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avoid-missing-completer-stack-trace

Group: Correctness
Path: lint/correctness/avoid-missing-completer-stack-trace
Default: Off, opt in
Origin: Falcon
Rule: 84 of 512

Preserve error origins when calling SDK Completer.completeError. Pass the caught stack trace, or StackTrace.current, as the second argument.

Checks ordinary, null-aware, and cascade calls using resolved receiver types. Explicit null is missing too. Custom same-named methods and dynamic receivers are ignored; inherited methods are checked only when their SDK owner resolves and library/import lookup does not select a different completeError function.

Reference: https://dcm.dev/docs/rules/common/avoid-missing-completer-stack-trace/

Invalid

example.dartdart

import 'dart:async';
import 'dart:async' as async;

void errors(Completer<int> completer, Completer<void>? nullable, async.Completer<String> prefixed) {
  completer.completeError('first');
  completer.completeError('second', null);
  nullable?.completeError('third');
  prefixed.completeError('fourth');
  completer..completeError('fifth');
}

Pass a stack trace as the second argument to `Completer.completeError`.

4void errors(Completer<int> completer, Completer<void>? nullable, async.Completer<String> prefixed) {

5 completer.completeError('first');

∙

Pass a stack trace as the second argument to `Completer.completeError`.

5 completer.completeError('first');

6 completer.completeError('second', null);

∙

Pass a stack trace as the second argument to `Completer.completeError`.

6 completer.completeError('second', null);

7 nullable?.completeError('third');

∙

Pass a stack trace as the second argument to `Completer.completeError`.

7 nullable?.completeError('third');

8 prefixed.completeError('fourth');

∙

Pass a stack trace as the second argument to `Completer.completeError`.

8 prefixed.completeError('fourth');

9 completer..completeError('fifth');

∙

Valid

example.dartdart

import 'dart:async';

class Custom {
  void completeError(Object error) {}
}

void errors(Completer<int> completer, Completer<void>? nullable, dynamic unknown, StackTrace trace) {
  completer.completeError('first', trace);
  completer.completeError('second', StackTrace.current);
  nullable?.completeError('third', trace);
  completer..completeError('fourth', trace);
  Custom().completeError('custom');
  unknown.completeError('unknown');
  completer.complete(1);
}

abstract class Overriding<T> implements Completer<T> {
  void completeError(Object error, [StackTrace? stackTrace]) {}
  void fail(Object error) {
    completeError(error);
  }
}

extension CustomCompleterErrors<T> on Completer<T> {
  void completeError(Object error) {}
  void failWithCustomHandler(Object error) {
    completeError(error);
  }
}

Configure avoid-missing-completer-stack-trace

Set its severity in falcon.json. See the configuration guide.

falcon.jsonjson

{
  "linter": {
    "rules": {
      "correctness": {
        "avoid-missing-completer-stack-trace": "error"
      }
    }
  }
}

Or silence one occurrence with a suppression comment; the reason is required.

example.dartdart

// falcon-ignore lint/correctness/avoid-missing-completer-stack-trace: <reason>

avoid-missing-controllerflutter
Require Flutter text fields to expose their updated value.
avoid-missing-enum-constant-in-map
Require enum-keyed map literals to include every declared enum value.
avoid-missing-interpolationrecommended
Flags missing interpolation around visible String variables or member accesses and calls.
avoid-misused-hooksrecommendedflutter_hooks
Flags confirmed Flutter hooks called directly in non-hook Flutter widget builds.
avoid-mounted-in-setstateflutter
Check mounted before invoking Flutter State.setState, never inside its callback.
avoid-mutable-equatable-subclass-fieldsrecommendedequatable
Flags mutable instance fields on subclasses inheriting Equatable equality.
avoid-mutable-global-variablesavoid_mutable_global_variables
Disallow mutable top-level variables.
avoid-nested-futures
Avoid Future<Future<T>>, FutureOr<Future<T>>, and other directly nested future wrappers.