# Upgrading processkit
Per-version notes for **consumers** moving their dependency forward: what breaks,
who it affects, and the exact change to make. The [CHANGELOG](../CHANGELOG.md) is
the full record; this page is the "I depend on it, what do I do" view.
> **Pre-1.0 versioning.** Under Cargo's semver rules a `0.x` crate treats the
> *minor* as the breaking position, so a `0.10 → 0.11` bump can carry breaking
> changes. Pin to a minor range — `processkit = "0.11"` allows `0.11.*` but not
> `0.12` — and skim the relevant section here before each minor bump.
## 0.11.0 (from 0.10.x)
Two breaking changes, both small and **caught by the compiler** — if it builds
after the bump, you're done. Plus one internal fix that needs no action.
### 1. `stats` is now opt-in — a `Cargo.toml` change
The default feature set is now just `process-control`; `stats` is no longer on by
default. (It is the one feature carrying an extra build dependency — the Windows
`ProcessStatus` FFI used solely for the peak-memory readout — and it gates a
specialized metrics surface the core never needs.)
**Affected if you use any metrics API:** `ProcessGroup::stats` /
`ProcessGroupStats`, `RunningProcess::cpu_time` / `peak_memory_bytes`, or
`RunProfile` / `RunningProcess::profile`. The symptom is a build error like
*"no method named `stats` / `cpu_time` / `peak_memory_bytes` / `profile`"* or
*"cannot find type `ProcessGroupStats` / `RunProfile`"*.
**Fix** — add the feature:
```toml
[dependencies]
processkit = { version = "0.11", features = ["stats"] }
```
If you already enable `limits`, do **nothing** — `limits` still implies `stats`.
**If you don't use metrics:** nothing to do. Your default build is now slightly
leaner (no Windows `ProcessStatus` dependency).
### 2. `OutputEvent` carries `OutputLine` — a code change
Affects only callers of `RunningProcess::output_events` (the ordered
lifecycle+output event stream). The per-line payload changed from a bare `String`
to a `#[non_exhaustive]` `OutputLine` struct with a public `text` field.
Before:
```rust
use processkit::OutputEvent;
while let Some(ev) = events.next().await {
match ev {
OutputEvent::Stdout(s) => println!("out: {s}"),
OutputEvent::Stderr(s) => eprintln!("err: {s}"),
_ => {}
}
}
```
After — read `line.text`:
```rust
match ev {
OutputEvent::Stdout(line) => println!("out: {}", line.text),
OutputEvent::Stderr(line) => eprintln!("err: {}", line.text),
_ => {}
}
```
Or, when you don't care which stream produced the line, use the new accessor:
```rust
if let Some(text) = ev.text() {
println!("{text}");
}
```
`OutputLine` is `#[non_exhaustive]`: you receive it from the crate and read its
fields — you don't construct it, and a `match` on it should use `..`. The change
exists to reserve room for per-line metadata (e.g. a timestamp or a monotonic line
index) in a later release without another break.
### 3. Cancel-precedence fix ("Issue 7") — no action
A run that reaps on its own is no longer at risk of being misreported as
`Err(Cancelled)` by a cancellation token that fires in the narrow window between
the reap and the disposition check. This is an internal correctness fix with no
public-API change. If you carried a workaround that tolerated a spurious
`Cancelled` on a self-completing run, you can remove it.
### Verify the upgrade
```sh
cargo update -p processkit
cargo build # both breaking changes are compiler-caught
cargo test
```
## Upgrading from older than 0.10
The jumps below 0.10 predate this guide. Read the dated sections of the
[CHANGELOG](../CHANGELOG.md) for each minor you cross — every breaking entry there
is marked **Breaking** and carries its own migration note. Notable recent
non-breaking additions you gain along the way: `Command::checked` / `run_unit`
(0.10.2) and the `record`-cassette symlink/`Display`-injection hardening (0.10.2).