Initial commit: Go 1.23 release state

test/recover1.go

@@ -0,0 +1,141 @@
+// run
+
+// Copyright 2010 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.
+
+// Test of recover during recursive panics.
+// Here be dragons.
+
+package main
+
+import "runtime"
+
+func main() {
+	test1()
+	test2()
+	test3()
+	test4()
+	test5()
+	test6()
+	test7()
+}
+
+func die() {
+	runtime.Breakpoint()	// can't depend on panic
+}
+
+func mustRecover(x interface{}) {
+	mustNotRecover()	// because it's not a defer call
+	v := recover()
+	if v == nil {
+		println("missing recover")
+		die()	// panic is useless here
+	}
+	if v != x {
+		println("wrong value", v, x)
+		die()
+	}
+	
+	// the value should be gone now regardless
+	v = recover()
+	if v != nil {
+		println("recover didn't recover")
+		die()
+	}
+}
+
+func mustNotRecover() {
+	v := recover()
+	if v != nil {
+		println("spurious recover")
+		die()
+	}
+}
+
+func withoutRecover() {
+	mustNotRecover()	// because it's a sub-call
+}
+
+func test1() {
+	// Easy nested recursive panic.
+	defer mustRecover(1)
+	defer func() {
+		defer mustRecover(2)
+		panic(2)
+	}()
+	panic(1)
+}
+
+func test2() {
+	// Sequential panic.
+	defer mustNotRecover()
+	defer func() {
+		v := recover()
+		if v == nil || v.(int) != 2 {
+			println("wrong value", v, 2)
+			die()
+		}
+		defer mustRecover(3)
+		panic(3)
+	}()
+	panic(2)
+}
+
+func test3() {
+	// Sequential panic - like test2 but less picky.
+	defer mustNotRecover()
+	defer func() {
+		recover()
+		defer mustRecover(3)
+		panic(3)
+	}()
+	panic(2)
+}
+
+func test4() {
+	// Single panic.
+	defer mustNotRecover()
+	defer func() {
+		recover()
+	}()
+	panic(4)
+}
+
+func test5() {
+	// Single panic but recover called via defer
+	defer mustNotRecover()
+	defer func() {
+		defer recover()
+	}()
+	panic(5)
+}
+
+func test6() {
+	// Sequential panic.
+	// Like test3, but changed recover to defer (same change as test4 → test5).
+	defer mustNotRecover()
+	defer func() {
+		defer recover()	// like a normal call from this func; runs because mustRecover stops the panic
+		defer mustRecover(3)
+		panic(3)
+	}()
+	panic(2)
+}
+
+func test7() {
+	// Like test6, but swapped defer order.
+	// The recover in "defer recover()" is now a no-op,
+	// because it runs called from panic, not from the func,
+	// and therefore cannot see the panic of 2.
+	// (Alternately, it cannot see the panic of 2 because
+	// there is an active panic of 3.  And it cannot see the
+	// panic of 3 because it is at the wrong level (too high on the stack).)
+	defer mustRecover(2)
+	defer func() {
+		defer mustRecover(3)
+		defer recover()	// now a no-op, unlike in test6.
+		panic(3)
+	}()
+	panic(2)
+}