feat(taskmill): add hierarchical child tasks with two-phase execution#2
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Parent tasks can spawn children during execution via ChildSpawner. Parents enter a Waiting state until all children finish, then a finalize() phase runs before the parent completes. Configurable fail_fast flag controls whether first child failure cancels siblings. Cancelling a parent cascades to all children. Also fixes a pool self-deadlock in store.complete/fail where the connection was held across maybe_prune(), and changes the default retention policy to MaxCount(10,000).
- Add module-level doc comments (`//!`) to all public and internal modules (backpressure, priority, registry, resource, sampler, sysinfo_monitor, scheduler, dispatch, gate, progress, store, task) - Add a `# Quick start` code example to the crate root (`lib.rs`) - Add doc examples for `PressureSource`, `ResourceSampler`, and `ProgressReporter` - Fix broken intra-doc links by qualifying cross-module references (e.g. `[TaskContext::state](crate::TaskContext::state)`) - Tighten visibility: make `StateMap`, `ChildSpawner`, `SmoothedReader`, and `run_sampler` `pub(crate)` instead of `pub` - Remove `ChildSpawner` and `SmoothedReader` from the public re-exports
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deepjoy
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Mar 14, 2026
## 🤖 New release
* `taskmill`: 0.1.1 -> 0.2.0 (⚠ API breaking changes)
### ⚠ `taskmill` breaking changes
```text
--- failure constructible_struct_adds_field: externally-constructible struct adds field ---
Description:
A pub struct constructible with a struct literal has a new pub field. Existing struct literals must be updated to include the new field.
ref: https://doc.rust-lang.org/reference/expressions/struct-expr.html
impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.46.0/src/lints/constructible_struct_adds_field.ron
Failed in:
field SchedulerSnapshot.waiting_count in /tmp/.tmpcxDyU1/taskmill/src/scheduler/mod.rs:48
field SchedulerSnapshot.waiting_count in /tmp/.tmpcxDyU1/taskmill/src/scheduler/mod.rs:48
field TaskRecord.parent_id in /tmp/.tmpcxDyU1/taskmill/src/task.rs:103
field TaskRecord.fail_fast in /tmp/.tmpcxDyU1/taskmill/src/task.rs:107
field TaskRecord.parent_id in /tmp/.tmpcxDyU1/taskmill/src/task.rs:103
field TaskRecord.fail_fast in /tmp/.tmpcxDyU1/taskmill/src/task.rs:107
field TaskSubmission.parent_id in /tmp/.tmpcxDyU1/taskmill/src/task.rs:229
field TaskSubmission.fail_fast in /tmp/.tmpcxDyU1/taskmill/src/task.rs:234
field TaskSubmission.parent_id in /tmp/.tmpcxDyU1/taskmill/src/task.rs:229
field TaskSubmission.fail_fast in /tmp/.tmpcxDyU1/taskmill/src/task.rs:234
field TaskHistoryRecord.parent_id in /tmp/.tmpcxDyU1/taskmill/src/task.rs:144
field TaskHistoryRecord.fail_fast in /tmp/.tmpcxDyU1/taskmill/src/task.rs:146
field TaskHistoryRecord.parent_id in /tmp/.tmpcxDyU1/taskmill/src/task.rs:144
field TaskHistoryRecord.fail_fast in /tmp/.tmpcxDyU1/taskmill/src/task.rs:146
--- failure enum_no_repr_variant_discriminant_changed: enum variant had its discriminant change value ---
Description:
The enum's variant had its discriminant value change. This breaks downstream code that used its value via a numeric cast like `as isize`.
ref: https://doc.rust-lang.org/reference/items/enumerations.html#assigning-discriminant-values
impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.46.0/src/lints/enum_no_repr_variant_discriminant_changed.ron
Failed in:
variant SchedulerEvent::Paused 6 -> 7 in /tmp/.tmpcxDyU1/taskmill/src/scheduler/mod.rs:116
variant SchedulerEvent::Resumed 7 -> 8 in /tmp/.tmpcxDyU1/taskmill/src/scheduler/mod.rs:118
variant SchedulerEvent::Paused 6 -> 7 in /tmp/.tmpcxDyU1/taskmill/src/scheduler/mod.rs:116
variant SchedulerEvent::Resumed 7 -> 8 in /tmp/.tmpcxDyU1/taskmill/src/scheduler/mod.rs:118
--- failure enum_variant_added: enum variant added on exhaustive enum ---
Description:
A publicly-visible enum without #[non_exhaustive] has a new variant.
ref: https://doc.rust-lang.org/cargo/reference/semver.html#enum-variant-new
impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.46.0/src/lints/enum_variant_added.ron
Failed in:
variant TaskStatus:Waiting in /tmp/.tmpcxDyU1/taskmill/src/task.rs:28
variant TaskStatus:Waiting in /tmp/.tmpcxDyU1/taskmill/src/task.rs:28
variant SchedulerEvent:Waiting in /tmp/.tmpcxDyU1/taskmill/src/scheduler/mod.rs:114
variant SchedulerEvent:Waiting in /tmp/.tmpcxDyU1/taskmill/src/scheduler/mod.rs:114
--- failure function_missing: pub fn removed or renamed ---
Description:
A publicly-visible function cannot be imported by its prior path. A `pub use` may have been removed, or the function itself may have been renamed or removed entirely.
ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.46.0/src/lints/function_missing.ron
Failed in:
function taskmill::resource::sampler::run_sampler, previously in file /tmp/.tmpv1zNi5/taskmill/src/resource/sampler.rs:80
--- failure struct_missing: pub struct removed or renamed ---
Description:
A publicly-visible struct cannot be imported by its prior path. A `pub use` may have been removed, or the struct itself may have been renamed or removed entirely.
ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.46.0/src/lints/struct_missing.ron
Failed in:
struct taskmill::resource::sampler::SmoothedReader, previously in file /tmp/.tmpv1zNi5/taskmill/src/resource/sampler.rs:41
struct taskmill::SmoothedReader, previously in file /tmp/.tmpv1zNi5/taskmill/src/resource/sampler.rs:41
struct taskmill::registry::StateMap, previously in file /tmp/.tmpv1zNi5/taskmill/src/registry.rs:24
struct taskmill::StateMap, previously in file /tmp/.tmpv1zNi5/taskmill/src/registry.rs:24
```
<details><summary><i><b>Changelog</b></i></summary><p>
<blockquote>
## [0.2.0](v0.1.1...v0.2.0)
- 2026-03-14
### Added
- *(taskmill)* add hierarchical child tasks with two-phase execution
([#2](#2))
- initial release (migrated from deepjoy/shoebox)
([#1](#1))
### Other
- Initial commit
</blockquote>
</p></details>
---
This PR was generated with
[release-plz](https://github.com/release-plz/release-plz/).
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
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TaskContext::spawn_child()/spawn_children()during executionexecute()returnsand all children complete, the scheduler calls
finalize()on the parentexecutor (e.g. for assembly work like
CompleteMultipartUpload)Waitingtask status for parents blocked on active childrenfail_fastmode (default): first child failure cancels siblingsand fails the parent immediately. When disabled, the parent waits for all
children before resolving
waitingparents; theirrunningchildren arereset to
pendingand re-trigger finalization on completionexample
StateMap,ChildSpawner,SmoothedReader, andrun_samplerpub(crate)Schema changes
tasksandtask_historytables gainparent_id INTEGERandfail_fast INTEGER NOT NULL DEFAULT 1columnsparent_idfor both tables