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Merge pull request #5402 from Luv-Ray/short-circuit

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`expr`: short-circuit evaluation for `&`
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Daniel Hofstetter 2023-10-14 07:50:47 +02:00 • committed by GitHub
commit 21c8538e0b
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2 changed files with 34 additions and 9 deletions
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28
src/uu/expr/src/syntax_tree.rs
View file

@ -166,16 +166,26 @@ impl AstNode {
{
let mut out = Vec::with_capacity(operands.len());
let mut operands = operands.iter();
// check the first value before `|`, stop evaluate and return directly if it is true.
// push dummy to pass the check of `len() == 2`
if op_type == "|" {
if let Some(value) = operands.next() {
let value = value.evaluate()?;
out.push(value.clone());
if value_as_bool(&value) {
out.push(String::from("dummy"));
return Ok(out);
if let Some(value) = operands.next() {
let value = value.evaluate()?;
out.push(value.clone());
// short-circuit evaluation for `|` and `&`
// push dummy to pass `assert!(values.len() == 2);`
match op_type.as_ref() {
"|" => {
if value_as_bool(&value) {
out.push(String::from("dummy"));
return Ok(out);
}
}
"&" => {
if !value_as_bool(&value) {
out.push(String::from("dummy"));
return Ok(out);
}
}
_ => {}
}
}

15
tests/by-util/test_expr.rs
View file

@ -155,6 +155,21 @@ fn test_and() {
.args(&["-14", "&", "1"])
.run()
.stdout_is("-14\n");
new_ucmd!()
.args(&["0", "&", "a", "/", "5"])
.run()
.stdout_only("0\n");
new_ucmd!()
.args(&["", "&", "a", "/", "5"])
.run()
.stdout_only("0\n");
new_ucmd!()
.args(&["-1", "&", "10", "/", "5"])
.succeeds()
.stdout_only("-1\n");
}
#[test]