The earlier code behaved exactly as though this default had been set,
but it was actually handled as a(n unnecessary) special case inside the
connection plugin, rather than set as an explicit default.
If the default is overriden either in ansible.cfg or the environment,
the new code will continue to work (in fact, it won't know or care,
since it just uses the value set in the PlayContext).
This is submitted as a separate commit for easier review to address
backwards-compatibility concerns.
Using set_host_overrides() in the connection plugin to access the ssh
argument variables from the inventory didn't see group_vars/host_vars
settings, as noted earlier. Instead, we can set the correct values in
the PlayContext, which has access to all command-line options, task
settings, and variables.
The only downside of doing so is that the source of the settings is no
longer available in ssh.py, and therefore can't be logged. But the code
is simpler, and it actually works.
This change was suggested by @jimi-c in response to the FIXME in the
earlier commit.
Now we have the following ways to set additional arguments:
1. [ssh_connection]ssh_args in ansible.cfg: global setting, prepended to
every command line for ssh/scp/sftp. Overrides default ControlPersist
settings.
2. ansible_ssh_common_args inventory variable. Appended to every command
line for ssh/scp/sftp. Used in addition to ssh_args, if set above, or
the default settings.
3. ansible_{sftp,scp,ssh}_extra_args inventory variables. Appended to
every command line for the relevant binary only. Used in addition to
#1 and #2, if set above, or the default settings.
3. Using the --ssh-common-args or --{sftp,scp,ssh}-extra-args command
line options (which are overriden by #2 and #3 above).
This preserves backwards compatibility (for ssh_args in ansible.cfg),
but also permits global settings (e.g. ProxyCommand via _common_args) or
ssh-specific options (e.g. -R via ssh_extra_args).
Fixes#12576
<crab> jimi|ansible: do you think it should be possible to add both
foo:22 and foo:23 to the inventory?
<jimi|ansible> no
…so we don't want an invitation to FIXME.
