Allow the "%" character in database name

The naming rules for MySQL/MariaDB identifiers, when quoted, allow the
`%` character.

However, currently, the use of the `%` character in database names
results in mismatch or missing databases.

- Rewrite query to identify the databases in the catalog using
  `information_schema` instead of `SHOW DATABASES LIKE`
- Escape the `%` character in `CREATE DATABASE` query.

Signed-off-by: Nicolas Payart <[email protected]>

changelogs/fragments/227-db-create-special-name.yaml

@@ -0,0 +1,2 @@
+bugfixes:
+  mysql_db - Fix mismatch when database name contains a ``%`` character (https://github.com/ansible-collections/community.mysql/pull/227).

plugins/modules/mysql_db.py

@@ -330,7 +330,7 @@
 def db_exists(cursor, db):
     res = 0
     for each_db in db:
-        res += cursor.execute("SHOW DATABASES LIKE %s", (each_db.replace("_", r"\_"),))
+        res += cursor.execute("SELECT SCHEMA_NAME FROM information_schema.SCHEMATA WHERE SCHEMA_NAME = %s", (each_db,))
     return res == len(db)
 
 
@@ -519,7 +519,8 @@ def db_create(cursor, db, encoding, collation):
     query_params = dict(enc=encoding, collate=collation)
     res = 0
     for each_db in db:
-        query = ['CREATE DATABASE %s' % mysql_quote_identifier(each_db, 'database')]
+        # Escape '%' since mysql cursor.execute() uses a format string
+        query = ['CREATE DATABASE %s' % mysql_quote_identifier(each_db, 'database').replace('%', '%%')]
         if encoding:
             query.append("CHARACTER SET %(enc)s")
         if collation:

tests/integration/targets/test_mysql_db/tasks/db_create_special.yml

@@ -0,0 +1,86 @@
+# test code for mysql_db module with database name containing special chars
+# (c) 2021,  Nicolas Payart <[email protected]>
+
+# This file is part of Ansible
+#
+# Ansible is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Ansible is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
+
+# ============================================================
+- name: "Set db_name to db%"
+  set_fact:
+    db_name: "db%"
+
+- name: remove database if it exists
+  command: >
+    "{{ mysql_command }} -sse 'drop database {{ db_name }}'"
+  ignore_errors: True
+
+- name: make sure the test database is not there
+  command: "{{ mysql_command }} {{ db_name }}"
+  register: mysql_db_check
+  failed_when: "'1049' not in mysql_db_check.stderr"
+
+- name: test state=present for a database name (expect changed=true)
+  mysql_db:
+    login_user: '{{ mysql_user }}'
+    login_password: '{{ mysql_password }}'
+    login_host: 127.0.0.1
+    login_port: '{{ mysql_primary_port }}'
+    name: '{{ db_name }}'
+    state: present
+  register: result
+
+- name: assert output message that database exist
+  assert:
+    that:
+      - result is changed
+      - result.db == '{{ db_name }}'
+      - result.executed_commands == ["CREATE DATABASE `{{ db_name }}`"]
+
+- name: run command to test state=present for a database name (expect db_name in stdout)
+  command: "{{ mysql_command }} -e \"show databases like '{{ db_name | regex_replace(\"([%_\\\\])\", \"\\\\\\1\") }}'\""
+  register: result
+
+- name: assert database exist
+  assert:
+    that:
+      - "'{{ db_name }}' in result.stdout"
+
+# ============================================================
+- name: test state=absent for a database name (expect changed=true)
+  mysql_db:
+    login_user: '{{ mysql_user }}'
+    login_password: '{{ mysql_password }}'
+    login_host: 127.0.0.1
+    login_port: '{{ mysql_primary_port }}'
+    name: '{{ db_name }}'
+    state: absent
+  register: result
+
+- name: assert output message that database does not exist
+  assert:
+    that:
+      - result is changed
+      - result.db == '{{ db_name }}'
+      - result.executed_commands == ["DROP DATABASE `{{ db_name }}`"]
+
+- name: run command to test state=absent for a database name (expect db_name not in stdout)
+  command: "{{ mysql_command }} -e \"show databases like '{{ db_name | regex_replace(\"([%_\\\\])\", \"\\\\\\1\") }}'\""
+  register: result
+
+- name: assert database does not exist
+  assert:
+    that:
+      - "'{{ db_name }}' not in result.stdout"
+

tests/integration/targets/test_mysql_db/tasks/main.yml

@@ -324,3 +324,6 @@
   when: ansible_python.version_info[0] >= 3
 
 - include: issue-28.yml
+
+- include: db_create_special.yml
+