[GitHub] [airflow] XD-DENG opened a new pull request #13024: Handle None values properly when CLI output is YAML/JSON format

[GitBox]

XD-DENG opened a new pull request #13024:
URL: https://github.com/apache/airflow/pull/13024


   This PR is to address a _minor_ issue in the nice new feature 
(https://github.com/apache/airflow/pull/12704) supporting YAML/JSON format for 
CLI `list` commands (e.g., list connections, users, etc).
   
   This should NOT affect anything regarding 2.0.0rc1. We can include this in 
something like 2.0.1 or 2.1.
   
   ### Description
   
   If there is any `None` value in the data, it is rendered as string `"None"` 
in the YAML/JSON format. This is incorrect, because `None` value is represented 
as `null` in both YAML and JSON, and only when it's `null` it will be 
recognized as "missing" value. `"None"` in YAML or JSON will be considered as a 
normal string.
   
   With this issue, people may get unexpected behaviour when they try to parse 
the YAML/JSON results.
   
   ### Solution
   
   Don't explicitly convert `None` to string.
   
   ### Sample Code to Reproduce The Issue
   
   ```python
   >>> import yaml
   >>> yaml.safe_load("- name: None")
   [{'name': 'None'}]
   >>> yaml.safe_load("- name: null")
   [{'name': None}]
   ```
   
   ### CLI Output BEFORE This Fix (command `airflow connections list -o 
[json|yaml]`)
   
   <img width="393" alt="Default__-zsh_" 
src="https://user-images.githubusercontent.com/11539188/101954100-d3bad900-3bfb-11eb-9548-a38047b7a2d9.png";>
   <img width="1293" alt="Default__-zsh__and_airflow_–_simple_table_py" 
src="https://user-images.githubusercontent.com/11539188/101954105-d6b5c980-3bfb-11eb-82c2-86df3f244466.png";>
   
   ### CLI Output AFTER This Fix (command `airflow connections list -o 
[json|yaml]`)
   
   <img width="344" alt="Default__-zsh_-2" 
src="https://user-images.githubusercontent.com/11539188/101954146-e46b4f00-3bfb-11eb-9fac-1cc265b284d2.png";>
   <img width="1319" 
alt="Default__-zsh__and_airflow_simple_table_py_at_master_·_apache_airflow" 
src="https://user-images.githubusercontent.com/11539188/101954157-e6351280-3bfb-11eb-9d56-9b6c4d1fb4fc.png";>
   
   
   
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