postgresql_info: fix failure when db/login_db are not specified (ansible-collections#798)

Author: Andersson007

changelogs/fragments/0-postgresql_info.yml

@@ -0,0 +1,2 @@
+bugfixes:
+- postgresql_info - fix failure when a default database is used (neither ``db`` nor ``login_db`` are specified) (https://github.com/ansible-collections/community.postgresql/issues/794).

plugins/modules/postgresql_info.py

@@ -230,9 +230,7 @@ def __init__(self, module, db_conn_obj):
         self.module = module
         self.db_obj = db_conn_obj
         self.cursor = db_conn_obj.connect()
-        self.default_db = module.params['db'] or \
-            module.params['login_db'] or \
-            module.params['database']
+        self.default_db = self.__get_current_db()
         self.pg_info = {
             "version": {},
             "in_recovery": None,
@@ -722,6 +720,13 @@ def __exec_sql(self, query):
             self.cursor.close()
         return False
 
+    def __get_current_db(self):
+        """Get current DB"""
+        # The context is to get the user's default database.
+        # Should be executed right after logging in
+        # https://github.com/ansible-collections/community.postgresql/issues/794
+        return self.__exec_sql('SELECT current_database() AS db')[0]['db']
+
 # ===========================================
 # Module execution.
 #

tests/integration/targets/postgresql_info/tasks/postgresql_info_initial.yml

@@ -148,7 +148,7 @@
   - name: postgresql_info - check filter param passed by list
     <<: *task_parameters
     postgresql_info:
-      <<: *pg_parameters
+      login_user: '{{ pg_user }}'
       login_port: '{{ replica_port }}'
       filter:
         - ver*