Prohibit Flow.take(0)

It can be treated ambiguously (do nothing vs cancel immediately), so we better wait for a user feedback with a use-cases before allowing this

Author: qwwdfsad

kotlinx-coroutines-core/common/src/flow/operators/Limit.kt

@@ -50,8 +50,7 @@ public fun <T> Flow<T>.dropWhile(predicate: suspend (T) -> Boolean): Flow<T> = f
  */
 @FlowPreview
 public fun <T> Flow<T>.take(count: Int): Flow<T> {
-    require(count >= 0) { "Requested element count $count is less than zero." }
-    if (count == 0) return emptyFlow()
+    require(count > 0) { "Requested element count $count should be positive" }
     return flow {
         var consumed = 0
         try {

kotlinx-coroutines-core/common/test/flow/operators/TakeTest.kt

@@ -28,13 +28,15 @@ class TakeTest : TestBase() {
     }
 
     @Test
-    fun testNonPositiveValues() = runTest {
+    fun testNonPositiveValues() {
         val flow = flowOf(1)
         assertFailsWith<IllegalArgumentException> {
             flow.take(-1)
         }
 
-        assertNull(flow.take(0).singleOrNull())
+        assertFailsWith<IllegalArgumentException> {
+            flow.take(0)
+        }
     }
 
     @Test