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.
(cherry picked from commit 26b86c8f4d)
Follow up https://github.com/nim-lang/Nim/pull/19512
ref https://github.com/nim-lang/Nim/issues/24794
Otherwise, `/Users/blue/Desktop/Nim/lib/system/mm/malloc.nim(4, 1)
Error: redefinition of 'allocImpl'; previous declaration here:
/Users/blue/Desktop/Nim/lib/system/memalloc.nim(51, 8)`
In `proc allocImpl*(size: Natural): pointer {.noconv, rtl, tags: [],
benign, raises: [].}`, `rtl` means it is an `importc` function instead
of a proc forward decl.
(cherry picked from commit d15705e05b)
fixes#24664
```nim
proc main() =
for i in 0..1:
var s = "12345"
s.add s
echo s
main()
```
In the given example, `add` contains two steps: `prepareAdd` and
`appendString`. In the first step, a new buffer is created in order to
store the final doubled string. But it doesn't copy the null terminator,
neither zeromem the left unused spaces. It causes a problem because
`appendString` will copy itself which doesn't end with `\0` properly so
contaminated memory is copied instead.
```
var s = 12345\0
prepareAdd:
var s = 12345xxxxx\0
appendString:
var s = 1234512345x
```
(cherry picked from commit 1f07fdd2dc)
ref https://github.com/nim-lang/Nim/pull/24686
With this PR
```nim
import std/streams
proc foo() =
var name = newStringStream("2r2")
raise newException(ValueError, "sh")
try:
foo()
except:
discard
echo 123
```
this example no longer leaks
---------
Co-authored-by: Andreas Rumpf <rumpf_a@web.de>
(cherry picked from commit 510ac84518)
closes https://github.com/nim-lang/RFCs/issues/554
Adds a symmetric difference operation to the language bitset type. This
maps to a simple `xor` operation on the backend and thus is likely
faster than the current alternatives, namely `(a - b) + (b - a)` or `a +
b - a * b`. The compiler VM implementation of bitsets already
implemented this via `symdiffSets` but it was never used.
The standalone binary operation is added to `setutils`, named
`symmetricDifference` in line with [hash
sets](https://nim-lang.org/docs/sets.html#symmetricDifference%2CHashSet%5BA%5D%2CHashSet%5BA%5D).
An operator version `-+-` and an in-place version like `toggle` as
described in the RFC are also added, implemented as trivial sugar.
(cherry picked from commit ae9287c4f3)
updated version of #22193
After #22029 and the followups #23983 and #24005 which fixed issues with
it, `tyFromExpr` no longer match any proc params in generic type bodies
but delay all non-matching calls until the type is instantiated.
Previously the mechanism `fauxMatch` was used to pretend that any
failing match against `tyFromExpr` actually matched, but prevented the
instantiation of the type until later.
Since this mechanism is not needed anymore for `tyFromExpr`, it is now
only used for `tyError` to prevent cascading errors and changed to a
bool field for simplicity. A change in `semtypes` was also needed to
prevent calling `fitNode` on default param values resolving to type
`tyFromExpr` in generic procs for params with non-generic types, as this
would try to coerce the expression into a concrete type when it can't be
instantiated yet.
The aliases `tyProxy` and `tyUnknown` for `tyError` and `tyFromExpr` are
also removed for uniformity.
Lets single threaded applications benefit from tracking foreign cells as
well.
After this, `SmallChunk` technically doesn't need to act as a linked
list anymore I think, gotta investigate that more though.
The likelihood of overflowing `chunk.free` also rises, so to work around
that it might make sense to check `foreignCells` instead of adjusting
free space or replace free with a counter for the local capacity.
For Nim compile I can observe a ~10mb reduction, and smaller ones for
other projects.
Ref: https://github.com/nim-lang/Nim/issues/23788
There was a small leak in the above issue even after fixing the
segfault. The sizes of `free` and `acc` were changed to 32bit because
adding the `foreignCells` field will drastically increase the memory
usage for programs that hold onto memory for a long time if they stay as
64bit.
fixes#23742
Before my PR, `setLen(0)` doesn't free buffer if `s != nil`, but it
allocated unnecessary memory for `strs`. This PR rectifies this
behavior. `setLen(0)` no longer allocates memory for uninitialized
strs/seqs
`reset`, `wasMoved` and `move` doesn't support primitive types, which
generate `null` for these types. It is now produce `x = default(...)` in
the backend. Ideally it should be done by ast2ir in the future
fixes#4695
ref https://github.com/nim-lang/Nim/pull/15818
Since `nkState` is only for the main loop state labels and `nkGotoState`
is used only for dispatching the `:state` (since
https://github.com/nim-lang/Nim/pull/7770), it's feasible to rewrite the
loop body into a single case-based dispatcher, which enables support for
JS, VM backend. `nkState` Node is replaced by a label and Node pair and
`nkGotoState` is only used for intermediary processing. Backends only
need to implement `nkBreakState` and `closureIterSetupExc` to support
closure iterators.
pending https://github.com/nim-lang/Nim/pull/23484
<del> I also observed some performance boost for C backend in the
release mode (not in the danger mode though, I suppose the old
implementation is optimized into computed goto in the danger mode)
</del>
allPathsAsgnResult???
The fix to the atomicArc looks to use `-1` as the check value from the
`SharedPtr` solution. However, it should be `-rcIncrement` since the
refcount is bit shifted in ARC/ORC.
I discovered this playing around doing atomic updates of refcounts in a
user library.
Related to https://github.com/nim-lang/Nim/issues/22711
@ringabout I believe you ported the sharedptr fix?
