--write mode creates problematic yaml output with list-of-lists

[MarkusTeufelberger]

Summary

Running ansible-lint --write on https://github.com/ansible-collections/collection_template rewrites some files (sadly expected) but creates additional yaml[hyphens]: Too many spaces after hyphen errors along the way (unexpected).

Issue Type

• Bug Report

OS / ENVIRONMENT

ansible-lint --version
WARNING: PATH altered to include /home/__removed___/.local/pipx/venvs/ansible-lint/bin :: This is usually a sign of broken local setup, which can cause unexpected behaviors.
ansible-lint 6.14.3 using ansible 2.14.1

• ansible installation method: pipx
• ansible-lint installation method: pipx

STEPS TO REPRODUCE

git clone https://github.com/ansible-collections/collection_template collection_template
cd collection_template
ansible-lint --write
# some errors/warnings...
ansible-lint --write
# different errors/warnings, including new yaml ones

Desired Behavior

Do not introduce additional issues after --write

Actual Behavior

sections:
- - major_changes
  - Major Changes
- - minor_changes
  - Minor Changes
- - breaking_changes
  - Breaking Changes / Porting Guide
- - deprecated_features
  - Deprecated Features
- - removed_features
  - Removed Features (previously deprecated)
- - security_fixes
  - Security Fixes
- - bugfixes
  - Bugfixes
- - known_issues
  - Known Issues

gets rewritten to:

sections:
  -   - major_changes
      - Major Changes
  -   - minor_changes
      - Minor Changes
  -   - breaking_changes
      - Breaking Changes / Porting Guide
  -   - deprecated_features
      - Deprecated Features
  -   - removed_features
      - Removed Features (previously deprecated)
  -   - security_fixes
      - Security Fixes
  -   - bugfixes
      - Bugfixes
  -   - known_issues
      - Known Issues

this apparently looks even worse than before to yamllint

A correct version could be:

sections:
  -
    - major_changes
    - Major Changes
  -
    - minor_changes
    - Minor Changes
  -
    - breaking_changes
    - Breaking Changes / Porting Guide
  -
    - deprecated_features
    - Deprecated Features
  -
    - removed_features
    - Removed Features (previously deprecated)
  -
    - security_fixes
    - Security Fixes
  -
    - bugfixes
    - Bugfixes
  -
    - known_issues
    - Known Issues

[klaus-tux]

I had a look into this and found the following:
Setting self.compact_seq_seq to False in FormattedYAML produces the extra linebreaks, but the nested sequences are indented too far:

sections:
  -
      - major_changes
      - Major Changes
  -
      - minor_changes
      - Minor Changes
...

Unfortunately, I did not find out how to fix the indentation of the inner sequences without screwing up the indentation of all other sequences.

[trishnaguha]

This is assigned to @Qalthos now.