From 05c8e1d85da4aec8042c8d613e2744feeda2ae5b Mon Sep 17 00:00:00 2001
From: ringabout <43030857+ringabout@users.noreply.github.com>
Date: Fri, 5 Dec 2025 07:46:47 +0800
Subject: [PATCH] fixes #25324; Channel incorrectly takes a sink argument in
 refc (#25328)
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… it performs a deep copy internally

fixes #25324

notes that
> Enabling `-d:nimPreviewSlimSystem` removes the import of
`channels_builtin` in
in the `system` module, which is replaced by
[threading/channels](https://github.com/nim-lang/threading/blob/master/threading/channels.nim).

(cherry picked from commit 5d4829415a575b02cd2c56fee841ec111496cb50)
---
 lib/system/channels_builtin.nim | 38 ++++++++++++++++++++++-----------
 1 file changed, 25 insertions(+), 13 deletions(-)

diff --git a/lib/system/channels_builtin.nim b/lib/system/channels_builtin.nim
index 799546a16d..1cc9443778 100644
--- a/lib/system/channels_builtin.nim
+++ b/lib/system/channels_builtin.nim
@@ -367,23 +367,35 @@ proc sendImpl(q: PRawChannel, typ: PNimType, msg: pointer, noBlock: bool): bool
   releaseSys(q.lock)
   result = true
 
-proc send*[TMsg](c: var Channel[TMsg], msg: sink TMsg) {.inline.} =
-  ## Sends a message to a thread. `msg` is deeply copied.
-  discard sendImpl(cast[PRawChannel](addr c), cast[PNimType](getTypeInfo(msg)), unsafeAddr(msg), false)
-  when defined(gcDestructors):
+when defined(gcDestructors):
+  proc send*[TMsg](c: var Channel[TMsg], msg: sink TMsg) {.inline.} =
+    ## Sends a message to a thread.
+    discard sendImpl(cast[PRawChannel](addr c), cast[PNimType](getTypeInfo(msg)), unsafeAddr(msg), false)
     wasMoved(msg)
 
-proc trySend*[TMsg](c: var Channel[TMsg], msg: sink TMsg): bool {.inline.} =
-  ## Tries to send a message to a thread.
-  ##
-  ## `msg` is deeply copied. Doesn't block.
-  ##
-  ## Returns `false` if the message was not sent because number of pending items
-  ## in the channel exceeded `maxItems`.
-  result = sendImpl(cast[PRawChannel](addr c), cast[PNimType](getTypeInfo(msg)), unsafeAddr(msg), true)
-  when defined(gcDestructors):
+  proc trySend*[TMsg](c: var Channel[TMsg], msg: sink TMsg): bool {.inline.} =
+    ## Tries to send a message to a thread.
+    ##
+    ## Doesn't block.
+    ##
+    ## Returns `false` if the message was not sent because number of pending items
+    ## in the channel exceeded `maxItems`.
+    result = sendImpl(cast[PRawChannel](addr c), cast[PNimType](getTypeInfo(msg)), unsafeAddr(msg), true)
     if result:
       wasMoved(msg)
+else:
+  proc send*[TMsg](c: var Channel[TMsg], msg: TMsg) {.inline.} =
+    ## Sends a message to a thread. `msg` is deeply copied.
+    discard sendImpl(cast[PRawChannel](addr c), cast[PNimType](getTypeInfo(msg)), unsafeAddr(msg), false)
+
+  proc trySend*[TMsg](c: var Channel[TMsg], msg: TMsg): bool {.inline.} =
+    ## Tries to send a message to a thread.
+    ##
+    ## `msg` is deeply copied. Doesn't block.
+    ##
+    ## Returns `false` if the message was not sent because number of pending items
+    ## in the channel exceeded `maxItems`.
+    result = sendImpl(cast[PRawChannel](addr c), cast[PNimType](getTypeInfo(msg)), unsafeAddr(msg), true)
 
 proc llRecv(q: PRawChannel, res: pointer, typ: PNimType) =
   q.ready = true