Updates to interpreter discovery for 2.17 (#82420)

changelogs/fragments/clear-distro-interp-map.yml

@@ -0,0 +1,2 @@
+minor_changes:
+- Interpreter Discovery - Remove hardcoded references to specific python interpreters to use for certain distro versions, and modify logic for python3 to become the default.

lib/ansible/config/base.yml

@@ -1553,18 +1553,9 @@ INTERPRETER_PYTHON:
 _INTERPRETER_PYTHON_DISTRO_MAP:
   name: Mapping of known included platform pythons for various Linux distros
   default:
-    redhat:
-      '6': /usr/bin/python
-      '8': /usr/libexec/platform-python
-      '9': /usr/bin/python3
-    debian:
-      '8': /usr/bin/python
-      '10': /usr/bin/python3
-    fedora:
-      '23': /usr/bin/python3
-    ubuntu:
-      '14': /usr/bin/python
-      '16': /usr/bin/python3
+    # Entry only for testing
+    ansible test:
+      '99': /usr/bin/python99
   version_added: "2.8"
   # FUTURE: add inventory override once we're sure it can't be abused by a rogue target
   # FUTURE: add a platform layer to the map so we could use for, eg, freebsd/macos/etc?
@@ -1578,9 +1569,7 @@ INTERPRETER_PYTHON_FALLBACK:
   - python3.8
   - python3.7
   - /usr/bin/python3
-  - /usr/libexec/platform-python
-  - /usr/bin/python
-  - python
+  - python3
   vars:
     - name: ansible_interpreter_python_fallback
   type: list

lib/ansible/executor/interpreter_discovery.py

@@ -53,7 +53,7 @@ def discover_interpreter(action, interpreter_name, discovery_mode, task_vars):
     host = task_vars.get('inventory_hostname', 'unknown')
     res = None
     platform_type = 'unknown'
-    found_interpreters = [u'/usr/bin/python']  # fallback value
+    found_interpreters = [u'/usr/bin/python3']  # fallback value
     is_auto_legacy = discovery_mode.startswith('auto_legacy')
     is_silent = discovery_mode.endswith('_silent')
 
@@ -89,7 +89,7 @@ def discover_interpreter(action, interpreter_name, discovery_mode, task_vars):
                 action._discovery_warnings.append(u'No python interpreters found for '
                                                   u'host {0} (tried {1})'.format(host, bootstrap_python_list))
             # this is lame, but returning None or throwing an exception is uglier
-            return u'/usr/bin/python'
+            return u'/usr/bin/python3'
 
         if platform_type != 'linux':
             raise NotImplementedError('unsupported platform for extended discovery: {0}'.format(to_native(platform_type)))
@@ -106,7 +106,6 @@ def discover_interpreter(action, interpreter_name, discovery_mode, task_vars):
         platform_info = json.loads(res.get('stdout'))
 
         distro, version = _get_linux_distro(platform_info)
-
         if not distro or not version:
             raise NotImplementedError('unable to get Linux distribution/version info')
 
@@ -120,15 +119,15 @@ 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:
+            if platform_interpreter != u'/usr/bin/python3' and u'/usr/bin/python3' in found_interpreters:
                 if not is_silent:
                     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"/usr/bin/python3 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'
+                return u'/usr/bin/python3'
 
         if platform_interpreter not in found_interpreters:
             if platform_interpreter not in bootstrap_python_list:

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

@@ -141,8 +141,6 @@
   - name: debian assertions
     assert:
       that:
-      # Debian 8 and older
-      - auto_out.ansible_facts.discovered_interpreter_python == '/usr/bin/python' and distro_version is version('8', '<=') or distro_version is version('8', '>')
       # Debian 10 and newer
       - auto_out.ansible_facts.discovered_interpreter_python == '/usr/bin/python3' and distro_version is version('10', '>=') or distro_version is version('10', '<')
     when: distro == 'debian'
@@ -150,27 +148,21 @@
   - name: fedora assertions
     assert:
       that:
-      - auto_out.ansible_facts.discovered_interpreter_python == '/usr/bin/python3'
+      - "'/bin/python3' in auto_out.ansible_facts.discovered_interpreter_python"
     when: distro == 'fedora' and distro_version is version('23', '>=')
 
