Closed
Description
@neelance, I took the first failing test of #495 and looked into it. I was able to reproduce it and narrow it down to the following bug, which existed in 1.6 too, but archive/tar internals changed to start doing this pattern (and they weren't in 1.6).
--- FAIL: TestReader (0.02s)
/home/ubuntu/gopherjs/test.618412033:4
Error.stackTraceLimit=Infinity;var $global,$module;if(typeof window!=="undefined"){$global=window;}else if(typeof self!=="undefined"){$global=self;}else if(typeof global!=="undefined"){$global=global;$global.require=require;}else{$global=this;}if($global===undefined||$global.Array===undefined){throw new Error("no global object found");}if(typeof module!=="undefined"){$module=module;}var $packages={},$idCounter=0;var $keys=function(m){return m?Object.keys(m):[];};var $flushConsole=function(){};var $throwRuntimeError;var $throwNilPointerError=function(){$throwRuntimeError("invalid memory address or nil pointer dereference");};var $call=function(fn,rcvr,args){return fn.apply(rcvr,args);};var $makeFunc=function(fn){return function(){return $externalize(fn(this,new($sliceType($jsObjectPtr))($global.Array.prototype.slice.call(arguments,[]))),$emptyInterface);};};var $mapArray=function(array,f){var newArray=new array.constructor(array.length);for(var i=0;i<array.length;i++){n
Error: runtime error: slice bounds out of range
at $callDeferred (/home/ubuntu/gopherjs/test.618412033:4:28652)
at $panic (/home/ubuntu/gopherjs/test.618412033:4:29276)
at $b (/home/ubuntu/gopherjs/test.618412033:36:64240)
at $callDeferred (/home/ubuntu/gopherjs/test.618412033:4:28823)
at $panic (/home/ubuntu/gopherjs/test.618412033:4:29276)
at $throwRuntimeError (/home/ubuntu/gopherjs/test.618412033:7:3303)
at $subslice (/home/ubuntu/gopherjs/test.618412033:4:2011)
at $packages.archive/tar.AA.Chksum (/home/ubuntu/gopherjs/test.618412033:39:21828)
at $packages.archive/tar.$ptrType.Chksum (/home/ubuntu/gopherjs/test.618412033:39:21939)
at $packages.archive/tar.Z.GetFormat (/home/ubuntu/gopherjs/test.618412033:39:18410)
at $packages.archive/tar.$ptrType.GetFormat (/home/ubuntu/gopherjs/test.618412033:39:19262)
at $packages.archive/tar.AG.ptr.readHeader (/home/ubuntu/gopherjs/test.618412033:39:44422)
at $packages.archive/tar.AG.ptr.Next (/home/ubuntu/gopherjs/test.618412033:39:30084)
at $packages.archive/tar.BL (/home/ubuntu/gopherjs/test.618412033:39:79511)
at $packages.testing.CA (/home/ubuntu/gopherjs/test.618412033:36:65548)
at $goroutine (/home/ubuntu/gopherjs/test.618412033:4:29874)
at Timeout.$runScheduled [as _onTimeout] (/home/ubuntu/gopherjs/test.618412033:4:30643)
at tryOnTimeout (timers.js:224:11)
at Timer.listOnTimeout (timers.js:198:5)
FAIL archive/tar 0.427s
The problem appears to be when you have an array, and you take its address, then convert the pointer to another type, and try to access the slice.
package main
import "fmt"
const blockSize = 512
type block [blockSize]byte
type headerV7 [blockSize]byte
func main() {
var x block
y := (*headerV7)(&x)
fmt.Println(y[148:][:8])
}https://play.golang.org/p/k21kDwVgbB
http://www.gopherjs.org/playground/#/pKu10Nu76j