Keep Stream.range advancing with a zero-sized chunk

.changeset/fix-stream-range-zero-chunk.md

@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+Ensure `Stream.range` emits the full range when the chunk size is zero.

packages/effect/src/Stream.ts

@@ -1570,14 +1570,15 @@ export const range = (
   chunkSize = Channel.DefaultChunkSize
 ): Stream<number> =>
   min > max ? empty : fromPull(Effect.sync(() => {
+    const size = Math.max(1, chunkSize)
     let start = min
     let done = false
     return Effect.suspend(() => {
       if (done) return Cause.done()
       const remaining = max - start + 1
-      if (remaining > chunkSize) {
-        const chunk = Arr.range(start, start + chunkSize - 1)
-        start += chunkSize
+      if (remaining > size) {
+        const chunk = Arr.range(start, start + size - 1)
+        start += size
         return Effect.succeed(chunk)
       }
       const chunk = Arr.range(start, start + remaining - 1)

packages/effect/test/Stream.test.ts

@@ -404,6 +404,16 @@ describe("Stream", () => {
         assert.deepStrictEqual(result, [1, 2, 3])
       }))
 
+    it.effect("range - zero chunk size does not change the emitted range", () =>
+      Effect.gen(function*() {
+        const result = yield* Stream.range(1, 3, 0).pipe(
+          Stream.take(4),
+          Stream.runCollect
+        )
+
+        assert.deepStrictEqual(result, [1, 2, 3])
+      }))
+
     it.effect("service", () =>
       Effect.gen(function*() {
         const result = yield* Stream.service(Greeter).pipe(