[asterisk-bugs] [JIRA] (ASTERISK-25525) A call EndWhile can cause the dial plan to jump to another context.

[Rusty Newton (JIRA)]

     [ https://issues.asterisk.org/jira/browse/ASTERISK-25525?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Rusty Newton updated ASTERISK-25525:
------------------------------------

    Description: 
[Edit by Rusty - Adding a note here at the top for quick reference. The documentation is not sufficient currently. See Richard's comment]

I would expect that a While/EndWhile loop would be restricted to a single context. However, in some cases a call EndWhile can cause the dial plan to jump to another context. We have noticed this with Gosub and Goto.

Here is a simple example:
{code:title=extensions.conf|borderStyle=solid}
[test-while-out]
exten => s,1,Set(i=0)
 same => n,While($[${INC(i)} <= 5])
  same => n,Log(NOTICE,i is ${i})
  same => n,Gosub(test-while-inner,s,1)
 same => n,EndWhile

[test-while-inner]
exten => s,1,Set(j=0)
 same => n,While($[${INC(j)} <= 5])
  same => n,Log(NOTICE,j is ${j})
  same => n,Return
 same => n,EndWhile
 same => n,Return
{code}

And in the Asterisk console execute:
{code:title=Console|borderStyle=solid}
*CLI> originate Local/s at test-while-out application wait 10
    -- Executing [s at test-while-out:1] Set("Local/s at test-while-out-00000008;2", "i=0") in new stack
    -- Executing [s at test-while-out:2] While("Local/s at test-while-out-00000008;2", "1") in new stack
    -- Executing [s at test-while-out:3] Log("Local/s at test-while-out-00000008;2", "NOTICE,i is 1") in new stack
[2015-11-05 16:28:59] NOTICE[27770][C-00000013]: Ext. s:3 @ test-while-out: i is 1
    -- Executing [s at test-while-out:4] Gosub("Local/s at test-while-out-00000008;2", "test-while-inner,s,1") in new stack
    -- Executing [s at test-while-inner:1] Set("Local/s at test-while-out-00000008;2", "j=0") in new stack
    -- Executing [s at test-while-inner:2] While("Local/s at test-while-out-00000008;2", "1") in new stack
    -- Executing [s at test-while-inner:3] Log("Local/s at test-while-out-00000008;2", "NOTICE,j is 1") in new stack
[2015-11-05 16:28:59] NOTICE[27770][C-00000013]: Ext. s:3 @ test-while-inner: j is 1
    -- Executing [s at test-while-inner:4] Return("Local/s at test-while-out-00000008;2", "") in new stack
    -- Executing [s at test-while-out:5] EndWhile("Local/s at test-while-out-00000008;2", "") in new stack
    -- Executing [s at test-while-inner:2] While("Local/s at test-while-out-00000008;2", "1") in new stack
    -- Executing [s at test-while-inner:3] Log("Local/s at test-while-out-00000008;2", "NOTICE,j is 2") in new stack
[2015-11-05 16:28:59] NOTICE[27770][C-00000013]: Ext. s:3 @ test-while-inner: j is 2
    -- Executing [s at test-while-inner:4] Return("Local/s at test-while-out-00000008;2", "") in new stack
[2015-11-05 16:28:59] ERROR[27770][C-00000013]: app_stack.c:378 return_exec: Return without Gosub: stack is empty
  == Spawn extension (test-while-inner, s, 4) exited non-zero on 'Local/s at test-while-out-00000008;2'
{code}

The call starts at test-while-out which contains a While/EndWhile loop. Inside that loop it logs the value of {{i}} and the Gosubs to test-while-inner. The inner context also contains a While/EndWhile loop but we return from inside the loop. In the real world this would be due to some conditional statement. After returning to the outer loop we call EndWhile. I would expect this to bring us back to the beginning of the outer loop. But it actually brings us back to the beginning of the inner loop.

  was:
I would expect that a While/EndWhile loop would be restricted to a single context. However, in some cases a call EndWhile can cause the dial plan to jump to another context. We have noticed this with Gosub and Goto.

Here is a simple example:
{code:title=extensions.conf|borderStyle=solid}
[test-while-out]
exten => s,1,Set(i=0)
 same => n,While($[${INC(i)} <= 5])
  same => n,Log(NOTICE,i is ${i})
  same => n,Gosub(test-while-inner,s,1)
 same => n,EndWhile

[test-while-inner]
exten => s,1,Set(j=0)
 same => n,While($[${INC(j)} <= 5])
  same => n,Log(NOTICE,j is ${j})
  same => n,Return
 same => n,EndWhile
 same => n,Return
{code}

