How to fix AttributeError: 'bytes' object has no attribute 'encode' if using mysql? - mysql

Question

Django development server was running fine using mysql up to yesterday. But today I get the error AttributeError: 'bytes' object has no attribute 'encode'.
I created a new blank django instance by running django-admin startproject newProject. It runs with 'ENGINE': 'django.db.backends.sqlite3'. But produces same error when I change it to 'ENGINE': 'django.db.backends.mysql'
System specification:
os: manjaro linux
virtual environment python version: 3.6
Django version: 2.2
MariaDB version: 10.3.15-1
Have not updated any related package in last 3 days.
The error:
Watching for file changes with StatReloader
Performing system checks...
System check identified no issues (0 silenced).
Exception in thread django-main-thread:
Traceback (most recent call last):
File "/usr/lib64/python3.6/threading.py", line 916, in _bootstrap_inner
self.run()
File "/usr/lib64/python3.6/threading.py", line 864, in run
self._target(*self._args, **self._kwargs)
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/utils/autoreload.py", line 54, in wrapper
fn(*args, **kwargs)
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/core/management/commands/runserver.py", line 120, in inner_run
self.check_migrations()
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/core/management/base.py", line 453, in check_migrations
executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/db/migrations/executor.py", line 18, in __init__
self.loader = MigrationLoader(self.connection)
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/db/migrations/loader.py", line 49, in __init__
self.build_graph()
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/db/migrations/loader.py", line 212, in build_graph
self.applied_migrations = recorder.applied_migrations()
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/db/migrations/recorder.py", line 73, in applied_migrations
if self.has_table():
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/db/migrations/recorder.py", line 56, in has_table
return self.Migration._meta.db_table in self.connection.introspection.table_names(self.connection.cursor())
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/db/backends/base/base.py", line 256, in cursor
return self._cursor()
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/db/backends/base/base.py", line 233, in _cursor
self.ensure_connection()
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/db/backends/base/base.py", line 217, in ensure_connection
self.connect()
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/db/backends/base/base.py", line 197, in connect
self.init_connection_state()
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/db/backends/mysql/base.py", line 232, in init_connection_state
if self.features.is_sql_auto_is_null_enabled:
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/utils/functional.py", line 80, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/db/backends/mysql/features.py", line 82, in is_sql_auto_is_null_enabled
cursor.execute('SELECT ##SQL_AUTO_IS_NULL')
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/db/backends/utils.py", line 103, in execute
sql = self.db.ops.last_executed_query(self.cursor, sql, params)
File "/srv/http/python/env/env36/lib/python3.6/site-packages/django/db/backends/mysql/operations.py", line 147, in last_executed_query
query = query.encode(errors='replace')
AttributeError: 'bytes' object has no attribute 'encode'
How do I fix this ?

Answer 1

Thank to Martijn, I have fixed this.
In the source, stable 2.2 branch line 146 of django/db/backends/mysql/operations.py is
query = query.decode(errors='replace')
In my system path/to/virtualenv/django/db/backends/mysql/operations.py was like
# query = query.decode(errors='replace')
query = query.encode(errors='replace')
I changed it to
query = query.decode(errors='replace')
# query = query.encode(errors='replace')
It is working correctly now.