referencing variable out of scope

[lavie]

ansible/lib/ansible/module_utils/basic.py

Line 2542 in f2ade09

out_dest = open(dest, 'wb')

In the following code:

            try:
                out_dest = open(dest, 'wb')
                in_src = open(src, 'rb')
                shutil.copyfileobj(in_src, out_dest)
            finally:  # assuring closed files in 2.4 compatible way
                if out_dest:
                    out_dest.close()

If the first open raises an exception, then the if out_dest fails with either a "trying to reference undefined variable" or a "dereferencing variable before assignment" error, depending on the python version I guess. I ran into this corner case in a situation that's a bit hard to recreate while using lineinfile and unsafe writes. However, you can test a simplified version of this code in interactive python to see that the issue does exist (works for me with python 2.7).

SUMMARY

referencing undefined variable

ISSUE TYPE

• Bug Report

COMPONENT NAME

module_utils/basic.py

ANSIBLE VERSION

master

OS / ENVIRONMENT

OSX

STEPS TO REPRODUCE

[ansibot]

@lavie Greetings! Thanks for taking the time to open this issue. In order for the community to handle your issue effectively, we need a bit more information.

Here are the items we could not find in your description:

• issue type
• ansible version
• component name

Please set the description of this issue with this template:
https://raw.githubusercontent.com/ansible/ansible/devel/.github/ISSUE_TEMPLATE.md

click here for bot help

[lavie]

ISSUE TYPE

• Bug Report

COMPONENT NAME

module_utils/basic.py

ANSIBLE VERSION

master

CONFIGURATION

OS / ENVIRONMENT

OSX

SUMMARY

referencing undefined variable

STEPS TO REPRODUCE

ansible/lib/ansible/module_utils/basic.py

Line 2542 in f2ade09

out_dest = open(dest, 'wb')

In the following code:

            try:
                out_dest = open(dest, 'wb')
                in_src = open(src, 'rb')
                shutil.copyfileobj(in_src, out_dest)
            finally:  # assuring closed files in 2.4 compatible way
                if out_dest:
                    out_dest.close()

If the first open raises an exception, then the if out_dest fails with either a "trying to reference undefined variable" or a "dereferencing variable before assignment" error, depending on the python version I guess. I ran into this corner case in a situation that's a bit hard to recreate while using lineinfile and unsafe writes. However, you can test a simplified version of this code in interactive python to see that the issue does exist (works for me with python 2.7).

[alikins]

(I updated the initial bug comment with info from #31786 (comment))

[alikins]

pinging @bcoca, @abadger (basic.py atomic_move/_unsafe_writes)