Making the hardcoded string length limit ofThrowable->getTraceAsString() configurable

  110717
June 24, 2020 19:22 tysonandre775@hotmail.com (tyson andre)
Hi internals,

By default, strings in parameter lists are truncated to 15 bytes by default in Throwable->getTraceAsString()
(and Throwable->__toString() as a consequence).
(in Zend/zend_exception.c in `static void _build_trace_args(zval *arg, smart_str *str)`)

This limit is too short to see relevant information such as file paths, full urls, etc, which makes reporting bugs in applications inconvenient.

Would there be any interest in an ini setting such as `exception_string_length_limit` as a non-negative value to raise this (either allowed to be 0 or more or 15 or more, defaulting to 15)

It's possible to manually work around it by calling Throwable->getTrace(), but inconvenient,
and there's always a concern about the user-space trace generation having its own issues
(e.g. https://github.com/phan/phan/blob/3.0.3/src/Phan/Debug/Frame.php#L25-L132)

In applications that don't have a custom exception handler, users could raise this to make creating bug reports easier.

```
php > test('12345678901234567890');
Warning: Uncaught Exception in php shell code:1
Stack trace:
#0 php shell code(1): test('123456789012345...')
#1 {main}
  thrown in php shell code on line 1
```

Thanks,
- Tyson
  110721
June 25, 2020 02:17 ryan.jentzsch@gmail.com (Ryan Jentzsch)
Why is there a 15 byte limit in the first place?

On Wed, Jun 24, 2020, 1:22 PM tyson andre <tysonandre775@hotmail.com> wrote:

> > Hi internals, > > By default, strings in parameter lists are truncated to 15 bytes by > default in Throwable->getTraceAsString() > (and Throwable->__toString() as a consequence). > (in Zend/zend_exception.c in `static void _build_trace_args(zval *arg, > smart_str *str)`) > > This limit is too short to see relevant information such as file paths, > full urls, etc, which makes reporting bugs in applications inconvenient. > > Would there be any interest in an ini setting such as > `exception_string_length_limit` as a non-negative value to raise this > (either allowed to be 0 or more or 15 or more, defaulting to 15) > > It's possible to manually work around it by calling Throwable->getTrace(), > but inconvenient, > and there's always a concern about the user-space trace generation having > its own issues > (e.g. > https://github.com/phan/phan/blob/3.0.3/src/Phan/Debug/Frame.php#L25-L132) > > In applications that don't have a custom exception handler, users could > raise this to make creating bug reports easier. > > ``` > php > test('12345678901234567890'); > Warning: Uncaught Exception in php shell code:1 > Stack trace: > #0 php shell code(1): test('123456789012345...') > #1 {main} > thrown in php shell code on line 1 > ``` > > Thanks, > - Tyson > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: https://www.php.net/unsub.php > >
  110722
June 25, 2020 06:51 alexinbeijing@gmail.com (Alex)
> Why is there a 15 byte limit in the first place?
Presumably it might be so that multi-megabyte strings are not dumped to the console when printing out a stack trace. (Disclaimer: I have not touched the relevant code and am just guessing.)
  110727
June 25, 2020 13:34 tysonandre775@hotmail.com (tyson andre)
> > Why is there a 15 byte limit in the first place? > > Presumably it might be so that multi-megabyte strings are not dumped > to the console when printing out a stack trace. (Disclaimer: I have > not touched the relevant code and am just guessing.)
It apparently dates back to 2003, when exception::getTraceAsString() was first added. https://github.com/php/php-src/commit/c80eb4573f8cbc268463c7ec233b467bd9b36b0f#diff-16cc0fb22dbf90c4c465180255880ea0R167 Arguably, computers have more disk space and better processors. The reasons I can think of to keep a low default limit: - Syslogs might use udp for async logging, which has a limit of 4096 bytes or so, which hasn't changed - Code might truncate before logging an exception, and shorter argument representations would allow logging more frames of the stack trace - Code might log exceptions to disk during abnormal events (e.g. network outages), and too high of a default would fill up disks faster - CLI apps might fill up the entire screen or terminal scrollback buffer with megabyte-long strings (e.g. `string $file_contents`) - Tyson
  110723
June 25, 2020 07:26 thomas.lamy@netwake.de (Thomas Lamy)
Am 24.06.20 um 21:22 schrieb tyson andre:
> Hi internals, > > By default, strings in parameter lists are truncated to 15 bytes by default in Throwable->getTraceAsString() > (and Throwable->__toString() as a consequence). > (in Zend/zend_exception.c in `static void _build_trace_args(zval *arg, smart_str *str)`) > > This limit is too short to see relevant information such as file paths, full urls, etc, which makes reporting bugs in applications inconvenient. > > Would there be any interest in an ini setting such as `exception_string_length_limit` as a non-negative value to raise this (either allowed to be 0 or more or 15 or more, defaulting to 15) > > (....) > > Thanks, > - Tyson
+1, wanted this for years but never got around to tackle it Thomas