Ansible blockinfile oddity

pdo debian eng ansible transilience

I was reading Ansible's blockinfile sources for, uhm, reasons, and the code flow looked a bit odd.

So I checked what happens if a file has spurious block markers.

Give this file:

$ cat /tmp/test.orig
line0
# BEGIN ANSIBLE MANAGED BLOCK
line1
# END ANSIBLE MANAGED BLOCK
line2
# END ANSIBLE MANAGED BLOCK
line3
# BEGIN ANSIBLE MANAGED BLOCK
line4

And this playbook:

$ cat test.yaml
---
- hosts: localhost
  tasks:
   - name: test blockinfile
     blockinfile:
        block: NEWLINE
        path: /tmp/test

You get this result:

$ cat /tmp/test
line0
# BEGIN ANSIBLE MANAGED BLOCK
line1
# END ANSIBLE MANAGED BLOCK
line2
# BEGIN ANSIBLE MANAGED BLOCK
NEWLINE
# END ANSIBLE MANAGED BLOCK
line4

I was hoping that I was reading the code incorrectly, but it turns out that Ansible's blockinfile matches the last pair of begin-end markers it finds, in whatever order it finds them.