Add feature to expose vars/defaults with include/import_role (#41330)

* First pass at making 'private' work on include_role, imports are always public

* Prevent dupe task execution and overwriting handlers

* New functionality will use public instead of deprecated private

* Add tests for public exposure

* Validate vars before import/include to ensure they don't expose too early

* Add porting guide docs about public argument and change to import_role

* Add additional docs about public and vars exposure to module docs

* Insert role handlers at parse time, exposing them globally

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

@@ -0,0 +1,56 @@
+---
+- hosts: testhost
+  gather_facts: false
+  roles:
+    - regular
+  tasks:
+    - debug:
+        msg: start tasks
+
+    - name: Static imports should expose vars at parse time, not at execution time
+      assert:
+        that:
+          - static_defaults_var == 'static_defaults'
+          - static_vars_var == 'static_vars'
+    - import_role:
+        name: static
+    - assert:
+        that:
+          - static_tasks_var == 'static_tasks'
+          - static_defaults_var == 'static_defaults'
+          - static_vars_var == 'static_vars'
+
+    - include_role:
+        name: dynamic_private
+    - assert:
+        that:
+          - private_tasks_var == 'private_tasks'
+          - private_defaults_var is undefined
+          - private_vars_var is undefined
+
+    - name: Dynamic include should not expose vars until execution time
+      assert:
+        that:
+          - dynamic_tasks_var is undefined
+          - dynamic_defaults_var is undefined
+          - dynamic_vars_var is undefined
+    - include_role:
+        name: dynamic
+        public: true
+    - assert:
+        that:
+          - dynamic_tasks_var == 'dynamic_tasks'
+          - dynamic_defaults_var == 'dynamic_defaults'
+          - dynamic_vars_var == 'dynamic_vars'
+
+    - include_role:
+        name: from
+        public: true
+        tasks_from: from.yml
+        vars_from: from.yml
+        defaults_from: from.yml
+    - assert:
+        that:
+          - from_tasks_var == 'from_tasks'
+          - from_defaults_var == 'from_defaults'
+          - from_vars_var == 'from_vars'

test/integration/targets/include_import/public_exposure/roles/dynamic/defaults/main.yml

@@ -0,0 +1 @@
+dynamic_defaults_var: dynamic_defaults

test/integration/targets/include_import/public_exposure/roles/dynamic/tasks/main.yml

@@ -0,0 +1,5 @@
+- debug:
+    msg: dynamic
+
+- set_fact:
+    dynamic_tasks_var: dynamic_tasks

test/integration/targets/include_import/public_exposure/roles/dynamic/vars/main.yml

@@ -0,0 +1 @@
+dynamic_vars_var: dynamic_vars

test/integration/targets/include_import/public_exposure/roles/dynamic_private/defaults/main.yml

@@ -0,0 +1 @@
+private_defaults_var: private_defaults

test/integration/targets/include_import/public_exposure/roles/dynamic_private/tasks/main.yml

@@ -0,0 +1,5 @@
+- debug:
+    msg: private
+
+- set_fact:
+    private_tasks_var: private_tasks

test/integration/targets/include_import/public_exposure/roles/dynamic_private/vars/main.yml

@@ -0,0 +1 @@
+private_vars_var: private_vars

test/integration/targets/include_import/public_exposure/roles/from/defaults/from.yml

@@ -0,0 +1 @@
+from_defaults_var: from_defaults

test/integration/targets/include_import/public_exposure/roles/from/tasks/from.yml

@@ -0,0 +1,5 @@
+- debug:
+    msg: from
+
+- set_fact:
+    from_tasks_var: from_tasks

test/integration/targets/include_import/public_exposure/roles/from/vars/from.yml

@@ -0,0 +1 @@
+from_vars_var: from_vars

test/integration/targets/include_import/public_exposure/roles/regular/defaults/main.yml

@@ -0,0 +1 @@
+regular_defaults_var: regular_defaults

test/integration/targets/include_import/public_exposure/roles/regular/tasks/main.yml

@@ -0,0 +1,5 @@
+- debug:
+    msg: regular
+
+- set_fact:
+    regular_tasks_var: regular_tasks

test/integration/targets/include_import/public_exposure/roles/regular/vars/main.yml

@@ -0,0 +1 @@
+regular_vars_var: regular_vars

test/integration/targets/include_import/public_exposure/roles/static/defaults/main.yml

@@ -0,0 +1 @@
+static_defaults_var: static_defaults

test/integration/targets/include_import/public_exposure/roles/static/tasks/main.yml

@@ -0,0 +1,5 @@
+- debug:
+    msg: static
+
+- set_fact:
+    static_tasks_var: static_tasks

test/integration/targets/include_import/public_exposure/roles/static/vars/main.yml

@@ -0,0 +1 @@
+static_vars_var: static_vars

test/integration/targets/include_import/runme.sh

@@ -78,4 +78,6 @@ fi
 ANSIBLE_STRATEGY='linear' ansible-playbook tasks/test_include_dupe_loop.yml -i ../../inventory "$@" | tee test_include_dupe_loop.out
 test "$(grep -c '"item=foo"' test_include_dupe_loop.out)" = 3
 ANSIBLE_STRATEGY='free' ansible-playbook tasks/test_include_dupe_loop.yml -i ../../inventory "$@" | tee test_include_dupe_loop.out
-test "$(grep -c '"item=foo"' test_include_dupe_loop.out)" = 3
+test "$(grep -c '"item=foo"' test_include_dupe_loop.out)" = 3
+
+ansible-playbook public_exposure/playbook.yml -i ../../inventory "$@"