* test(targets): ship a builder MockTarget testkit and retire the in-crate Target mocks
Adds crates/targets/src/testkit.rs with a builder-style MockTarget implementing Target<E> for every E: PluginEvent, with orthogonal off-by-default knobs: disabled/active override, health delay plus health-started signal plus a drop-guard counter proving a cancelled probe future was dropped, an init failure budget (usize::MAX = always fail) plus blocking init plus an init counter, a close counter/signal/semaphore gate with a runtime block toggle, a save counter plus save failure budget, caller-supplied store and failed-store handles, and a shared final-failure counter. Clones and clone_dyn share all counters, so an observer clone keeps watching a target after it is boxed into a runtime.
The module is gated as #[cfg(any(test, feature = "test-support"))]: in-crate unit tests get it via cfg(test), and downstream test suites opt in through the new off-by-default test-support cargo feature (test-support = [], activating no dependencies).
Migrates the five in-crate duplicate mocks onto it: the plugin.rs registry-factory TestTarget, the runtime/adapter.rs lifecycle TestTarget (init/close/store knobs), the runtime/mod.rs TestTarget plus HealthDropGuard (close gating and health-probe tests), the target/mod.rs MoveTestTarget (folded into the test_support helper constructors used by the NATS JetStream failed-store tests), and the target/mod.rs StoreBackedTarget (the default send_from_store purge test; the mock deliberately does not override send_from_store or handle_terminal_failure). The forced init failure now uses TargetError::Initialization instead of the old adapter mock's Configuration; the adapter derives its redacted failure summary from the target id alone, so the migrated assertions are unchanged.
Leak guard: testkit unit tests assert the crate manifest still declares default = [] and that test-support = [] stays a pure cfg gate, complementing the compile-level cfg gate that keeps the mock out of production builds.
Part of rustfs/backlog#1846 (cluster 3, step 1).
* test(notify,audit): migrate the Target mocks onto the shared testkit
Retires the hand-written Target mocks in crates/notify and crates/audit in favor of rustfs_targets::testkit::MockTarget: notify's notifier.rs TestTarget/DeferredTestTarget/ClosableTestTarget, lifecycle.rs BlockingInitTarget/RetryInitTarget (rebuilt as observed MockTarget templates cloned by their plugin-descriptor factories, sharing the init signal, close counter, and single-failure init budget across generations), runtime_view.rs TestTarget, runtime_facade.rs TestTarget, and audit's pipeline.rs MockTarget, system.rs TestTarget, registry.rs CloseTestTarget, plus TestTarget and FailingTarget in audit/tests/pipeline_layer_test.rs. Removing the two integration-test mocks also removes their respelled PluginEvent bound (E: Send + Sync + 'static + Clone + Serialize + DeserializeOwned), which the plugin-contract rules require to be spelled only via PluginEvent.
lifecycle.rs ReplayTarget stays bespoke on purpose: its generation tags, mpsc observation channels, gated send_raw delivery, and ObservedQueueStore model the replay pipeline itself and would contort a general-purpose mock. The other bespoke mocks named out of scope in PR-3a (ProgrammedTarget, ClassifyingTarget, the ReloadableTargetTls fakes) are likewise untouched.
New testkit knobs, each defaulted off and unit-tested: with_id (rename a clone while keeping the shared counters, for factory templates), with_first_save_gate (the first save notifies entered and waits on release; several mocks may share one pair), with_health_gate (is_active waits on a release handle after notifying health_started), with_delivery_snapshot (fixed snapshot overriding the store-derived default), with_close_failures (close-failure budget, default TargetError::Storage) with with_close_failure_error to shape the variant (audit's registry test pins TargetError::Unknown), and an always-on is_enabled call counter exposed as enabled_call_count (notifier's generation tests count dispatcher selections through it).
Both crates enable the testkit through a dev-dependency on rustfs-targets with the test-support feature; the feature stays out of default and activates no dependencies, so production builds are unchanged.
Part of rustfs/backlog#1846 (cluster 3, step 2).
A failed target construction previously logged only reason=construction_failed and pushed an opaque "target construction failed" summary, discarding the underlying TargetError. Debugging rustfs#5115 showed the log repeated every 5s with no root cause, even though the error carried an actionable egress-policy rejection (RUSTFS_OUTBOUND_ALLOW_ORIGINS hint).
The Err branch now includes the error detail in both the error! log (detail field) and the returned failures summary. The detail is scrubbed against the instance's merged config via the loader's existing per-field redaction (secrets -> ***redacted***, endpoint URLs -> origin only, DSNs -> password masked) so credential-bearing values never reach logs or Admin-visible summaries.
A single instance with a malformed `enable` value (e.g. the typo `enable`
instead of `enabled`/`on`) made every configured notification/audit target
of every type fail to load. `create_targets_from_config_with_store_mode`
collected instance configs through the strict `try_collect_target_configs`,
whose `.collect::<Result<Vec, _>>()` short-circuits on the first error and
drops all siblings; the surrounding `?` then aborted the loop over every
plugin type.
This contradicted the function's own documented contract ("Creation is
fault-isolated per instance") and was inconsistent: target construction
failures were already isolated into the `failures` accumulator, only config
collection failures were fatal.
Add `collect_target_config_results[_from_env]`, which returns the enabled
`(id, config)` pairs plus a per-instance failure summary, and use it in the
create path. Per-instance collection errors now flow into the same
`failures`/`creation_failures` accumulator as construction failures: healthy
siblings and other target types still load, while the malformed instance is
surfaced so the notify lifecycle stays non-converged/retryable and an Admin
write cannot report a false success. Audit likewise keeps logging through
its valid targets instead of going fully Stopped.
Follow-up to #5088.
Zhengchao An