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

`expr`: short-circuit evaluation for `&`

src/uu/expr/src/syntax_tree.rs

@@ -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);
+ }
  }
+ _ => {}
  }
  }
 

tests/by-util/test_expr.rs

@@ -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]