Copying StackTraceEntry instances when nimStackTraceOverride is defined
breaks the link between a cstring field that's supposed to point at
another string field in the same object.
Sometimes, the original object is garbage collected, that memory region
reused for storing other strings, so when the StackTraceEntry copy tries
to use its cstring pointer to construct a traceback message, it accesses
unrelated strings.
This only happens for async tracebacks and this patch prevents that by
making sure we only use the string fields when nimStackTraceOverride is
defined.
Async tracebacks also beautified slightly by getting rid of an extra line
that was supposed to be commented out, along with the corresponding debugging output.
There's also a micro-optimisation to avoid concatenating two strings just
to get their combined length.
(cherry picked from commit a1c82c39af)
* nimStackTraceOverride: enable stack traces in exceptions
This is a two-step stack trace collection scheme, because re-raised
exceptions will collect multiple stack traces but use them rarely, when
printing info about an uncaught exception, so it makes sense to only do
the cheap stack unwinding all the time and the relatively expensive
debugging information collection on-demand.
`asyncfutures` implements its own `$` proc for printing
`seq[StackTraceEntry]`, so we have to add the debugging info there, just
like we do for the private `$` proc in `system/excpt`.
* cleaned up PR #15284
Co-authored-by: Ștefan Talpalaru <stefantalpalaru@yahoo.com>
(cherry picked from commit 1fae66e4df)
* stacktraces can now show custom runtime msgs
* improve tests/stdlib/tstackframes.nim
* fix test for --gc:arc
* test --stacktraceMsgs:on and --stacktraceMsgs:off
* --stacktracemsgs:off by default
* config update
* disable a questionable test
* remove c++ exception handling IDs, new impl doesn't require it anymore
* C++ based exceptions finally work
* fixes bootstrapping problem in C++ mode
* teach GCC it's 2020 now
* more bugfixes for C++ based exception handling
* apply cooldome's patch
* another attempt to enable C++11
* bug fix
Co-authored-by: Araq <rumpf_a@web.de>
Co-authored-by: cooldome <ariabushenko@bk.ru>
