upgrade from 2.3 to 2.4 breaks vars loading when using 'path' as inventory_hostname

[ksmets]

ISSUE TYPE

• Bug Report

COMPONENT NAME

chroot

ANSIBLE VERSION

ansible 2.4.1.0
  config file = /home/ksmets/my-ansible-playbooks/ansible.cfg
  configured module search path = [u'/home/ksmets/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /home/ksmets/.virtualenvs/ansible/local/lib/python2.7/site-packages/ansible
  executable location = /home/ksmets/.virtualenvs/ansible/bin/ansible
  python version = 2.7.11+ (default, Apr 17 2016, 14:00:29) [GCC 5.3.1 20160413]

CONFIGURATION

OS / ENVIRONMENT

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04.3 LTS"

Linux midgard 4.4.0-98-generic #121-Ubuntu SMP Tue Oct 10 14:24:03 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

SUMMARY

After upgrading from a 2.3-release (i.e. 2.3.2.0) to the latest 2.4-release (i.e. 2.4.1.0) the chroot connection plugin no longer works.

STEPS TO REPRODUCE

---
# file: build-rpi-sd-card.yml

- hosts: localhost
  vars:
    rasbian_version: 2017-09-07-raspbian-stretch-lite
    rasbian_mountpoint: /mnt/rpi
  pre_tasks:
  - name: install required packages
    apt:
      name: "{{ item }}"
      state: present
    with_items:
    - qemu
    - qemu-user-static
    - binfmt-support
  tasks:
  - name: download rasbian
    get_url:
      url: http://downloads.raspberrypi.org/raspbian_lite/images/raspbian_lite-2017-09-08/{{ rasbian_version }}.zip
      dest: ~/Downloads/{{ rasbian_version }}.zip

  - name: extract rasbian image
    unarchive:
      src: ~/Downloads/{{ rasbian_version }}.zip
      dest: /dev/shm
      creates: /dev/shm/{{ rasbian_version }}.img

  - name: get the name of the first unused loop device
    command: losetup --find
    register: result
    changed_when: False

  - name: register the name of the first unused loop device
    set_fact:
      loopdev: "{{ result.stdout }}"

  - name: set up the loop device
    command: losetup --partscan {{ loopdev }} /dev/shm/{{ rasbian_version }}.img creates={{ loopdev }}p*

  - name: ensure the mount point exists
    file:
      path: "{{ rasbian_mountpoint }}"
      state: directory

  - name: mount the root partition
    command: mount {{ loopdev }}p2 {{ rasbian_mountpoint }} creates={{ rasbian_mountpoint }}/boot warn=no

  - name: mount the boot partition
    command: mount {{ loopdev }}p1 {{ rasbian_mountpoint }}/boot creates={{ rasbian_mountpoint }}/boot/kernel.img warn=no

  - name: copy qemu-arm-static
    copy:
      src: /usr/bin/qemu-arm-static
      dest: "{{ rasbian_mountpoint }}/usr/bin/qemu-arm-static"
      mode: 0755

  - name: comment line in /etc/ld.so.preload
    lineinfile:
      path: "{{ rasbian_mountpoint }}/etc/ld.so.preload"
      regexp: '/usr/lib/arm-linux-gnueabihf/libarmmem.so'
      line: '#/usr/lib/arm-linux-gnueabihf/libarmmem.so'

  - name: add {{ rasbian_mountpoint }} to chroots group
    add_host:
      name: "{{ rasbian_mountpoint }}"
      groups: chroots

- hosts: chroots
  connection: chroot
  tasks:
  - ping:

- hosts: localhost
  vars:
    rasbian_mountpoint: /mnt/rpi
  tasks:
  - name: uncomment line in /etc/ld.so.preload
    lineinfile:
      path: "{{ rasbian_mountpoint }}/etc/ld.so.preload"
      regexp: '#/usr/lib/arm-linux-gnueabihf/libarmmem.so'
      line: '/usr/lib/arm-linux-gnueabihf/libarmmem.so'

  - name: remove qemu-arm-static
    file:
      path: "{{ rasbian_mountpoint }}/usr/bin/qemu-arm-static"
      state: absent

  - name: unmount the boot partition
    command: umount {{ rasbian_mountpoint }}/boot removes={{ rasbian_mountpoint }}/boot/kernel.img

  - name: unmount the root partition
    command: umount {{ rasbian_mountpoint }} removes={{ rasbian_mountpoint }}/boot

  - name: ensure the mount point doesn't exist
    file:
      path: "{{ rasbian_mountpoint }}"
      state: absent

  - name: detach the loop device
    command: losetup --detach {{ loopdev }} removes={{ loopdev }}p*

EXPECTED RESULTS

sudo ansible -c chroot -i /mnt/rpi, -m ping all
/mnt/rpi | SUCCESS => {
    "changed": false, 
    "ping": "pong"
}

ACTUAL RESULTS

sudo ansible -c chroot -i /mnt/rpi, -m ping all -vvvv

ansible 2.4.1.0
  config file = /home/ksmets/my-ansible-playbooks/ansible.cfg
  configured module search path = [u'/home/ksmets/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /home/ksmets/.virtualenvs/ansible/local/lib/python2.7/site-packages/ansible
  executable location = /home/ksmets/.virtualenvs/ansible/bin/ansible
  python version = 2.7.11+ (default, Apr 17 2016, 14:00:29) [GCC 5.3.1 20160413]
Using /home/ksmets/my-ansible-playbooks/ansible.cfg as config file
setting up inventory plugins
Unable to parse address from hostname, leaving unchanged: Not a valid network hostname: /mnt/rpi
Parsed /mnt/rpi, inventory source with host_list plugin
Loading callback plugin minimal of type stdout, v2.0 from /home/ksmets/.virtualenvs/ansible/local/lib/python2.7/site-packages/ansible/plugins/callback/__init__.pyc
META: ran handlers
ERROR! Syntax Error while loading YAML.


The error appears to have been in '/mnt/rpi/etc/dhcp/debug': line 12, column 1, but may
be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

if [ "$RUN" = "yes" ]; then
	echo "$(date): entering ${1%/*}, dumping variables." \
^ here
There appears to be a tab character at the start of the line.

YAML does not use tabs for formatting. Tabs should be replaced with spaces.

For example:
    - name: update tooling
      vars:
        version: 1.2.3
#    ^--- there is a tab there.

Should be written as:
    - name: update tooling
      vars:
        version: 1.2.3
# ^--- all spaces here.

exception type: <class 'yaml.scanner.ScannerError'>
exception: while scanning for the next token
found character '\t' that cannot start any token
  in "<unicode string>", line 12, column 1:
    	echo "$(date): entering ${1%/*} ... 
    ^

[bcoca]

its not the chroot plugin that breaks here, its 'host_vars loading' as the inventory hostname is valid path and the vars plugin finds a file but it fails to parse it.

This should workaround it for now:

ansible -c chroot -i rpi_host, -m ping all -e 'ansible_host=/mnt/rpi

[bcoca]

@ksmets please confirm that the PR above resolves the issue for you

[ksmets]

Thx @bcoca, PR #32778 fixes this problem.