// Copyright 2024 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package yield
import (
"bufio"
"io"
)
//
//
// Modify this block of comment lines as needed when changing imports
// to avoid perturbing subsequent line numbers (and thus error messages).
//
// This is L16.
func goodIter(yield func(int) bool) {
_ = yield(1) && yield(2) && yield(3) // ok
}
func badIterOR(yield func(int) bool) {
_ = yield(1) || // want `yield may be called again \(on L25\) after returning false`
yield(2) || // want `yield may be called again \(on L26\) after returning false`
yield(3)
}
func badIterSeq(yield func(int) bool) {
yield(1) // want `yield may be called again \(on L31\) after returning false`
yield(2) // want `yield may be called again \(on L32\) after returning false`
yield(3) // ok
}
func badIterLoop(yield func(int) bool) {
for {
yield(1) // want `yield may be called again after returning false`
}
}
func goodIterLoop(yield func(int) bool) {
for {
if !yield(1) {
break
}
}
}
func badIterIf(yield func(int) bool) {
ok := yield(1) // want `yield may be called again \(on L52\) after returning false`
if !ok {
yield(2)
} else {
yield(3)
}
}
func singletonIter(yield func(int) bool) {
yield(1) // ok
}
func twoArgumentYield(yield func(int, int) bool) {
_ = yield(1, 1) || // want `yield may be called again \(on L64\) after returning false`
yield(2, 2)
}
func zeroArgumentYield(yield func() bool) {
_ = yield() || // want `yield may be called again \(on L69\) after returning false`
yield()
}
func tricky(in io.ReadCloser) func(yield func(string, error) bool) {
return func(yield func(string, error) bool) {
scan := bufio.NewScanner(in)
for scan.Scan() {
if !yield(scan.Text(), nil) { // want `yield may be called again \(on L82\) after returning false`
_ = in.Close()
break
}
}
if err := scan.Err(); err != nil {
yield("", err)
}
}
}
// Regression test for issue #70598.
func shortCircuitAND(yield func(int) bool) {
ok := yield(1)
ok = ok && yield(2)
ok = ok && yield(3)
ok = ok && yield(4)
}
// This example has a bug because a false yield(2) may be followed by yield(3).
func tricky2(yield func(int) bool) {
cleanup := func() {}
ok := yield(1) // want "yield may be called again .on L104"
stop := !ok || yield(2) // want "yield may be called again .on L104"
if stop {
cleanup()
} else {
// dominated by !stop => !(!ok || yield(2)) => yield(1) && !yield(2): bad.
yield(3)
}
}
// This example is sound, but the analyzer reports a false positive.
// TODO(adonovan): prune infeasible paths more carefully.
func tricky3(yield func(int) bool) {
cleanup := func() {}
ok := yield(1) // want "yield may be called again .on L118"
stop := !ok || !yield(2) // want "yield may be called again .on L118"
if stop {
cleanup()
} else {
// dominated by !stop => !(!ok || !yield(2)) => yield(1) && yield(2): good.
yield(3)
}
}
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