...introduced by me in #24792. Sorry.
This fix doesn't avoid copying the `restrictedBody` twice in the
generated code but has the benefit of working.
Proper fix needs a detection that can set a const bool for a module
once. `when nimvm` is restricted in use and is difficult to dance
around. Some details in: #12517, #12518, #13038
I might have copied the buggy solution from some discussion and it might
have worked at some point, but it's small excuse.
fixes#24998
Basically it retraces back to the situation before
https://github.com/nim-lang/Nim/pull/18366 and
https://github.com/nim-lang/Nim/pull/18362, i.e.
```nim
import fuzz/a
import fuzz/a
```
```nim
import fuzz/a
from buzz/a
```
```nim
import fuzz/a except nil
from fuzz/a import addInt
```
All of these cases are now flagged as invalid and triggers a
redefinition error, i.e., each module name importing is treated as
consistent as the symbol definition
kinda annoying for importing/exporting with `when conditions` though
ref https://github.com/nim-lang/Nim/issues/18762https://github.com/nim-lang/Nim/issues/20907
```nim
from std/strutils import toLower
when not defined(js):
from std/strutils import toUpper
```
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).
Raising exceptions halfway through a memory allocation is undefined
behavior since exceptions themselves require multiple allocations and
the allocator functions are not reentrant.
It is of course also expensive performance-wise to introduce lots of
exception-raising code everywhere since it breaks many optimisations and
bloats the code.
Finally, performing pointer arithmetic with signed integers is incorrect
for example on on a 32-bit systems that allows up to 3gb of address
space for applications (large address extensions) and unnecessary
elsewhere - broadly, stuff inside the memory allocator is generated by
the compiler or controlled by the standard library meaning that
applications should not be forced to pay this price.
If we wanted to check for overflow, the right way would be in the
initial allocation location where both the size and count of objects is
known.
The code is updated to use the same arithmetic operator style as for
refc with unchecked operations rather than disabling overflow checking
wholesale in the allocator module - there are reasons for both, but
going with the existing flow seems like an easier place to start.
Also added some documentation to the header.
See: https://forum.nim-lang.org/t/13311
> I did try using the flag, but couldn't get it to work. If I do
-d:nimIoSelector, the defined check passes, but the other code fails to
compile because there is no const named nimIoSelector. It seemed like a
bug to me, do you have a working number compiler invocation?
Co-authored-by: ringabout <43030857+ringabout@users.noreply.github.com>
`DWORD` is defined as `int32`, so `DWORD(...)` would not work as
expected. When writing to files larger than 2GB, exception occurs:
```
unhandled exception: value out of range: 4294967295 notin -2147483648 .. 2147483647 [RangeDefect]
```
This PR is a quick fix for this.
P.S. Why `DWORD` is defined as `int32`?
Reverts nim-lang/Nim#25090
It seems to cause problems for C++ and i686
```
2025-08-08T02:37:55.5976232Z c:/a/nightlies/nightlies/external/mingw32/bin/../lib/gcc/i686-w64-mingw32/11.1.0/../../../../i686-w64-mingw32/bin/ld.exe: C:\Users\runneradmin\nimcache\manual_experimental_snippet_106_d\@pstd@sprivate@ssyslocks.nim.c.o:@pstd@sprivate@ssyslocks.nim.c:(.text+0x29): undefined reference to `SleepConditionVariableCS'
2025-08-08T02:37:55.5978066Z c:/a/nightlies/nightlies/external/mingw32/bin/../lib/gcc/i686-w64-mingw32/11.1.0/../../../../i686-w64-mingw32/bin/ld.exe: C:\Users\runneradmin\nimcache\manual_experimental_snippet_106_d\@pthreadpool.nim.c.o:@pthreadpool.nim.c:(.text+0x26): undefined reference to `InitializeConditionVariable'
2025-08-08T02:37:55.5980101Z c:/a/nightlies/nightlies/external/mingw32/bin/../lib/gcc/i686-w64-mingw32/11.1.0/../../../../i686-w64-mingw32/bin/ld.exe: C:\Users\runneradmin\nimcache\manual_experimental_snippet_106_d\@pthreadpool.nim.c.o:@pthreadpool.nim.c:(.text+0x116): undefined reference to `WakeConditionVariable'
2025-08-08T02:37:55.5981093Z collect2.exe: error: ld returned 1 exit status
2025-08-08T02:37:55.5988564Z Error: execution of an external program failed: 'gcc.exe -o
```
- Added support for SOCKS5h (h for proxy-side DNS resolving) to
httpclient
- Deprecated `auth` arguments for `newProxy` constructors, for auth to
be embedded in the url.
Unfortunately `http://example.com` is not currently reachable from
github CI, so the tests fail there for a few days already, I'm not sure
what can be done here.
fixes#25007
```nim
proc setLengthSeqUninit(s: PGenericSeq, typ: PNimType, newLen: int, isTrivial: bool): PGenericSeq {.
compilerRtl.} =
```
In this added function, only the line `zeroMem(dataPointer(result,
elemAlign, elemSize, newLen), (result.len-%newLen) *% elemSize)` is
removed from `proc setLengthSeqV2` when enlarging a sequence.
JS and VM versions simply use `setLen`.
Reworked closureiter transformation.
- Convolutedly nested finallies should cause no problems now.
- CurrentException state now follows nim runtime rules (pushes and pops
appropriately), and mimics normal code, which is somewhat buggy, see
#25031
- Previously state optimization (removing empty states or extra jumps)
missed some opportunities, I've reimplemented it to do everything
possible to optimize the states. At this point any extra states or jumps
should be considered a bug.
The resulting codegen (compiled binaries) is also slightly smaller.
