mirror of
https://github.com/golang/go
synced 2024-10-02 16:28:34 -06:00
247 lines
4.5 KiB
Go
247 lines
4.5 KiB
Go
// $G $D/$F.go && $L $F.$A && ./$A.out
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// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Test of basic recover functionality.
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package main
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import "runtime"
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func main() {
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test1()
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test1WithClosures()
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test2()
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test3()
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test4()
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test5()
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test6()
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test6WithClosures()
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test7()
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}
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func die() {
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runtime.Breakpoint() // can't depend on panic
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}
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func mustRecover(x interface{}) {
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mustNotRecover() // because it's not a defer call
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v := recover()
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if v == nil {
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println("missing recover")
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die() // panic is useless here
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}
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if v != x {
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println("wrong value", v, x)
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die()
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}
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// the value should be gone now regardless
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v = recover()
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if v != nil {
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println("recover didn't recover")
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die()
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}
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}
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func mustNotRecover() {
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v := recover()
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if v != nil {
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println("spurious recover", v)
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die()
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}
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}
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func withoutRecover() {
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mustNotRecover() // because it's a sub-call
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}
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func test1() {
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defer mustNotRecover() // because mustRecover will squelch it
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defer mustRecover(1) // because of panic below
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defer withoutRecover() // should be no-op, leaving for mustRecover to find
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panic(1)
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}
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// Repeat test1 with closures instead of standard function.
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// Interesting because recover bases its decision
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// on the frame pointer of its caller, and a closure's
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// frame pointer is in the middle of its actual arguments
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// (after the hidden ones for the closed-over variables).
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func test1WithClosures() {
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defer func() {
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v := recover()
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if v != nil {
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println("spurious recover in closure")
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die()
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}
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}()
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defer func(x interface{}) {
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mustNotRecover()
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v := recover()
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if v == nil {
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println("missing recover")
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die()
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}
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if v != x {
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println("wrong value", v, x)
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die()
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}
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}(1)
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defer func() {
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mustNotRecover()
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}()
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panic(1)
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}
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func test2() {
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// Recover only sees the panic argument
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// if it is called from a deferred call.
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// It does not see the panic when called from a call within a deferred call (too late)
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// nor does it see the panic when it *is* the deferred call (too early).
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defer mustRecover(2)
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defer recover() // should be no-op
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panic(2)
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}
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func test3() {
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defer mustNotRecover()
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defer func() {
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recover() // should squelch
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}()
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panic(3)
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}
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func test4() {
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// Equivalent to test3 but using defer to make the call.
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defer mustNotRecover()
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defer func() {
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defer recover() // should squelch
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}()
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panic(4)
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}
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// Check that closures can set output arguments.
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// Run g(). If it panics, return x; else return deflt.
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func try(g func(), deflt interface{}) (x interface{}) {
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defer func() {
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if v := recover(); v != nil {
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x = v
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}
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}()
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defer g()
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return deflt
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}
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// Check that closures can set output arguments.
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// Run g(). If it panics, return x; else return deflt.
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func try1(g func(), deflt interface{}) (x interface{}) {
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defer func() {
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if v := recover(); v != nil {
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x = v
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}
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}()
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defer g()
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x = deflt
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return
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}
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func test5() {
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v := try(func() { panic(5) }, 55).(int)
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if v != 5 {
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println("wrong value", v, 5)
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die()
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}
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s := try(func() {}, "hi").(string)
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if s != "hi" {
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println("wrong value", s, "hi")
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die()
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}
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v = try1(func() { panic(5) }, 55).(int)
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if v != 5 {
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println("try1 wrong value", v, 5)
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die()
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}
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s = try1(func() {}, "hi").(string)
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if s != "hi" {
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println("try1 wrong value", s, "hi")
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die()
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}
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}
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// When a deferred big call starts, it must first
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// create yet another stack segment to hold the
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// giant frame for x. Make sure that doesn't
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// confuse recover.
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func big(mustRecover bool) {
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var x [100000]int
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x[0] = 1
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x[99999] = 1
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_ = x
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v := recover()
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if mustRecover {
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if v == nil {
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println("missing big recover")
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die()
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}
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} else {
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if v != nil {
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println("spurious big recover")
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die()
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}
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}
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}
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func test6() {
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defer big(false)
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defer big(true)
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panic(6)
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}
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func test6WithClosures() {
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defer func() {
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var x [100000]int
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x[0] = 1
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x[99999] = 1
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_ = x
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if recover() != nil {
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println("spurious big closure recover")
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die()
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}
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}()
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defer func() {
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var x [100000]int
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x[0] = 1
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x[99999] = 1
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_ = x
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if recover() == nil {
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println("missing big closure recover")
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die()
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}
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}()
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panic("6WithClosures")
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}
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func test7() {
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ok := false
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func() {
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// should panic, then call mustRecover 7, which stops the panic.
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// then should keep processing ordinary defers earlier than that one
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// before returning.
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// this test checks that the defer func on the next line actually runs.
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defer func() { ok = true }()
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defer mustRecover(7)
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panic(7)
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}()
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if !ok {
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println("did not run ok func")
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die()
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}
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}
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