cancel_subscriptions

Cancel instances of dart:async StreamSubscription.

DO invoke cancel on instances of dart:async StreamSubscription.

Cancelling instances of StreamSubscription prevents memory leaks and unexpected behavior.

BAD:

class A {  StreamSubscription _subscriptionA; // LINT  void init(Stream stream) {  _subscriptionA = stream.listen((_) {});  } } 

BAD:

void someFunction() {  StreamSubscription _subscriptionF; // LINT } 

GOOD:

class B {  StreamSubscription _subscriptionB; // OK  void init(Stream stream) {  _subscriptionB = stream.listen((_) {});  } ​  void dispose(filename) {  _subscriptionB.cancel();  } } 

GOOD:

void someFunctionOK() {  StreamSubscription _subscriptionB; // OK  _subscriptionB.cancel(); } 

Known limitations

This rule does not track all patterns of StreamSubscription instantiations and cancellations. See linter#317 for more information.

To enable the cancel_subscriptions rule, add cancel_subscriptions under linter > rules in your analysis_options.yaml file:

linter:  rules:  - cancel_subscriptions 

If you're instead using the YAML map syntax to configure linter rules, add cancel_subscriptions: true under linter > rules:

linter:  rules:  cancel_subscriptions: true