AviSynth scripting language bug?

[maxxon]

Has anyone noticed that if you call a function that throws an exception within a try block, all variables are wiped from the stack frame? I mean the entire stack frame is just gone, even in previous function scopes all the way to the top level. But if you throw an exception within the try block without creating another function scope, everything works fine.

Globals don't seem to be affected though.

Here is an example:

global output__junk = BlankClip(height=0, width=0, length=0)
global output__filename = "output.log"
function output(string s)
{
    output__junk.WriteFileStart(output__filename, "s", append=true)
    return 1
}

global g = "GLOBAL"
l = "LOCAL"

function fail
{
    assert(false)
}

try { assert(false) } catch(e) {}
try { output("g="+g) } catch(e) { output("g doesn't exist.  "+e) }
try { output("l="+l) } catch(e) { output("l doesn't exist.  "+e) }

try { fail } catch(e) {}
try { output("g="+g) } catch(e) { output("g doesn't exist.  "+e) }
try { output("l="+l) } catch(e) { output("l doesn't exist.  "+e) }

l = "LOCAL"
try { output("g="+g) } catch(e) { output("g doesn't exist.  "+e) }
try { output("l="+l) } catch(e) { output("l doesn't exist.  "+e) }

output("fn1")
function fn1
{
    l1 = "LOCAL1"

    try { assert(false) } catch(e) {}
    try { output("g="+g) } catch(e) { output("g doesn't exist.  "+e) }
    try { output("l1="+l1) } catch(e) { output("l1 doesn't exist.  "+e) }
}
fn1
try { output("g="+g) } catch(e) { output("g doesn't exist.  "+e) }
try { output("l="+l) } catch(e) { output("l doesn't exist.  "+e) }

output("fn2")
function fn2
{
    l1 = "LOCAL1"

    try { fail } catch(e) {}
    try { output("g="+g) } catch(e) { output("g doesn't exist.  "+e) }
    try { output("l1="+l1) } catch(e) { output("l1 doesn't exist.  "+e) }
}
fn2
try { output("g="+g) } catch(e) { output("g doesn't exist.  "+e) }
try { output("l="+l) } catch(e) { output("l doesn't exist.  "+e) }

The output.log file will contain this:

g=GLOBAL
l=LOCAL
g=GLOBAL
l doesn't exist.  I don't know what "l" means
(test.avs, line 23)
g=GLOBAL
l=LOCAL
fn1
g=GLOBAL
l1=LOCAL1
g=GLOBAL
l=LOCAL
fn2
g=GLOBAL
l1 doesn't exist.  I don't know what "l1" means
(test.avs, line 49)
g=GLOBAL
l doesn't exist.  I don't know what "l" means
(test.avs, line 53)

Has anyone experienced this before? I'm using AviSynth 2.60 May 25 2011.

Strange bug,


Mx