shahar1 opened a new pull request, #75417:
URL: https://github.com/apache/airflow/pull/75417
related: #39801, #69377
<!-- HUMAN SUMMARY - AGENTS DO NOT MODIFY -->
<!-- END OF HUMAN SUMMARY -->
<details><summary>AI Summary</summary>
A task with `trigger_rule="all_done_min_one_success"` inside a dynamically
mapped task group never expands when all of its direct upstreams are in the
same group. Its unexpanded placeholder (`map_index=-1`) is marked
`upstream_failed` and the Dag run fails, even when every upstream instance
succeeds:
```
init[-1] = success
tg.imsleepy[0..2] = success
tg.imawake[-1] = upstream_failed # never expands
```
Reproduced with `airflow dags test` in Breeze on main.
**Cause.** For the placeholder, the relevant map index of an in-group
upstream is `-1`. Once that upstream expands, no upstream task instance has map
index `-1`, so the placeholder counts zero upstreams. `all_success`,
`none_failed` and `all_done` pass on zero upstreams and the task expands.
`all_done_min_one_success` reads zero as "all done, none succeeded" and sets
`upstream_failed`.
**Fix.** When a placeholder inside a mapped task group has no upstream task
instance left to judge, the trigger rule check now passes without setting a
state. The task expands and each expanded instance evaluates its own upstreams,
as with the other "all done" rules.
#69377 fixed the same symptom for `none_failed_min_one_success` by adding it
to `is_fast_triggered`. Doing the same here was rejected: the placeholder would
then count every upstream instance, so one skipped index would skip the whole
task. It would also regress shapes that work on main today, such as a task that
also takes the group's mapped argument.
Per-index results for `all_done_min_one_success`, in-group upstream only:
| Upstream index 1 | main | this PR |
|---|---|---|
| succeeds | `{-1: upstream_failed}` | `{0, 1, 2: success}` |
| skipped | `{-1: upstream_failed}` | `{0: success, 1: skipped, 2: success}`
|
| failed | `{-1: upstream_failed}` | `{0: success, 1: upstream_failed, 2:
success}` |
Shapes where the task also has the mapped argument or an outside task as
upstream already decide per index on main and are unchanged.
A before/after comparison of `dag.test()` runs covered every trigger rule
except `always`, several upstream shapes, skipped/failed upstream indexes,
branching, zero-length expansion and a mapped group inside a loop. Only
`all_done_min_one_success` results changed, and all to per-index states.
Known limitations, not regressions:
- `all_done_min_one_success` with a **failed** upstream outside the group
and a successful one inside still ends `{-1: upstream_failed}`, as on main.
- `none_failed_min_one_success` (#69377) still fails the whole task when one
in-group upstream index fails. Moving it from `is_fast_triggered` to this guard
may fix that; left for a follow-up.
</details>
---
##### Was generative AI tooling used to co-author this PR?
- [X] Yes — Claude Code (Opus 5.5)
Generated-by: Claude Code (Opus 5.5) following [the
guidelines](https://github.com/apache/airflow/blob/main/contributing-docs/05_pull_requests.rst#gen-ai-assisted-contributions)
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