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empty-catches

Same as empty_catches in Dart lints

Group: Suspicious
Path: lint/suspicious/empty-catches
Default: On (recommended)
Origin: Dart lints
Rule: 229 of 512

recommended

Flags empty catch blocks.

A catch clause with no body silently swallows the exception, hiding failures that should be handled, logged, or rethrown and making bugs far harder to diagnose. Handle the error, or at minimum log it, rather than discarding it. Two escape hatches match the official lint: a catch whose body contains a comment (the emptiness is deliberate and documented), and a catch that binds its exception to _, an explicit "I am ignoring this" marker.

This includes catch clauses inside anonymous functions.

Invalid

example.dartdart

void f1() {
  try {
    doThing();
  } catch (e) {}
}

void f2() {
  try {
    doThing();
  } on Exception catch (e) {}
}

void f3() {
  try {
    doThing();
  } catch (e, st) {}
}

void f4() {
  try {
    doThing();
  } on StateError {}
}

void f5() {
  try {
    doThing();
  } catch (error) {}
}

void f6() {
  try {
    doThing();
  } catch (e) {
  }
}

Handle the exception, add a comment, or name it `_` instead of leaving this catch block empty.

3 doThing();

4 } catch (e) {}

∙

Handle the exception, add a comment, or name it `_` instead of leaving this catch block empty.

9 doThing();

10 } on Exception catch (e) {}

∙

Handle the exception, add a comment, or name it `_` instead of leaving this catch block empty.

15 doThing();

16 } catch (e, st) {}

∙

Handle the exception, add a comment, or name it `_` instead of leaving this catch block empty.

21 doThing();

22 } on StateError {}

∙

Handle the exception, add a comment, or name it `_` instead of leaving this catch block empty.

27 doThing();

28 } catch (error) {}

∙

Handle the exception, add a comment, or name it `_` instead of leaving this catch block empty.

34 } catch (e) {

35 }

∙

Valid

example.dartdart

void g1() {
  try {
    doThing();
  } catch (e) {
    print(e);
  }
}

void g2() {
  try {
    doThing();
  } catch (_) {}
}

void g3() {
  try {
    doThing();
  } catch (e) {
    // Failure is expected and intentionally ignored here.
  }
}

void g4() {
  try {
    doThing();
  } on Exception catch (e) {
    handle(e);
  }
}

void g5() {
  try {
    doThing();
  } on StateError catch (_) {}
}

void g6() {
  try {
    doThing();
  } catch (e, st) {
    print('$e $st');
  }
}

String documentedInterpolation() => '${(() {
  try {
    doThing();
  } catch (error) { /* Deliberately ignore this } and { failure. */ }
  return '';
})()}';

Configure empty-catches

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

falcon.jsonjson

{
  "linter": {
    "rules": {
      "suspicious": {
        "empty-catches": "error"
      }
    }
  }
}

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

example.dartdart

// falcon-ignore lint/suspicious/empty-catches: <reason>

empty-statementsempty_statementsrecommended
Flags stray empty statements (a lone ;).
no-duplicate-case-valuesno_duplicate_case_valuesrecommended
Flags semantically equal constant values within one switch.
no-empty-blockno-empty-block
Flags empty blocks ({}).
no-equal-argumentsno-equal-arguments
Flags an argument passed more than once in the same invocation.
no-equal-then-elseno-equal-then-elserecommended
Flags an if/else or ternary whose two branches are identical.
no-magic-string
Extract inline string literals into named variables or constants.
no-self-comparisonsno_self_comparisonsrecommended
Flags proven self-comparisons of side-effect-free scalar values.
no-wildcard-variable-usesno_wildcard_variable_usesrecommended
Flags references to a wildcard variable or parameter (a name made solely of underscores, such as _ or __).