Fixed #36894 -- Added TypeError for conflicting arguments in mail APIs.

A TypeError is now raised if fail_silently=True, auth_user, or auth_password
are provided along a connection.

Updated AdminEmailHandler in django.utils.log to remove redundant
fail_silently=True.

Thanks Mike Edmunds for the report and Jacob Tyler Walls for the review.

2 files changed, 34 insertions, 0 deletions

diff --git a/django/core/mail/__init__.py b/django/core/mail/__init__.py
index 4d7f8bf1d9..6a0baa48ed 100644
--- a/django/core/mail/__init__.py
+++ b/django/core/mail/__init__.py
@@ -94,6 +94,17 @@ def send_mail(
     Note: The API for this method is frozen. New code wanting to extend the
     functionality should use the EmailMessage class directly.
     """
+    if connection is not None:
+        if fail_silently:
+            raise TypeError(
+                "fail_silently cannot be used with a connection. "
+                "Pass fail_silently to get_connection() instead."
+            )
+        if auth_user is not None or auth_password is not None:
+            raise TypeError(
+                "auth_user and auth_password cannot be used with a connection. "
+                "Pass auth_user and auth_password to get_connection() instead."
+            )
     connection = connection or get_connection(
         username=auth_user,
         password=auth_password,
@@ -137,6 +148,17 @@ def send_mass_mail(
     Note: The API for this method is frozen. New code wanting to extend the
     functionality should use the EmailMessage class directly.
     """
+    if connection is not None:
+        if fail_silently:
+            raise TypeError(
+                "fail_silently cannot be used with a connection. "
+                "Pass fail_silently to get_connection() instead."
+            )
+        if auth_user is not None or auth_password is not None:
+            raise TypeError(
+                "auth_user and auth_password cannot be used with a connection. "
+                "Pass auth_user and auth_password to get_connection() instead."
+            )
     connection = connection or get_connection(
         username=auth_user,
         password=auth_password,
@@ -158,6 +180,11 @@ def _send_server_message(
     fail_silently=False,
     connection=None,
 ):
+    if connection is not None and fail_silently:
+        raise TypeError(
+            "fail_silently cannot be used with a connection. "
+            "Pass fail_silently to get_connection() instead."
+        )
     recipients = getattr(settings, setting_name)
     if not recipients:
         return
diff --git a/django/core/mail/message.py b/django/core/mail/message.py
index 66d5efeb63..6eb85c6a2a 100644
--- a/django/core/mail/message.py
+++ b/django/core/mail/message.py
@@ -355,6 +355,13 @@ class EmailMessage:
             # Don't bother creating the network connection if there's nobody to
             # send to.
             return 0
+
+        if fail_silently and self.connection:
+            raise TypeError(
+                "fail_silently cannot be used with a connection. "
+                "Pass fail_silently to get_connection() instead."
+            )
+
         return self.get_connection(fail_silently).send_messages([self])
 
     def attach(self, filename=None, content=None, mimetype=None):