   - name: rhel assertions
     assert:
       that:
-      # rhel 6/7
-      - (auto_out.ansible_facts.discovered_interpreter_python == '/usr/bin/python' and distro_major_version is version('8','<')) or distro_major_version is version('8','>=')
-      # rhel 8
-      - (auto_out.ansible_facts.discovered_interpreter_python == '/usr/libexec/platform-python' and distro_major_version is version('8','==')) or distro_major_version is version('8','!=')
       # rhel 9
-      - (auto_out.ansible_facts.discovered_interpreter_python == '/usr/bin/python3' and distro_major_version is version('9','==')) or distro_major_version is version('9','!=')
+      - ('/bin/python3' in auto_out.ansible_facts.discovered_interpreter_python and distro_major_version is version('9','==')) or distro_major_version is version('9','!=')
     when: distro == 'redhat'
 
   - name: ubuntu assertions
     assert:
       that:
-      # ubuntu < 16
-      - (auto_out.ansible_facts.discovered_interpreter_python == '/usr/bin/python' and distro_version is version('16.04','<')) or distro_version is version('16.04','>=')
       # ubuntu >= 16
-      - (auto_out.ansible_facts.discovered_interpreter_python == '/usr/bin/python3' and distro_version is version('16.04','>=')) or distro_version is version('16.04','<')
+      - ('/bin/python3' in auto_out.ansible_facts.discovered_interpreter_python and distro_version is version('16.04','>=')) or distro_version is version('16.04','<')
     when: distro == 'ubuntu'
 
   - name: mac assertions

test/units/executor/test_interpreter_discovery.py

@@ -12,63 +12,63 @@ from ansible.module_utils.common.text.converters import to_text
 from ansible.errors import AnsibleConnectionFailure
 
 mock_ubuntu_platform_res = to_text(
-    r'{"osrelease_content": "NAME=\"Ubuntu\"\nVERSION=\"16.04.5 LTS (Xenial Xerus)\"\nID=ubuntu\nID_LIKE=debian\n'
-    r'PRETTY_NAME=\"Ubuntu 16.04.5 LTS\"\nVERSION_ID=\"16.04\"\nHOME_URL=\"http://www.ubuntu.com/\"\n'
-    r'SUPPORT_URL=\"http://help.ubuntu.com/\"\nBUG_REPORT_URL=\"http://bugs.launchpad.net/ubuntu/\"\n'
-    r'VERSION_CODENAME=xenial\nUBUNTU_CODENAME=xenial\n", "platform_dist_result": ["Ubuntu", "16.04", "xenial"]}'
+    r'{"osrelease_content": "NAME=\"Ansible Test\"\nVERSION=\"100\"\nID=ansible-test\nID_LIKE=debian\n'
+    r'PRETTY_NAME=\"Ansible Test 100\"\nVERSION_ID=\"100\"\nHOME_URL=\"http://ansible.com/\"\n'
+    r'SUPPORT_URL=\"http://github.com/ansible/ansible\"\nBUG_REPORT_URL=\"http://github.com/ansible/ansible/\"\n'
+    r'VERSION_CODENAME=beans\nUBUNTU_CODENAME=beans\n", "platform_dist_result": ["Ansible Test", "100", "beans"]}'
 )
 
 
 def test_discovery_interpreter_linux_auto_legacy():
-    res1 = u'PLATFORM\nLinux\nFOUND\n/usr/bin/python\n/usr/bin/python3\nENDFOUND'
+    res1 = u'PLATFORM\nLinux\nFOUND\n/usr/bin/python99\n/usr/bin/python3\nENDFOUND'
 
     mock_action = MagicMock()
     mock_action._low_level_execute_command.side_effect = [{'stdout': res1}, {'stdout': mock_ubuntu_platform_res}]
 
     actual = discover_interpreter(mock_action, 'python', 'auto_legacy', {'inventory_hostname': u'host-fóöbär'})
 
