invariant_booleans
Conditions should not unconditionally evaluate to true
or to false
.
This rule has been removed as of the latest Dart releases.
Details
#NOTE: This rule is removed in Dart 3.0.0; it is no longer functional.
DON'T test for conditions that can be inferred at compile time or test the same condition twice.
Conditional statements using a condition which cannot be anything but false
have the effect of making blocks of code non-functional. If the condition
cannot evaluate to anything but true
, the conditional statement is completely
redundant, and makes the code less readable.
It is quite likely that the code does not match the programmer's intent.
Either the condition should be removed or it should be updated so that it does
not always evaluate to true
or false
and does not perform redundant tests.
This rule will hint to the test conflicting with the linted one.
BAD:
// foo can't be both equal and not equal to bar in the same expression
if(foo == bar && something && foo != bar) {...}
BAD:
void compute(int foo) {
if (foo == 4) {
doSomething();
// we know foo is equal to 4 at this point, so the next condition is always false
if (foo > 4) {...}
...
}
...
}
BAD:
void compute(bool foo) {
if (foo) {
return;
}
doSomething();
// foo is always false here
if (foo){...}
...
}
GOOD:
void nestedOK() {
if (foo == bar) {
foo = baz;
if (foo != bar) {...}
}
}
GOOD:
void nestedOk2() {
if (foo == bar) {
return;
}
foo = baz;
if (foo == bar) {...} // OK
}
GOOD:
void nestedOk5() {
if (foo != null) {
if (bar != null) {
return;
}
}
if (bar != null) {...} // OK
}
Usage
#To enable the invariant_booleans
rule,
add invariant_booleans
under linter > rules in your
analysis_options.yaml
file:
linter:
rules:
- invariant_booleans
除非另有说明,文档之所提及适用于 Dart 3.5.3 版本,本页面最后更新时间: 2024-08-02。 查看文档源码 或者 报告页面问题。