From 413395866f1caa5046164b4e43ceed64ca60103a Mon Sep 17 00:00:00 2001
From: ringabout <43030857+ringabout@users.noreply.github.com>
Date: Wed, 2 Aug 2023 16:58:29 +0800
Subject: [PATCH] fixes #22360; compare with the half of randMax (#22361)

* fixes #22360; compare with the half of randMax

* add a test

(cherry picked from commit f3a7622514f24740c6b33f0c37ebe6339ad5b70d)
---
 lib/pure/random.nim      |  5 +----
 tests/stdlib/trandom.nim | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/lib/pure/random.nim b/lib/pure/random.nim
index 422f42a8b8..88616594b1 100644
--- a/lib/pure/random.nim
+++ b/lib/pure/random.nim
@@ -381,10 +381,7 @@ proc rand*[T: Ordinal](r: var Rand; t: typedesc[T]): T {.since: (1, 7, 1).} =
   when T is range or T is enum:
     result = rand(r, low(T)..high(T))
   elif T is bool:
-    whenJsNoBigInt64:
-      result = (r.next or 0) < 0
-    do:
-      result = cast[int64](r.next) < 0
+    result = r.next < randMax div 2
   else:
     whenJsNoBigInt64:
       result = cast[T](r.next shr (sizeof(uint)*8 - sizeof(T)*8))
diff --git a/tests/stdlib/trandom.nim b/tests/stdlib/trandom.nim
index 8784b33ee4..920d429d4f 100644
--- a/tests/stdlib/trandom.nim
+++ b/tests/stdlib/trandom.nim
@@ -282,3 +282,21 @@ block: # bug #17898
       for j in 0..<numRepeat:
         discard rands[i].next
         doAssert rands[i] notin randSet
+
+block: # bug #22360
+  const size = 1000
+  var fc = 0
+  var tc = 0
+
+  for _ in 1..size:
+    let s = rand(bool)
+
+    if s:
+      inc tc
+    else:
+      inc fc
+
+  when defined(js):
+    doAssert (tc, fc) == (483, 517), $(tc, fc)
+  else:
+    doAssert (tc, fc) == (510, 490), $(tc, fc)