-    assert actual == u'/usr/bin/python'
+    assert actual == u'/usr/bin/python3'
     assert len(mock_action.method_calls) == 3
     assert mock_action.method_calls[2][0] == '_discovery_warnings.append'
-    assert u'Distribution Ubuntu 16.04 on host host-fóöbär should use /usr/bin/python3, but is using /usr/bin/python' \
+    assert u'Distribution Ansible Test 100 on host host-fóöbär should use /usr/bin/python99, but is using /usr/bin/python3' \
            u' for backward compatibility' in mock_action.method_calls[2][1][0]
 
 
 def test_discovery_interpreter_linux_auto_legacy_silent():
-    res1 = u'PLATFORM\nLinux\nFOUND\n/usr/bin/python\n/usr/bin/python3\nENDFOUND'
+    res1 = u'PLATFORM\nLinux\nFOUND\n/usr/bin/python3.9\n/usr/bin/python3\nENDFOUND'
 
     mock_action = MagicMock()
     mock_action._low_level_execute_command.side_effect = [{'stdout': res1}, {'stdout': mock_ubuntu_platform_res}]
 
     actual = discover_interpreter(mock_action, 'python', 'auto_legacy_silent', {'inventory_hostname': u'host-fóöbär'})
 
-    assert actual == u'/usr/bin/python'
+    assert actual == u'/usr/bin/python3'
     assert len(mock_action.method_calls) == 2
 
 
 def test_discovery_interpreter_linux_auto():
-    res1 = u'PLATFORM\nLinux\nFOUND\n/usr/bin/python\n/usr/bin/python3\nENDFOUND'
+    res1 = u'PLATFORM\nLinux\nFOUND\n/usr/bin/python99\n/usr/bin/python3\nENDFOUND'
 
     mock_action = MagicMock()
     mock_action._low_level_execute_command.side_effect = [{'stdout': res1}, {'stdout': mock_ubuntu_platform_res}]
 
     actual = discover_interpreter(mock_action, 'python', 'auto', {'inventory_hostname': u'host-fóöbär'})
 
-    assert actual == u'/usr/bin/python3'
+    assert actual == u'/usr/bin/python99'
     assert len(mock_action.method_calls) == 2
 
 
 def test_discovery_interpreter_non_linux():
     mock_action = MagicMock()
     mock_action._low_level_execute_command.return_value = \
-        {'stdout': u'PLATFORM\nDarwin\nFOUND\n/usr/bin/python\nENDFOUND'}
+        {'stdout': u'PLATFORM\nDarwin\nFOUND\n/usr/bin/python3\nENDFOUND'}
 
     actual = discover_interpreter(mock_action, 'python', 'auto_legacy', {'inventory_hostname': u'host-fóöbär'})
 
-    assert actual == u'/usr/bin/python'
+    assert actual == u'/usr/bin/python3'
     assert len(mock_action.method_calls) == 2
     assert mock_action.method_calls[1][0] == '_discovery_warnings.append'
-    assert u'Platform darwin on host host-fóöbär is using the discovered Python interpreter at /usr/bin/python, ' \
+    assert u'Platform darwin on host host-fóöbär is using the discovered Python interpreter at /usr/bin/python3, ' \
            u'but future installation of another Python interpreter could change the meaning of that path' \
            in mock_action.method_calls[1][1][0]
 
@@ -79,7 +79,7 @@ def test_no_interpreters_found():
 
     actual = discover_interpreter(mock_action, 'python', 'auto_legacy', {'inventory_hostname': u'host-fóöbär'})
 
-    assert actual == u'/usr/bin/python'
+    assert actual == u'/usr/bin/python3'
     assert len(mock_action.method_calls) == 2
     assert mock_action.method_calls[1][0] == '_discovery_warnings.append'
     assert u'No python interpreters found for host host-fóöbär (tried' \