# Inconsistent expression evaluation

**URL:** <https://forum.ansible.com/t/inconsistent-expression-evaluation/40816>\
**Category:** Get Help\
**Tags:** jinja2\
**Created:** [March 6, 2025, 10:51am UTC](https://forum.ansible.com/t/inconsistent-expression-evaluation/40816 "2025-03-06T10:51:33Z")\
**Posts on this page:** 7\
**Page:** 1

<div class="post-metadata">

**Author:** ![vbotka](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/vbotka/32/359_2.png) [@vbotka](https://forum.ansible.com/u/vbotka)\
**Post date:** [March 6, 2025, 10:51am UTC](https://forum.ansible.com/t/inconsistent-expression-evaluation/40816/1 "2025-03-06T10:51:33Z")

</div>

- The below expressions are valid YAML dictionaries

```yaml
{"socket": "test"}
{socket: "test"}

```

- They become valid YAML strings if you quote them

```yaml
'{"socket": "test"}'
'{socket: "test"}'

```

- When you put a substitution into the expression, given the variable

```yaml
test_var: test

```

the below expression evaluates to a **string**

```yaml
'{socket: "{{ test_var }}"}'

```

, but if the ‘key’ is quoted

```yaml
'{"socket": "{{ test_var }}"}'

```

it evaluates to a **dictionary**

- The evaluation becomes weirder when you append a comma. The string remains a string

```yaml
'{socket: "{{ test_var }}"},'

```

, but the dictionary becomes a list with a single item `[{'socket': 'test'}]`

```yaml
'{"socket": "{{ test_var }}"},'

```

- In addition to this. If you write it to a file

```yaml
    - copy:
        dest: /tmp/test.txt
        content: |
          {"socket": "{{test_var}}"},

```

you get a **set**

```yaml
shell> cat /tmp/test.txt 
({'socket': 'test'},)

```

Is this a bug?

If it isn’t a bug can you point me to a docs that explain this?

Example of a complete playbook for testing

```yaml
- hosts: localhost

  vars:

    test_var: test
  
  tasks:

    - debug:
        msg: |
          x: {{ item }}
          type(x): {{ item | type_debug }}
      loop:
        - {"socket": "test"}
        - {socket: "test"}
        - '{"socket": "test"}'
        - '{socket: "test"}'
        - '{"socket": "{{ test_var }}"}'
        - '{socket: "{{ test_var }}"}'
        - '{"socket": "{{ test_var }}"},'
        - '{socket: "{{ test_var }}"},'

```

---

<div class="post-metadata">

**Author:** ![sivel](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/sivel/32/1198_2.png) [@sivel](https://forum.ansible.com/u/sivel)\
**Post date:** [March 6, 2025, 2:59pm UTC](https://forum.ansible.com/t/inconsistent-expression-evaluation/40816/2 "2025-03-06T14:59:03Z")

</div>

This isn’t a bug, it’s just a side effect of how templating works, and the implementation historically necessary to get jinja2 to be able to provide python data types, instead of just strings. See:

