#4900 has gone beyond a basic sed file and is now the basis for a more generic linter 🎉.

Some follow-on ideas:

Editor integration:

(See #5014)

7 to 8 migration rules

This linter could be a highly valuable tool in the 7->8 upgrade. Also include a couple of Python 2->3 pointers.

• Missing shebang
  • If Jinja2 or EmPy syntax is detected in the suite.rc or flow.cylc file and the first line of the file is not a matching shebang.
  • (rose suite-run used to tolerate missing shebang lines)
• Module name changes
  • cylc -> cylc.flow
  • rose -> metomi.rose
  • isodatetime -> metomi.isodatetime
  • In Python files from _ import and import _.
  • In .cylc & .rc files from "_" import
• Tabs in Python files (e.g. Jinja2 filters)
  • Use spaces to indent Python 3 files, mix of tabs and spaces is a syntax error.
• Zero-prefixed integers in .cylc, .rc files.
  • E.G. 05 rather than 5, previously accepted, now a Jinja2 syntax error.
• Suicide triggers
  • No longer needed, use optional outputs (for .cylc files only).
• platform = $(rose host-select)
  • Advise using built-in host selection via configured platforms rather than $(rose host-select).
  • Note there may be legit reasons to use subshells here (platforms does not offer a filter interface yet).
  • But rose host-select is definitely unnecessary.
• Deprecated env vars (all files in project).
• Check for deprecated commands (documented in cylc.flow.scripts.cylc.DEAD_ENDS).
• Parameter simplification
  • <x><y> is valid but can be simplified <x, y>
  • See Support expanding <param1><param2> in inherited family names #5537
• Deprecated task and workflow event template variables
  • e.g. %(suite) = Feat.lint obsolete vars #5879
• Use of rose suite-hook (command removed at Rose 2)
• CYLC_VERSION={{CYLC_VERSION}} (same for ROSE_ and FCM_). lint: Warn users that CYLC_VERSION={{CYLC_VERSION}} is deprecated #5890
• Using cylc workflow-state in a task-script, should use the workflow_state xtrigger instead
• :expired output must be optional if used (also :expire, :expire-all and :expire-any), see optional output extension proposal.

Additional style rules and bug bears

• ...

Pull requests welcome!