**BUT:**
- I had to change C++ reraising logic, see expt.nim. Because with
closure iters `currentException` is not always in sync with C++'s notion
of current exception. From my tests and understanding of C++ runtime
there should not be any problems, but I'm only 99% sure :)
- I've reused `nfNoRewrite` flag in one specific case during the
transformation. This flag is also used in term-rewriting logic. Again,
99% sure, these 2 scenarios will never intersect.
Docs are routinely compiled on a different OS so often don't reflect
reality of CT-conditionals.
I bet there's a few of other places like this in the stdlib.
todo: We can also give a deprecation message for `ltPtr`/`lePtr`
matching for cstring in `magicsAfterOverloadResolution`
follow up https://github.com/nim-lang/Nim/pull/24942
explaining why the result may not be so surprising. Clean-up of stray
whitespace and insert of missing "in" along for the ride.
It's just not always faster or slower than `Table`. The difference
depends upon many factors such as (at least!): A) how much (if anything
- for `int` keys it is nothing) hash-comparison before `==` comparison
saves B) how much resizing happens (which may even vary from run to run
if end users are allowed to provide scale guess input), C) how much
comparison happens at all (i.e., table density), D) how much space/size
matters - like how close to a specific deployment "available" cache size
the table is.
If we want, we could add a sentence suggesting performance fans also try
`Table`, but the kind of low-level nature of the explanation strikes me
as already along those lines.
Fixes#24895
- Remove all bio handling
- Remove all `sendPendingSslData` which only seems to make things work
by chance
- Wrap the client socket on `acceptAddr` (std/net does this)
- Do the SSL handshake on accept (std/net does this)
The only concern is if addWrite/addRead works well on Windows.
On windows, `HANDLE` type values are converted to `syncio.FileHandle` in
`lib/std/syncio.nim`, `lib/pure/memfiles.nim` and `lib/pure/osproc.nim`.
`HANDLE` type is `void *` on Windows and its size is larger then `cint`.
https://learn.microsoft.com/en-us/windows/win32/winprog/windows-data-types
This PR change `syncio.FileHandle` type so that converting `HANDLE` type
to `syncio.FileHandle` doesn't lose bits.
We can keep `FileHandle` unchanged and change some of parameter/return
type from `FileHandle` to an type same size to `HANDLE`, but it is
breaking change.
ref https://github.com/nim-lang/Nim/issues/24764
To keep destructors injected consistently, we need to transform `mAsgn`
properly into `nkSinkAsgn` and `nkAsgn`. This PR is the first step
towards overhauling hook injections.
In this PR, hooks (except mAsgn) are treated consistently whether it is
resolved in matching or instantiated by sempass2. It also fixes a
spelling `=wasMoved` to its normalized version, which caused no
replacing generic hook calls with lifted hook calls.
implements https://github.com/nim-lang/RFCs/issues/557
It inserts defect handing into a bare except branch
```nim
try:
raiseAssert "test"
except:
echo "nope"
```
=>
```nim
try:
raiseAssert "test"
except:
# New behaviov, now well-defined: **never** catches the assert, regardless of panic mode
raiseDefect()
echo "nope"
```
In this way, `except` still catches foreign exceptions, but panics on
`Defect`. Probably when Nim has `except {.foreign.}`, we can extend
`raiseDefect` to foreign exceptions as well. That's supposed to be a
small use case anyway.
`--legacy:noPanicOnExcept` is provided for a transition period.
fixes#24837
I really wanted to name the variable just `stream` and leave `defer:
...` and `result =...` out, but the compiler says the variable is
redefined, so this is the form.
This change adds `withValue` templates for the `Table` type that are
able to operate on immutable table values -- the existing implementation
requires a `var`.
This is needed for situations where performance is sensitive. There are
two goals with my implementation:
1. Don't create a copy of the value in the table. That's why I need the
`cursor` pragma. Otherwise, it would copy the value
2. Don't double calculate the hash. That's kind of intrinsic with this
implementation. But the only way to achieve this without this PR is to
first check `if key in table` then to read `table[key]`
I brought this up in the discord and a few folks tried to come up with
options that were as fast as this, but nothing quite matched the
performance here. Thread starts here:
https://discord.com/channels/371759389889003530/371759389889003532/1355206546966974584
- Allows using with `--experimental:strictFuncs`
- `{.cast(noSideEffect).}:` inside the proc was required to mutate
`s.len`, same as used in `newSeqImpl`.
- Removed now unnecessary `noSideEffect` casts in `system.nim`
-
Closes#24811
Co-authored-by: ringabout <43030857+ringabout@users.noreply.github.com>
- `system.substr` now uses `copymem` when available, introducing a small
template for nimvm detection (#12517#12518)
- Docs are updated to clarify behaviour on out-of-bounds input
- Runnable examples cover more edge cases and do not repeat between
overloads
- Docs now explain the difference between overloads
What bothers me is that the `substr*(a: openArray[char]): string =`
which was added by @beef331 is practically an implementation of #14810,
which is just a conversion from `openArray` to `string` but somehow it
ended up being a `substr` overload, even though its behaviour is totally
different, _the "substringing" is performed by a previous step_
(conversion to openArray) and the bounds are not checked. I'm not sure
it's that great for overloads to differ in subtle ways so much.
What are the cases that `substr` covers now, that prohibit renaming it
to `toString` (or something like that)?
Multiple replacements based on character sets in a single pass. Useful
for string sanitation. Follows existing `multiReplace` semantics.
Note: initially copied the substring version logic with a `while` and a
named block break, but Godbolt showed it had produced slightly larger
assembly using higher registers than the final version.
- [x] Tests
- [x] changelog.md
