bool filter, add booleanization strategy option (#83362)

also make the YAML booleanization the same as spec/JSON/module function
 previous 'aproximation' was missing several options.

Co-authored-by: Abhijeet Kasurde <akasurde@redhat.com>

changelogs/fragments/normalize_booleanization.yml

@@ -0,0 +1,2 @@
+minor_changes:
+  - bool filter now has new strategy option and by default equates YAML 1.1 booleanization, before it just aproximated it.

lib/ansible/plugins/filter/bool.yml

@@ -10,17 +10,31 @@ DOCUMENTATION:
       description: Data to cast.
       type: raw
       required: true
+    strategy:
+      description: Evaluation engine to use while evaluating boolean.
+      default: yaml
+      choices:
+        yaml: Use YAML 1.1 allowed booleans
+        python: Pass through the Python C(bool) function
+        truthy: Just let Python evaluate in an C(if) statement
+      version_added: '2.18'
+  notes:
+    - Before adding the 'strategy' option, evaluation approximated the 'yaml' strategy.
+    - if the value is already a boolean or C(None), this filter returns the original value.
 
 EXAMPLES: |
 
   # in vars
   vars:
     isbool: "{{ (a == b) | bool }} "
-    otherbool: "{{ anothervar | bool }} "
+    otherbool: "{{ anothervar | bool('yaml') }} "
+    yetanotherbool: "{{ pythonbool | bool(strategy='python') }} "
 
   # in a task
   ...
-  when: some_string_value | bool
+  when:
+    - some_string_value | bool
+    - other != notsame
 
 RETURN:
   _value:

lib/ansible/plugins/filter/core.py

@@ -28,6 +28,7 @@ from ansible.module_utils.six import string_types, integer_types, reraise, text_
 from ansible.module_utils.common.text.converters import to_bytes, to_native, to_text
 from ansible.module_utils.common.collections import is_sequence
 from ansible.module_utils.common.yaml import yaml_load, yaml_load_all
+from ansible.module_utils.parsing.convert_bool import boolean
 from ansible.parsing.ajson import AnsibleJSONEncoder
 from ansible.parsing.yaml.dumper import AnsibleDumper
 from ansible.template import recursive_check_defined
@@ -80,14 +81,28 @@ def to_nice_json(a, indent=4, sort_keys=True, *args, **kw):
     return to_json(a, indent=indent, sort_keys=sort_keys, separators=(',', ': '), *args, **kw)
 
 
-def to_bool(a):
+def to_bool(a, strategy='yaml'):
     ''' return a bool for the arg '''
+
+    # nothing to do
     if a is None or isinstance(a, bool):
         return a
-    if isinstance(a, string_types):
+
-        a = a.lower()
+    valid_choices = ('yaml', 'python', 'truthy')
-    if a in ('yes', 'on', '1', 'true', 1):
+    if strategy not in valid_choices:
+        raise AnsibleFilterError(f"Invalid strategy provided ({strategy}), valid choices are: {', '.join(valid_choices)}")
+
+    try:
+        if strategy == 'yaml':
+            # make it lower case for easier matching
+            return boolean(a)
+        if strategy == 'python':
+            return bool(a)
+        if strategy == 'truthy':
+            if a:
                 return True
+    except TypeError as e:
+        raise AnsibleFilterTypeError(f"Could not convert to boolean using strategy {strategy}: {e}", orig_exc=e)
     return False
 
 

test/integration/targets/filter_core/tasks/main.yml

@@ -301,14 +301,28 @@
       - no_match_is_none_inline
       - failure is failed
 
-- name: Verify to_bool
+- name: to_bool
+  tags:
+    - to_bool
+  block:
+  - name: Verify to_bool, using default 'yaml' strategy
     assert:
       that:
         - 'None|bool == None'
         - 'False|bool == False'
         - '"TrUe"|bool == True'
         - '"FalSe"|bool == False'
-      - '7|bool == False'
+
+  - name: non valid bool should fail
+    set_fact:
+      failbool: '{{7|bool}}'
+    register: should_fail
+    ignore_errors: true
+
+  - name: ensure we failed
+    assert:
+      that:
+          - should_fail is failed
 
 - name: Verify to_datetime
   assert: