fix(HttpClient): backport retryTransient fixes from v4

Author: codewithkenzo

.changeset/fix-retry-transient-status-codes.md

@@ -0,0 +1,11 @@
+---
+"@effect/platform": patch
+---
+
+Fix `retryTransient` to use correct transient status codes
+
+Changed `isTransientResponse` from `status >= 429` to an explicit allowlist (408, 429, 500, 502, 503, 504). This correctly excludes 501 (Not Implemented) and 505+ permanent errors, while including 408 (Request Timeout) which was previously missed.
+
+Also aligned response retry behavior with v4: the `while` predicate now only applies to error retries, not response retries. Response retries are determined solely by `isTransientResponse`. This matches the semantic intent since `while` is typed for errors, not responses.
+
+Fixes #5995

packages/platform/src/internal/httpClient.ts

@@ -800,9 +800,7 @@ export const retryTransient: {
         mode === "errors-only" ? identity : Effect.repeat({
           schedule: passthroughSchedule,
           times,
-          while: isOnlySchedule || options.while === undefined
-            ? isTransientResponse
-            : Predicate.and(isTransientResponse, options.while)
+          while: isTransientResponse
         }),
         mode === "response-only" ? identity : Effect.retry({
           while: isOnlySchedule || options.while === undefined
@@ -824,7 +822,13 @@ const isTransientHttpError = (error: unknown) =>
   ((error._tag === "RequestError" && error.reason === "Transport") ||
     (error._tag === "ResponseError" && isTransientResponse(error.response)))
 
-const isTransientResponse = (response: ClientResponse.HttpClientResponse) => response.status >= 429
+const isTransientResponse = (response: ClientResponse.HttpClientResponse) =>
+  response.status === 408 ||
+  response.status === 429 ||
+  response.status === 500 ||
+  response.status === 502 ||
+  response.status === 503 ||
+  response.status === 504
 
 /** @internal */
 export const tap = dual<

packages/platform/test/HttpClient.test.ts

@@ -305,4 +305,111 @@ describe("HttpClient", () => {
       Effect.provide(FetchHttpClient.layer),
       Effect.provideService(FetchHttpClient.RequestInit, { redirect: "manual" })
     ), 30000)
+
+  describe("retryTransient", () => {
+    const makeTestClient = (status: number) => {
+      const attemptsRef = Ref.unsafeMake(0)
+      const client = HttpClient.make((request) =>
+        Effect.gen(function*() {
+          yield* Ref.update(attemptsRef, (n) => n + 1)
+          return HttpClientResponse.fromWeb(request, new Response(null, { status }))
+        })
+      )
+      return { client, attemptsRef }
+    }
+
+    it.effect("retries 408 Request Timeout", () =>
+      Effect.gen(function*() {
+        const { client, attemptsRef } = makeTestClient(408)
+        const retryClient = client.pipe(HttpClient.retryTransient({ times: 2 }))
+        yield* retryClient.get("http://test/").pipe(Effect.ignore)
+        const attempts = yield* Ref.get(attemptsRef)
+        strictEqual(attempts, 3)
+      }))
+
+    it.effect("retries 429 Too Many Requests", () =>
+      Effect.gen(function*() {
+        const { client, attemptsRef } = makeTestClient(429)
+        const retryClient = client.pipe(HttpClient.retryTransient({ times: 2 }))
+        yield* retryClient.get("http://test/").pipe(Effect.ignore)
+        const attempts = yield* Ref.get(attemptsRef)
+        strictEqual(attempts, 3)
+      }))
+
+    it.effect("retries 500 Internal Server Error", () =>
+      Effect.gen(function*() {
+        const { client, attemptsRef } = makeTestClient(500)
+        const retryClient = client.pipe(HttpClient.retryTransient({ times: 2 }))
+        yield* retryClient.get("http://test/").pipe(Effect.ignore)
+        const attempts = yield* Ref.get(attemptsRef)
+        strictEqual(attempts, 3)
+      }))
+
+    it.effect("retries 502 Bad Gateway", () =>
+      Effect.gen(function*() {
+        const { client, attemptsRef } = makeTestClient(502)
+        const retryClient = client.pipe(HttpClient.retryTransient({ times: 2 }))
+        yield* retryClient.get("http://test/").pipe(Effect.ignore)
+        const attempts = yield* Ref.get(attemptsRef)
+        strictEqual(attempts, 3)
+      }))
+
+    it.effect("retries 503 Service Unavailable", () =>
+      Effect.gen(function*() {
+        const { client, attemptsRef } = makeTestClient(503)
+        const retryClient = client.pipe(HttpClient.retryTransient({ times: 2 }))
+        yield* retryClient.get("http://test/").pipe(Effect.ignore)
+        const attempts = yield* Ref.get(attemptsRef)
+        strictEqual(attempts, 3)
+      }))
+
+    it.effect("retries 504 Gateway Timeout", () =>
+      Effect.gen(function*() {
+        const { client, attemptsRef } = makeTestClient(504)
+        const retryClient = client.pipe(HttpClient.retryTransient({ times: 2 }))
+        yield* retryClient.get("http://test/").pipe(Effect.ignore)
+        const attempts = yield* Ref.get(attemptsRef)
+        strictEqual(attempts, 3)
+      }))
+
+    it.effect("does NOT retry 200 OK", () =>
+      Effect.gen(function*() {
+        const { client, attemptsRef } = makeTestClient(200)
+        const retryClient = client.pipe(HttpClient.retryTransient({ times: 2 }))
+        yield* retryClient.get("http://test/").pipe(Effect.ignore)
+        const attempts = yield* Ref.get(attemptsRef)
+        strictEqual(attempts, 1)
+      }))
+
+    it.effect("does NOT retry 501 Not Implemented", () =>
+      Effect.gen(function*() {
+        const { client, attemptsRef } = makeTestClient(501)
+        const retryClient = client.pipe(HttpClient.retryTransient({ times: 2 }))
+        yield* retryClient.get("http://test/").pipe(Effect.ignore)
+        const attempts = yield* Ref.get(attemptsRef)
+        strictEqual(attempts, 1)
+      }))
+
+    it.effect("does NOT retry 505 HTTP Version Not Supported", () =>
+      Effect.gen(function*() {
+        const { client, attemptsRef } = makeTestClient(505)
+        const retryClient = client.pipe(HttpClient.retryTransient({ times: 2 }))
+        yield* retryClient.get("http://test/").pipe(Effect.ignore)
+        const attempts = yield* Ref.get(attemptsRef)
+        strictEqual(attempts, 1)
+      }))
+
+    it.effect("while predicate only applies to error retries, not response retries", () =>
+      Effect.gen(function*() {
+        const { client, attemptsRef } = makeTestClient(503)
+        const errorOnlyPredicate = (e: unknown) => e !== null && typeof e === "object" && "_tag" in e
+        const retryClient = client.pipe(HttpClient.retryTransient({
+          times: 2,
+          while: errorOnlyPredicate
+        }))
+        yield* retryClient.get("http://test/").pipe(Effect.ignore)
+        const attempts = yield* Ref.get(attemptsRef)
+        strictEqual(attempts, 3)
+      }))
+  })
 })