Am 2016-05-12 um 23:42 schrieb Vivin Suresh Paliath:
Thanks for the explanation Hannes! The issue with $ makes sense; I ran
into that some time ago - I can't remember the exact situation, but it
was exactly as you described: the $ introduces ambiguity because it is
a valid character and so could be part of the name of the original
function, and not a separator. Would you be able to point me to the
location in the nashorn source where this mapping/translation is done?
It would help me learn more about the internals of nashorn.
The method name is created in Parser#createParserContextFunctionNode:
http://hg.openjdk.java.net/jdk9/dev/nashorn/file/4b118e012ac4/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/parser/Parser.java#l532
The method name for the stack trace is computed in
NashornException#getScriptFrames:
http://hg.openjdk.java.net/jdk9/dev/nashorn/file/4b118e012ac4/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/api/scripting/NashornException.java#l174
I've filed a bug for this: https://bugs.openjdk.java.net/browse/JDK-8156896
Hannes
On Thu, May 12, 2016 at 2:12 PM, Hannes Wallnoefer
<hannes.wallnoe...@oracle.com <mailto:hannes.wallnoe...@oracle.com>>
wrote:
Hi Vivin,
What you see is some fuzziness in the translation from JS
functions to Java methods and from there to the stack traces you see.
When we compile a JS function, we create a Java method with the
name of the function concatenated to the names of its parent
functions, using '$' as separator. For anonymous functions we use
something like L:123 as name where 123 is the line of code where
the function begins.
This method naming scheme helps a lot in making bytecode easier to
debug, and to create unique method names within a compilation
unit. However, it also leads to the stack traces you see, getting
f$foo in the first case and something like L1:foo in the second
case, which is rendered as <anonymous> in the stack trace.
Ideally we should reverse this when printing stack traces,
displaying only the name of the function itself, e.g. "bar" for
"foo$bar" and "<anonymous>" for "foo$L:3". Unfortunately, "$" is a
valid character in a JS identifier, so it's not that easy,
"foo$bar" may also be the name of the original function.
I'm thinking about how to solve this and will probably file an
issue for it.
Hannes
Am 2016-05-12 um 15:59 schrieb Vivin Suresh Paliath:
I tried this out on in chrome and I get the expected stack
trace there. Is
this a bug?
On May 6, 2016 3:39 PM, "Vivin Suresh Paliath"
<vivin.pali...@gmail.com <mailto:vivin.pali...@gmail.com>>
wrote:
I have the following code:
*var f = (function() {*
* return function foo() {*
* try {*
* throw new Error();*
* } catch(e) {*
* print(e.stack);*
* }*
* }*
*})();*
When I call the function, I get the following stacktrace
as expected
(mostly; I was expecting *foo* instead of *f$foo*).
*Error*
* at f$foo (<shell>:1)*
* at <program> (<shell>:1)*
However, if I dynamically construct the function as follows:
*var f = new Function([], "return function foo() { try {
throw new
Error(); } catch(e) { print(e.stack); } }")()*
I get:
*Error*
* at <anonymous> (<function>:2)*
* at <program> (<shell>:1)*
Is there a reason for this discrepancy? Isn't the second
version
effectively the same as the first? Also, why is it *f$foo*
instead of
*foo* in the first case?
I am running jdk8u92.
Thanks!
--
Ruin untold;
And thine own sadness,
Sing in the grass,
When eve has forgot, that no more hear common things that
gleam and pass;
But seek alone to lip, sad Rose of love and ruin untold;
And thine own mother
Can know it as I know
More than another
What makes your own sadness,
Set in her eyes.
map{@n=split//;$j.=$n[0]x$n[1]}split/:/,"01:11:02".
":11:01:11:02:13:01:11:01:11:01:13:02:12:01:13:01".
":11:04:11:06:12:04:11:01:12:01:13:02:12:01:14:01".
":13:01:11:03:12:01:11:04:12:02:11:01:11:01:13:02".
":11:03:11:06:11:01:11:05:12:02:11:01:11:01:13:02".
":11:02:12:01:12:04:11:06:12:01:11:04:12:04:11:01".
":12:03:12:01:12:01:11:01:12:01:12:02:11:01:11:01".
":13:02:11:01:02:11:01:12:02";map{print chr unpack"
i",pack"B32",$_}$j=~m/.{8}/g
--
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linkedin <https://www.linkedin.com/in/vivin>]*
