Change interpreter discovery defaults to silently prefer Python 3 (#75049)

Push /usr/bin/python to almost the bottom of the barrel. This makes the strategy to prefer
specific versions of the "mystery meat" version.

* Change INTERPRETER_PYTHON default to 'auto'
    Change description to match change in behavior.
    Change deprecation message to a warning.

* Update docs
* Add porting guide entry
* Update unit tests
* Update integration test
* Allow INTERPRETER_PYTHON_FALLBACK to be configure using a variable
* Prefer platform-python above other Python 2 interpreters
* Add Python 3.10 to the list of interpreters

1 files changed, 6 insertions, 9 deletions

diff --git a/lib/ansible/executor/interpreter_discovery.py b/lib/ansible/executor/interpreter_discovery.py
index 28158aedb3..ff14e608d3 100644
--- a/lib/ansible/executor/interpreter_discovery.py
+++ b/lib/ansible/executor/interpreter_discovery.py
@@ -116,16 +116,13 @@ def discover_interpreter(action, interpreter_name, discovery_mode, task_vars):
         # provide a transition period for hosts that were using /usr/bin/python previously (but shouldn't have been)
         if is_auto_legacy:
             if platform_interpreter != u'/usr/bin/python' and u'/usr/bin/python' in found_interpreters:
-                # FIXME: support comments in sivel's deprecation scanner so we can get reminded on this
                 if not is_silent:
-                    action._discovery_deprecation_warnings.append(dict(
-                        msg=u"Distribution {0} {1} on host {2} should use {3}, but is using "
-                            u"/usr/bin/python for backward compatibility with prior Ansible releases. "
-                            u"A future Ansible release will default to using the discovered platform "
-                            u"python for this host. See {4} for more information"
-                            .format(distro, version, host, platform_interpreter,
-                                    get_versioned_doclink('reference_appendices/interpreter_discovery.html')),
-                        version='2.12'))
+                    action._discovery_warnings.append(
+                        u"Distribution {0} {1} on host {2} should use {3}, but is using "
+                        u"/usr/bin/python for backward compatibility with prior Ansible releases. "
+                        u"See {4} for more information"
+                        .format(distro, version, host, platform_interpreter,
+                                get_versioned_doclink('reference_appendices/interpreter_discovery.html')))
                 return u'/usr/bin/python'
 
         if platform_interpreter not in found_interpreters: