fix: make derived notifiers detach on last listener removals - #2
Feichtmeier wants to merge 2 commits into
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- Behavior change (fixes a listener leak): derived notifiers created by the
operators (`select`, `map`, `where`, `debounce`, `async`, `combineLatest*`,
`mergeWith`) now **detach from their source when their last listener is
removed**, symmetric to how they attach on the first listener. Previously a
chain stayed subscribed to its source forever (until `dispose()`), which
leaked a listener on the source every time an operator chain was created
inline and discarded (e.g. inside a `build()` / `watchValue`).
- On re-observation a chain **resyncs** its value from the current source
value, so resubscription remains correct and never stale.
- The only observable difference: while a chain has **zero** listeners it no
longer tracks its source (its `.value` is refreshed on the next
observation instead of continuously). Chains that always have at least one
listener are unaffected.
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…e on read Chains now remove their handler from the source when their last listener is removed and re-attach (with resync) on the next one. While detached, .value is derived from the current source value so it never goes stale (the functional_listener escamoteur#13 scenario). Fixes listener accumulation on long-lived sources when chains are created per widget instance. Based on #2 by @Feichtmeier. Also fixes AsyncValueNotifier writing into a disposed notifier, deduplicates the combining notifiers, updates README/docs/skill, removes cross-package skill copies and stops committing pubspec.lock.
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Thank you — this was a real problem (one dead chain per widget instance accumulating on long-lived sources) and your detach mechanism is the core of what ships in 6.0.0. We couldn't take the PR as-is, though: detach-on-last-listener is exactly what functional_listener had until v4.0.0, where it was removed because |
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thank you! |
2 participants
select,map,where,debounce,async,combineLatest*,mergeWith) now detach from their source when their last listener is removed, symmetric to how they attach on the first listener. Previously a chain stayed subscribed to its source forever (untildispose()), which leaked a listener on the source every time an operator chain was created inline and discarded (e.g. inside abuild()/watchValue)..valueis refreshed on the next observation instead of continuously). Chains that always have at least one listener are unaffected.