> <https://github.com/ansible/ansible/issues/34595#issuecomment-356091161>
>
> \##### ISSUE TYPE
> - Bug Report
> 
> \##### COMPONENT NAME
> copy\_module
> 
> \##### AN…SIBLE VERSION
> 
> \`\`\`
> ansible 2.5.0 (devel 34206a0402) last updated 2018/01/08 18:52:56 (GMT +000)
> config file = None
> configured module search path = \['/home/ubuntu/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules'\]
> ansible python module location = /home/ubuntu/ansible/lib/ansible
> executable location = /home/ubuntu/ansible/bin/ansible
> python version = 3.5.2 (default, Nov 23 2017, 16:37:01) \[GCC 5.4.0 20160609\]
> \`\`\`
> 
> also seen on:
> 
> \`\`\`
> ansible 2.4.2.0
> config file = /etc/ansible/ansible.cfg
> configured module search path = \['/home/brian/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules'\]
> ansible python module location = /home/brian/.virtualenvs/mypy/lib/python3.5/site-packages/ansible
> executable location = /home/brian/.virtualenvs/mypy/bin/ansible
> python version = 3.5.2 (default, Nov 17 2016, 17:05:23) \[GCC 5.4.0 20160609\]
> \`\`\`
> 
> \##### CONFIGURATION
> 
> \`\`\`
> (ansible-test) ubuntu@ubuntu-xenial:~/ansible$ ansible-config dump --only-changed
> (ansible-test) ubuntu@ubuntu-xenial:~/ansible$ 
> \`\`\`
> 
> (no output -- no changes to ansible.cfg, this is a clean ubuntu 16.04 VM with python, pip, virtualenv, a clone of the ansible repo, and \`pip -r requirements.txt\`)
> 
> \##### OS / ENVIRONMENT
> 
> ubuntu 16.04, managing itself
> 
> \##### SUMMARY
> 
> When running under python 3, using copy.content with literal json and a variable in the input, the output varies from run to run (the dict keys are being reordered arbitrarily).
> 
> \##### STEPS TO REPRODUCE
> 
> 
> 
> Run the playbook below with:
> 
> \`\`\`
> ansible-playbook -i localhost, playbook.yaml
> \`\`\`
> 
> \`\`\`yaml
> \---
> \- hosts: localhost
> connection: local
> gather\_facts: false
> 
> vars:
> my\_var: a\_value
> 
> tasks:
> - copy:
> dest: ./output.txt
> content: |
> {
> "key1": "{{ my\_var }}",
> "key2": "something else",
> "key3": "something different",
> "key4": "completely different",
> "key5": "1.2.3"
> }
> \`\`\`
> 
> Note in the example playbook:
> 
> 1. This only seems to happen when using a variable (static content didn't show this behavior).
> 2. This only seems to happen when the input is json (yaml didn't show this behavior).
> 
> 
> 
> \##### EXPECTED RESULTS
> 
> 
> 1. The provided input should be output in the same format (i.e. without having whitespace rearranged).
> 2. The provided input should not be reordered (i.e. dict keys should not "move around").
> 3. (As a corollary to 2) The playbook should yield changed=0 on the second run -- the output file should not be modified.
> 
> \##### ACTUAL RESULTS
> 
> 
> 
> 
> See example run below.
> 
> Note that:
> 
> 1. The input has been reformatted onto a single line.
> 2. The keys are reordered from the input.
> 3. The file changes on every run.
> 
> \`\`\`
> (ansible-test) ubuntu@ubuntu-xenial:~/ansible$ ansible-playbook -i localhost, playbook.yaml 
> 
> PLAY \[localhost\] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
> 
> TASK \[copy\] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
> changed: \[localhost\]
> 
> PLAY RECAP \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
> localhost : ok=1 changed=1 unreachable=0 failed=0   
> 
> (ansible-test) ubuntu@ubuntu-xenial:~/ansible$ cat output.txt 
> {"key1": "a\_value", "key2": "something else", "key5": "1.2.3", "key3": "something different", "key4": "completely different"}(ansible-test) ubuntu@ubuntu-xenial:~/ansible$ 
> (ansible-test) ubuntu@ubuntu-xenial:~/ansible$ 
> (ansible-test) ubuntu@ubuntu-xenial:~/ansible$ ansible-playbook -i localhost, playbook.yaml 
> 
> PLAY \[localhost\] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
> 
> TASK \[copy\] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
> changed: \[localhost\]
> 
> PLAY RECAP \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
> localhost : ok=1 changed=1 unreachable=0 failed=0   
> 
> (ansible-test) ubuntu@ubuntu-xenial:~/ansible$ cat output.txt 
> {"key5": "1.2.3", "key3": "something different", "key4": "completely different", "key1": "a\_value", "key2": "something else"}(ansible-test) ubuntu@ubuntu-xenial:~/ansible$ 
> (ansible-test) ubuntu@ubuntu-xenial:~/ansible$ 
> (ansible-test) ubuntu@ubuntu-xenial:~/ansible$ ansible-playbook -i localhost, playbook.yaml 
> 
> PLAY \[localhost\] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
> 
> TASK \[copy\] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
> changed: \[localhost\]
> 
> PLAY RECAP \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
> localhost : ok=1 changed=1 unreachable=0 failed=0   
> 
> (ansible-test) ubuntu@ubuntu-xenial:~/ansible$ cat output.txt 
> {"key1": "a\_value", "key5": "1.2.3", "key4": "completely different", "key3": "something different", "key2": "something else"}(ansible-test) ubuntu@ubuntu-xenial:~/ansible$ 
> (ansible-test) ubuntu@ubuntu-xenial:~/ansible$ 
> \`\`\`

---

<div class="post-metadata">

**Author:** ![vbotka](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/vbotka/32/359_2.png) [@vbotka](https://forum.ansible.com/u/vbotka)\
**Post date:** [March 7, 2025, 8:26am UTC](https://forum.ansible.com/t/inconsistent-expression-evaluation/40816/3 "2025-03-07T08:26:00Z")

</div>

For the record.

