Inside a signal handler, you cannot allocate memory because the signal
handler, being implemented with a C
[`signal`](https://en.cppreference.com/w/c/program/signal) call, can be
called _during_ a memory allocation - when that happens, the CTRL-C
handler causes a segfault and/or other inconsistent state.
Similarly, the call can happen from a non-nim thread or inside a C
library function call etc, most of which do not support reentrancy and
therefore cannot be called _from_ a signal handler.
The stack trace facility used in the default handler is unfortunately
beyond fixing without more significant refactoring since it uses
garbage-collected types in its API and implementation.
As an alternative to https://github.com/nim-lang/Nim/pull/25110, this PR
removes the most problematic signal handler, namely the one for SIGINT
(ctrl-c) - SIGINT is special because it's meant to cause a regular
shutdown of the application and crashes during SIGINT handling are both
confusing and, if turned into SIGSEGV, have downstream effects like core
dumps and OS crash reports.
The signal handlers for the various crash scenarios remain as-is - they
may too cause their own crashes but we're already going down in a bad
way, so the harm is more limited - in particular, crashing during a
crash handler corrupts `core`/crash dumps. Users wanting to keep their
core files pristine should continue to use `-d:noSignalHandler` - this
is usually the better option for production applications since they
carry more detail than the Nim stack trace that gets printed.
Finally, the example of a ctrl-c handler performs the same mistake of
calling `echo` which is not well-defined - replace it with an example
that is mostly correct (except maybe for the lack of `volatile` for the
`stop` variable).
(cherry picked from commit 41ce86b577)
* make more standard libraries work with `nimPreviewSlimSystem`
* typo
* part two
* Delete specutils.nim
* fixes more tests
* more fixes
* fixes tests
* fixes three more tests
* add formatfloat import
* fix
* last
* CIs: attempt to use csources_v1
* also updated the BSDs
* also updated azure pipelines
* std modules should not itself use the 'std/' import dir...
* compiler has to be careful with std/ for v1 booting
In case of malformed query string where there is `=` on the value, handle
this character as part of the value instead of throwing an error.
The following query string should no longer crash a program:
key=value&key2=x=1
It will be interpreted as [("key", "value"), ("key2", "x=1")]
This is correct according to latest WhatWG's HTML5 specification
recarding the urlencoded parser:
https://url.spec.whatwg.org/#concept-urlencoded-parser
Older behavior can be restored using the -d:nimLegacyParseQueryStrict
flag.