And in the Asterisk console execute:
{code:title=Console|borderStyle=solid}
*CLI> originate Local/s at test-while-out application wait 10
    -- Executing [s at test-while-out:1] Set("Local/s at test-while-out-00000008;2", "i=0") in new stack
    -- Executing [s at test-while-out:2] While("Local/s at test-while-out-00000008;2", "1") in new stack
    -- Executing [s at test-while-out:3] Log("Local/s at test-while-out-00000008;2", "NOTICE,i is 1") in new stack
[2015-11-05 16:28:59] NOTICE[27770][C-00000013]: Ext. s:3 @ test-while-out: i is 1
    -- Executing [s at test-while-out:4] Gosub("Local/s at test-while-out-00000008;2", "test-while-inner,s,1") in new stack
    -- Executing [s at test-while-inner:1] Set("Local/s at test-while-out-00000008;2", "j=0") in new stack
    -- Executing [s at test-while-inner:2] While("Local/s at test-while-out-00000008;2", "1") in new stack
    -- Executing [s at test-while-inner:3] Log("Local/s at test-while-out-00000008;2", "NOTICE,j is 1") in new stack
[2015-11-05 16:28:59] NOTICE[27770][C-00000013]: Ext. s:3 @ test-while-inner: j is 1
    -- Executing [s at test-while-inner:4] Return("Local/s at test-while-out-00000008;2", "") in new stack
    -- Executing [s at test-while-out:5] EndWhile("Local/s at test-while-out-00000008;2", "") in new stack
    -- Executing [s at test-while-inner:2] While("Local/s at test-while-out-00000008;2", "1") in new stack
    -- Executing [s at test-while-inner:3] Log("Local/s at test-while-out-00000008;2", "NOTICE,j is 2") in new stack
[2015-11-05 16:28:59] NOTICE[27770][C-00000013]: Ext. s:3 @ test-while-inner: j is 2
    -- Executing [s at test-while-inner:4] Return("Local/s at test-while-out-00000008;2", "") in new stack
[2015-11-05 16:28:59] ERROR[27770][C-00000013]: app_stack.c:378 return_exec: Return without Gosub: stack is empty
  == Spawn extension (test-while-inner, s, 4) exited non-zero on 'Local/s at test-while-out-00000008;2'
{code}

The call starts at test-while-out which contains a While/EndWhile loop. Inside that loop it logs the value of {{i}} and the Gosubs to test-while-inner. The inner context also contains a While/EndWhile loop but we return from inside the loop. In the real world this would be due to some conditional statement. After returning to the outer loop we call EndWhile. I would expect this to bring us back to the beginning of the outer loop. But it actually brings us back to the beginning of the inner loop.


> A call EndWhile can cause the dial plan to jump to another context.
> -------------------------------------------------------------------
>
>                 Key: ASTERISK-25525
>                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-25525
>             Project: Asterisk
>          Issue Type: Bug
>      Security Level: None
>          Components: Applications/app_while, Documentation
>    Affects Versions: 11.6.0
>            Reporter: Steven T. Wheeler
>            Severity: Minor
>
> [Edit by Rusty - Adding a note here at the top for quick reference. The documentation is not sufficient currently. See Richard's comment]
> I would expect that a While/EndWhile loop would be restricted to a single context. However, in some cases a call EndWhile can cause the dial plan to jump to another context. We have noticed this with Gosub and Goto.
> Here is a simple example:
> {code:title=extensions.conf|borderStyle=solid}
> [test-while-out]
> exten => s,1,Set(i=0)
>  same => n,While($[${INC(i)} <= 5])
>   same => n,Log(NOTICE,i is ${i})
>   same => n,Gosub(test-while-inner,s,1)
>  same => n,EndWhile
> [test-while-inner]
> exten => s,1,Set(j=0)
>  same => n,While($[${INC(j)} <= 5])
>   same => n,Log(NOTICE,j is ${j})
>   same => n,Return
>  same => n,EndWhile
>  same => n,Return
> {code}
> And in the Asterisk console execute:
> {code:title=Console|borderStyle=solid}
> *CLI> originate Local/s at test-while-out application wait 10
>     -- Executing [s at test-while-out:1] Set("Local/s at test-while-out-00000008;2", "i=0") in new stack
>     -- Executing [s at test-while-out:2] While("Local/s at test-while-out-00000008;2", "1") in new stack
>     -- Executing [s at test-while-out:3] Log("Local/s at test-while-out-00000008;2", "NOTICE,i is 1") in new stack
> [2015-11-05 16:28:59] NOTICE[27770][C-00000013]: Ext. s:3 @ test-while-out: i is 1
>     -- Executing [s at test-while-out:4] Gosub("Local/s at test-while-out-00000008;2", "test-while-inner,s,1") in new stack
>     -- Executing [s at test-while-inner:1] Set("Local/s at test-while-out-00000008;2", "j=0") in new stack
>     -- Executing [s at test-while-inner:2] While("Local/s at test-while-out-00000008;2", "1") in new stack
>     -- Executing [s at test-while-inner:3] Log("Local/s at test-while-out-00000008;2", "NOTICE,j is 1") in new stack
> [2015-11-05 16:28:59] NOTICE[27770][C-00000013]: Ext. s:3 @ test-while-inner: j is 1
>     -- Executing [s at test-while-inner:4] Return("Local/s at test-while-out-00000008;2", "") in new stack
>     -- Executing [s at test-while-out:5] EndWhile("Local/s at test-while-out-00000008;2", "") in new stack
>     -- Executing [s at test-while-inner:2] While("Local/s at test-while-out-00000008;2", "1") in new stack
>     -- Executing [s at test-while-inner:3] Log("Local/s at test-while-out-00000008;2", "NOTICE,j is 2") in new stack
> [2015-11-05 16:28:59] NOTICE[27770][C-00000013]: Ext. s:3 @ test-while-inner: j is 2
>     -- Executing [s at test-while-inner:4] Return("Local/s at test-while-out-00000008;2", "") in new stack
> [2015-11-05 16:28:59] ERROR[27770][C-00000013]: app_stack.c:378 return_exec: Return without Gosub: stack is empty
>   == Spawn extension (test-while-inner, s, 4) exited non-zero on 'Local/s at test-while-out-00000008;2'
> {code}
> The call starts at test-while-out which contains a While/EndWhile loop. Inside that loop it logs the value of {{i}} and the Gosubs to test-while-inner. The inner context also contains a While/EndWhile loop but we return from inside the loop. In the real world this would be due to some conditional statement. After returning to the outer loop we call EndWhile. I would expect this to bring us back to the beginning of the outer loop. But it actually brings us back to the beginning of the inner loop.



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