Fix incorrect "Could not match supplied host pattern" warning (#66764) (#67432)

changelogs/fragments/66764-host-pattern-warning.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - Fix incorrect "Could not match supplied host pattern" warning (https://github.com/ansible/ansible/issues/66764)

lib/ansible/playbook/play.py

@@ -53,7 +53,7 @@ class Play(Base, Taggable, CollectionSearch):
     """
 
     # =================================================================================
-    _hosts = FieldAttribute(isa='list', required=True, listof=string_types, always_post_validate=True)
+    _hosts = FieldAttribute(isa='list', required=True, listof=string_types, always_post_validate=True, priority=-1)
 
     # Facts
     _gather_facts = FieldAttribute(isa='bool', default=None, always_post_validate=True)

test/integration/targets/include_import/empty_group_warning/playbook.yml

@@ -0,0 +1,13 @@
+---
+- hosts: localhost
+  gather_facts: false
+  tasks:
+    - name: Group
+      group_by:
+        key: test_{{ inventory_hostname }}
+
+- hosts: test_localhost
+  gather_facts: false
+  tasks:
+    - name: Print
+      import_tasks: tasks.yml

test/integration/targets/include_import/empty_group_warning/tasks.yml

@@ -0,0 +1,3 @@
+- name: test
+  debug:
+    msg: hello

test/integration/targets/include_import/runme.sh

@@ -108,3 +108,6 @@ ansible-playbook valid_include_keywords/playbook.yml "$@"
 # https://github.com/ansible/ansible/issues/64902
 ansible-playbook tasks/test_allow_single_role_dup.yml 2>&1 | tee test_allow_single_role_dup.out
 test "$(grep -c 'ok=3' test_allow_single_role_dup.out)" = 1
+
+# https://github.com/ansible/ansible/issues/66764
+ANSIBLE_HOST_PATTERN_MISMATCH=error ansible-playbook empty_group_warning/playbook.yml