Re: [PR] Render Grid and Graph when a path leaves and re-enters a TaskGroup [airflow]

["fat-catTW (via GitHub)" <gi...@apache.org>]

fat-catTW commented on PR #73933:
URL: https://github.com/apache/airflow/pull/73933#issuecomment-5933345574

   Thanks for working on this. 
   But I’m concerned that the current fallback may produce a misleading order beyond just breaking one edge in the group-level cycle.
   
   In the new test case:
   
   ```python
   extract >> staging >> spark_job >> mart >> publish
   ```
   
   the real task path is:
   
   ```text
   extract -> models.staging -> spark_job -> models.mart -> publish
   ```
   
   But the expected root-level order is:
   
   ```text
   extract, models, publish, spark_job
   ```
   
   That puts `publish` before `spark_job`, even though every real task path to `publish` goes through `spark_job`.
   
   I understand that once the collapsed/group-level graph has a cycle, no perfect topological order exists. But this seems potentially confusing for users because the UI may suggest that downstream work outside the cycle can happen before a task it actually depends on. More generally, since a collapsed TaskGroup can only appear once, a path like `models.staging -> spark_job -> models.mart` cannot be faithfully represented as `models -> spark_job -> models`, so the fallback can make the group look like a single execution unit before or after `spark_job`, even though only part of the group is before it.
   
   Is this tradeoff intentional? 


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