[WIP] allow users to 'undefine' a variable

[bcoca]

fixes #24136

ISSUE TYPE

• Feature Pull Request

COMPONENT NAME

core

[agaffney]

While not necessary to add here, it would be nice to have a corresponding unset_fact action with the same behavior.

[ansibot]

The test ansible-test sanity --test ansible-doc [explain] failed with the error:

Command "ansible-doc -t become runas su sudo" returned exit status 250.
>>> Standard Error
ERROR! Unexpected Exception, this is probably a bug: cannot import name 'filter_loader'

The test ansible-test sanity --test docs-build [explain] failed with the error:

Command "/usr/bin/python3.6 /root/ansible/test/sanity/code-smell/docs-build.py" returned exit status 1.
>>> Standard Error
Command 'make base_singlehtmldocs' failed with status code: 2
--> Standard Output
../../hacking/build-ansible.py collection-meta --template-file=../templates/collections_galaxy_meta.rst.j2 --output-dir=rst/dev_guide/ ../../lib/ansible/galaxy/data/collections_galaxy_meta.yml
../../hacking/build-ansible.py document-config --template-file=../templates/config.rst.j2 --output-dir=rst/reference_appendices/ ../../lib/ansible/config/base.yml
mkdir -p rst/cli
../../hacking/build-ansible.py generate-man --template-file=../templates/cli_rst.j2 --output-dir=rst/cli/ --output-format rst ../../lib/ansible/cli/*.py
Makefile:109: recipe for target 'cli' failed
--> Standard Error
Traceback (most recent call last):
  File "../../hacking/build-ansible.py", line 103, in <module>
    main()
  File "../../hacking/build-ansible.py", line 92, in main
    retval = command.main(args)
  File "/root/ansible/hacking/build_library/build_ansible/command_plugins/generate_man.py", line 279, in main
    allvars[cli_name] = opts_docs(cli_class_name, cli_name)
  File "/root/ansible/hacking/build_library/build_ansible/command_plugins/generate_man.py", line 120, in opts_docs
    fromlist=[cli_class_name]), cli_class_name)
  File "/root/ansible/lib/ansible/cli/__init__.py", line 21, in <module>
    from ansible.inventory.manager import InventoryManager
  File "/root/ansible/lib/ansible/inventory/manager.py", line 38, in <module>
    from ansible.plugins.loader import inventory_loader
  File "/root/ansible/lib/ansible/plugins/loader.py", line 23, in <module>
    from ansible.parsing.utils.yaml import from_yaml
  File "/root/ansible/lib/ansible/parsing/utils/yaml.py", line 17, in <module>
    from ansible.parsing.yaml.loader import AnsibleLoader
  File "/root/ansible/lib/ansible/parsing/yaml/loader.py", line 30, in <module>
    from ansible.parsing.yaml.constructor import AnsibleConstructor
  File "/root/ansible/lib/ansible/parsing/yaml/constructor.py", line 30, in <module>
    from ansible.template import AnsibleUndefined
  File "/root/ansible/lib/ansible/template/__init__.py", line 52, in <module>
    from ansible.plugins.loader import filter_loader, lookup_loader, test_loader
ImportError: cannot import name 'filter_loader'
make: *** [cli] Error 1

The test ansible-test sanity --test package-data [explain] failed with the error:

Command "/usr/bin/python3.6 /root/ansible/test/sanity/code-smell/package-data.py" returned exit status 1.
>>> Standard Error
Traceback (most recent call last):
  File "/root/ansible/test/sanity/code-smell/package-data.py", line 376, in <module>
    main()
  File "/root/ansible/test/sanity/code-smell/package-data.py", line 353, in main
    sdist_path = create_sdist(tmp_dir)
  File "/root/ansible/test/sanity/code-smell/package-data.py", line 167, in create_sdist
    raise Exception('make snapshot failed:\n%s' % stderr)
Exception: make snapshot failed:
fatal: not a git repository (or any parent up to mount point /)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
fatal: not a git repository (or any parent up to mount point /)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
fatal: not a git repository (or any parent up to mount point /)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
Traceback (most recent call last):
  File "hacking/build-ansible.py", line 103, in <module>
    main()
  File "hacking/build-ansible.py", line 92, in main
    retval = command.main(args)
  File "/tmp/tmpcxt6t8fl/hacking/build_library/build_ansible/command_plugins/generate_man.py", line 279, in main
    allvars[cli_name] = opts_docs(cli_class_name, cli_name)
  File "/tmp/tmpcxt6t8fl/hacking/build_library/build_ansible/command_plugins/generate_man.py", line 120, in opts_docs
    fromlist=[cli_class_name]), cli_class_name)
  File "/tmp/tmpcxt6t8fl/lib/ansible/cli/__init__.py", line 21, in <module>
    from ansible.inventory.manager import InventoryManager
  File "/tmp/tmpcxt6t8fl/lib/ansible/inventory/manager.py", line 38, in <module>
    from ansible.plugins.loader import inventory_loader
  File "/tmp/tmpcxt6t8fl/lib/ansible/plugins/loader.py", line 23, in <module>
    from ansible.parsing.utils.yaml import from_yaml
  File "/tmp/tmpcxt6t8fl/lib/ansible/parsing/utils/yaml.py", line 17, in <module>
    from ansible.parsing.yaml.loader import AnsibleLoader
  File "/tmp/tmpcxt6t8fl/lib/ansible/parsing/yaml/loader.py", line 30, in <module>
    from ansible.parsing.yaml.constructor import AnsibleConstructor
  File "/tmp/tmpcxt6t8fl/lib/ansible/parsing/yaml/constructor.py", line 30, in <module>
    from ansible.template import AnsibleUndefined
  File "/tmp/tmpcxt6t8fl/lib/ansible/template/__init__.py", line 52, in <module>
    from ansible.plugins.loader import filter_loader, lookup_loader, test_loader
ImportError: cannot import name 'filter_loader'
make: *** [generate_rst] Error 1

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[someone-somenet-org]

When merge? :)

(Just came across an issue with our scripts which would easily be solved by unsetting some vars)

[SCLogo]

Any update on this? Unset a variable in our playbook could simplify the code...