecto.Type.cast(:utc_datetime, "2015-01-23 23:50.123") == :error
       assert Ecto.Type.cast(:utc_datetime, "2015-01-23 23:50Z") == :error
+      assert Ecto.Type.cast(:utc_datetime, "abcd-01-23 23:50") == :error
+      assert Ecto.Type.cast(:utc_datetime, "2015-01-23 ab:50") == :error
+      assert Ecto.Type.cast(:utc_datetime, "2015-01-23T23:5x") == :error
 
       assert Ecto.Type.cast(:utc_datetime, %{
                "year" => "2015",