Jinja2 evaluates a substitution in an expression. Ansible `does some magic to try and convert strings that look like Python data structures to Python data structures`. This undocumented behavior of a substitution may cause unpredicted malfunctions. For example, the below task

```yaml
    - debug:
        msg: "{{ s }} {{ s | type_debug }}"
      vars:
        s: '{"foo"},'

```

gives

```yaml
msg: '{"foo"}, AnsibleUnicode'

```

The substitution

```yaml
x: foo

```

and the task

```yaml
    - debug:
        msg: "{{ s }} {{ s | type_debug }}"
      vars:
        x: foo
        s: '{"{{ x }}"},'

```

gives

```yaml
msg: ({'foo'},) tuple

```

* * *

Notes:

1. Module copy vs. module template

- The module [ansible.builtin.copy](https://docs.ansible.com/ansible/latest/collections/ansible/builtin/copy_module.html) implements the described magic

```yaml
    - copy:
        dest: /tmp/test.txt
        content: |
          {"{{ x }}"},
      vars:
        x: foo

```

gives

```bash
shell> cat /tmp/test.txt
({'foo'},)

```

In the option [content](https://docs.ansible.com/ansible/latest/collections/ansible/builtin/copy_module.html#parameter-content), the docs says:

> … if content contains a variable, use the ansible.builtin.template module.

- The module [ansible.builtin.template](https://docs.ansible.com/ansible/latest/collections/ansible/builtin/template_lookup.html) keeps the string

```yaml
shell> cat test.txt.j2 
{"{{ x }}"},

```

```yaml
    - template:
        src: test.txt.j2
        dest: /tmp/test.txt
      vars:
        x: foo

```

gives

```bash
shell> cat /tmp/test.txt
{"foo"},

```

---

<div class="post-metadata">

**Author:** ![vbotka](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/vbotka/32/359_2.png) [@vbotka](https://forum.ansible.com/u/vbotka)\
**Post date:** [March 7, 2025, 9:25am UTC](https://forum.ansible.com/t/inconsistent-expression-evaluation/40816/4 "2025-03-07T09:25:44Z")

</div>

Thank you. I think, this should be documented. In [Manipulating data](https://docs.ansible.com/ansible/latest/playbook_guide/complex_data_manipulation.html) perhaps?

---

<div class="post-metadata">

**Author:** ![utoddl](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/utoddl/32/249_2.png) [@utoddl](https://forum.ansible.com/u/utoddl)\
**Post date:** [March 10, 2025, 12:51am UTC](https://forum.ansible.com/t/inconsistent-expression-evaluation/40816/5 "2025-03-10T00:51:09Z")

</div>

> [@vbotka](#):
>
> In the option [content](https://docs.ansible.com/ansible/latest/collections/ansible/builtin/copy_module.html#parameter-content), the docs says:
> 
> > … if content contains a variable, use the ansible.builtin.template module.

I’ve always been bothered by this admonition. There are plenty of instances where the result of using `content:` containing variables is exactly what’s desired.

It would be better I think to describe the difference and dangers between real templates and sneaking templated text into `content:` values, or at least point to a discussion of same. (Previous messages in this topic would be a good start.) Then the user can make an informed decision.

Not that it’s bad advice. It isn’t. But without further discussion it’s like, “Here be dragons!” on old maps. “Pray, tell us more about these dragons…”

---

<div class="post-metadata">

**Author:** ![vbotka](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/vbotka/32/359_2.png) [@vbotka](https://forum.ansible.com/u/vbotka)\
**Post date:** [March 10, 2025, 8:06am UTC](https://forum.ansible.com/t/inconsistent-expression-evaluation/40816/6 "2025-03-10T08:06:57Z")

</div>

Technically, there is no reason why `copy.content` doesn’t implement the same functionality `template.src` does.

---

<div class="post-metadata">

**Author:** ![felixfontein](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/felixfontein/32/7530_2.png) [@felixfontein](https://forum.ansible.com/u/felixfontein)\
**Post date:** [March 10, 2025, 5:20pm UTC](https://forum.ansible.com/t/inconsistent-expression-evaluation/40816/7 "2025-03-10T17:20:10Z")

</div>

The problem isn’t the copy action, but what ansible does with `content` before passing it to the copy action. With Data Tagging we’re finally a big step closer to getting rid of the need to use the `template` module for some inputs.

You should really try out the Data Tagging preview: [Data Tagging preview and testing](https://forum.ansible.com/t/data-tagging-preview-and-testing/40759)