fixes #22510 (#23100)

(cherry picked from commit 69d0b73d66)

tests/alloc/tmembug.nim

@@ -0,0 +1,54 @@
+discard """
+  joinable: false
+"""
+
+import std / [atomics, strutils, sequtils]
+
+type
+  BackendMessage* = object
+    field*: seq[int]
+
+var
+  chan1: Channel[BackendMessage]
+  chan2: Channel[BackendMessage]
+
+chan1.open()
+chan2.open()
+
+proc routeMessage*(msg: BackendMessage) =
+  discard chan2.trySend(msg)
+
+var
+  recv: Thread[void]
+  stopToken: Atomic[bool]
+
+proc recvMsg() =
+  while not stopToken.load(moRelaxed):
+    let resp = chan1.tryRecv()
+    if resp.dataAvailable:
+      routeMessage(resp.msg)
+      echo "child consumes ", formatSize getOccupiedMem()
+
+createThread[void](recv, recvMsg)
+
+const MESSAGE_COUNT = 100
+
+proc main() =
+  let msg: BackendMessage = BackendMessage(field: (0..500).toSeq())
+  for j in 0..0: #100:
+    echo "New iteration"
+
+    for _ in 1..MESSAGE_COUNT:
+      chan1.send(msg)
+    echo "After sending"
+
+    var counter = 0
+    while counter < MESSAGE_COUNT:
+      let resp = recv(chan2)
+      counter.inc
+    echo "After receiving ", formatSize getOccupiedMem()
+
+  stopToken.store true, moRelaxed
+  joinThreads(recv)
+
+main()

tests/alloc/tmembug2.nim

@@ -0,0 +1,58 @@
+discard """
+  disabled: "true"
+"""
+
+import std / [atomics, strutils, sequtils, isolation]
+
+import threading / channels
+
+type
+  BackendMessage* = object
+    field*: seq[int]
+
+const MESSAGE_COUNT = 100
+
+var
+  chan1 = newChan[BackendMessage](MESSAGE_COUNT*2)
+  chan2 = newChan[BackendMessage](MESSAGE_COUNT*2)
+
+#chan1.open()
+#chan2.open()
+
+proc routeMessage*(msg: BackendMessage) =
+  var m = isolate(msg)
+  discard chan2.trySend(m)
+
+var
+  thr: Thread[void]
+  stopToken: Atomic[bool]
+
+proc recvMsg() =
+  while not stopToken.load(moRelaxed):
+    var resp: BackendMessage
+    if chan1.tryRecv(resp):
+      #if resp.dataAvailable:
+      routeMessage(resp)
+      echo "child consumes ", formatSize getOccupiedMem()
+
+createThread[void](thr, recvMsg)
+
+proc main() =
+  let msg: BackendMessage = BackendMessage(field: (0..5).toSeq())
+  for j in 0..100:
+    echo "New iteration"
+
+    for _ in 1..MESSAGE_COUNT:
+      chan1.send(msg)
+    echo "After sending"
+
+    var counter = 0
+    while counter < MESSAGE_COUNT:
+      let resp = recv(chan2)
+      counter.inc
+    echo "After receiving ", formatSize getOccupiedMem()
+
+  stopToken.store true, moRelaxed
+  joinThreads(thr)
+
+main()