feat(streaming)!: remove host_selection/host_shuffle_seed; cycle hosts in declared order

CHANGELOG.md

@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - **`flush_mode` streaming write-flush knob.** The `flush_mode` setting is removed from every binding (Rust `StreamingConfig::flush_mode`, Python `Config.flush_mode`, TypeScript `Config.flushMode` / `setFlushMode`, C++ `set_flush_mode` / `get_flush_mode`, C ABI `thetadatadx_config_set_flush_mode` / `_get_flush_mode`). Outbound streaming writes now always coalesce and flush on the ping heartbeat, so a subscription burst leaves as fewer, larger packets — the terminal's own behavior — with received-data latency unaffected as before. The `"immediate"` per-frame-flush mode existed only to defeat that server-friendly coalescing and is gone. This is a breaking change to the configuration surface.
 
+- **`host_selection` / `host_shuffle_seed` streaming host-ordering knobs.** Removed from every binding (Rust `StreamingConfig::host_selection` / `host_shuffle_seed`, Python `Config.streaming_host_selection` / `streaming_host_shuffle_seed`, TypeScript `Config.streamingHostSelection` / `setStreamingHostSelection` and the shuffle-seed pair, C++ `set_streaming_host_selection` / `get_streaming_host_selection` and the shuffle-seed pair, C ABI `thetadatadx_config_*_streaming_host_selection` / `_host_shuffle_seed`), along with the `HostSelectionPolicy` enum. The client now cycles the declared host list left to right — the terminal's own behavior — and a reconnect tries the last-known-good host first. The per-client fault-domain shuffle and its seed existed only in the SDK, with no terminal counterpart. This is a breaking change to the configuration surface.
+
 ## [0.1.1] - 2026-07-07
 
 ### Added

docs-site/docs/changelog.md

@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - **`flush_mode` streaming write-flush knob.** The `flush_mode` setting is removed from every binding (Rust `StreamingConfig::flush_mode`, Python `Config.flush_mode`, TypeScript `Config.flushMode` / `setFlushMode`, C++ `set_flush_mode` / `get_flush_mode`, C ABI `thetadatadx_config_set_flush_mode` / `_get_flush_mode`). Outbound streaming writes now always coalesce and flush on the ping heartbeat, so a subscription burst leaves as fewer, larger packets — the terminal's own behavior — with received-data latency unaffected as before. The `"immediate"` per-frame-flush mode existed only to defeat that server-friendly coalescing and is gone. This is a breaking change to the configuration surface.
 
+- **`host_selection` / `host_shuffle_seed` streaming host-ordering knobs.** Removed from every binding (Rust `StreamingConfig::host_selection` / `host_shuffle_seed`, Python `Config.streaming_host_selection` / `streaming_host_shuffle_seed`, TypeScript `Config.streamingHostSelection` / `setStreamingHostSelection` and the shuffle-seed pair, C++ `set_streaming_host_selection` / `get_streaming_host_selection` and the shuffle-seed pair, C ABI `thetadatadx_config_*_streaming_host_selection` / `_host_shuffle_seed`), along with the `HostSelectionPolicy` enum. The client now cycles the declared host list left to right — the terminal's own behavior — and a reconnect tries the last-known-good host first. The per-client fault-domain shuffle and its seed existed only in the SDK, with no terminal counterpart. This is a breaking change to the configuration surface.
+
 ## [0.1.1] - 2026-07-07
 
 ### Added

parity.toml

@@ -659,18 +659,6 @@ python = true
 typescript = true
 cpp = true
 
-[[class]]
-name = "StreamingConfig.streaming_host_selection"
-python = true
-typescript = true
-cpp = true
-
-[[class]]
-name = "StreamingConfig.streaming_host_shuffle_seed"
-python = true
-typescript = true
-cpp = true
-
 # `StreamingConfig.consumer_cpu` optional consumer-thread CPU pin,
 # exposed on every binding (Python `Config.consumer_cpu` `Optional[int]`,
 # TypeScript `consumerCpu` / `setConsumerCpu` `number | null`, C++
@@ -1955,15 +1943,14 @@ cpp = true
 returns = "String"
 python_pyi_returns = 'Literal["PROD", "DEV"]'
 
-# The reconnect-jitter and streaming-host-selection readbacks. Both are
-# value-constrained enums exposed as readback getters on every binding: Python
-# (`Config.reconnect_jitter` / `Config.streaming_host_selection` properties),
-# TypeScript (`get reconnectJitter()` / `get streamingHostSelection()`), C++
-# (`Config::get_reconnect_jitter()` / `Config::get_streaming_host_selection()`,
-# each returning the enum's `int` discriminant). The `.pyi` constrains each to
-# its exact value set, pinned via `python_pyi_returns` so a value-set drift
-# fails — without these getter rows the constrained knobs were presence-tracked
-# only (the config-field roster), never type-checked on the stub.
+# The reconnect-jitter readback. A value-constrained enum exposed as a
+# readback getter on every binding: Python (`Config.reconnect_jitter`
+# property), TypeScript (`get reconnectJitter()`), C++
+# (`Config::get_reconnect_jitter()`, returning the enum's `int`
+# discriminant). The `.pyi` constrains it to its exact value set, pinned
+# via `python_pyi_returns` so a value-set drift fails — without this getter
+# row the constrained knob was presence-tracked only (the config-field
+# roster), never type-checked on the stub.
 [[method]]
 class = "Config"
 name = "reconnectJitter"
@@ -1975,17 +1962,6 @@ returns = "String"
 cpp_returns = "i32"
 python_pyi_returns = 'Literal["full", "equal", "decorrelated", "none"]'
 
-[[method]]
-class = "Config"
-name = "streamingHostSelection"
-python = true
-typescript = true
-cpp = true
-[method.signature]
-returns = "String"
-cpp_returns = "i32"
-python_pyi_returns = 'Literal["shuffled", "fixed_order"]'
-
 # Custom reconnect-policy callback registration. A field-shaped getter
 # is meaningless for a callback, so the registration is tracked as a
 # method row (Python `config.reconnect_callback = fn` setter, TS

scripts/ci/check_binding_parity.py

@@ -1861,8 +1861,6 @@ def _collect_rust_pub_fields(config_dir: pathlib.Path) -> dict[str, set[str]]:
     ("StreamingConfig", "keepalive_idle_secs"): "streaming_keepalive_idle_secs",
     ("StreamingConfig", "keepalive_interval_secs"): "streaming_keepalive_interval_secs",
     ("StreamingConfig", "keepalive_retries"): "streaming_keepalive_retries",
-    ("StreamingConfig", "host_selection"): "streaming_host_selection",
-    ("StreamingConfig", "host_shuffle_seed"): "streaming_host_shuffle_seed",
 }
 
 

thetadatadx-cpp/include/thetadatadx.h

@@ -1595,50 +1595,6 @@ void thetadatadx_config_set_streaming_ring_size(ThetaDataDxConfig* config, size_
  */
 int32_t thetadatadx_config_get_streaming_ring_size(const ThetaDataDxConfig* config, size_t* out);
 
-/**
- * Set the streaming host-selection policy.
- *   policy=0: Shuffled (default) -- fault-domain-aware per-client
- *             shuffle; a fleet spreads across hosts and consecutive
- *             failover attempts cross physical machines.
- *   policy=1: FixedOrder -- use the declared host order verbatim.
- * @param config Config handle to mutate.
- * @param policy Host-selection policy selector (0 = Shuffled, 1 = FixedOrder).
- * @return 0 on success, -1 on an invalid policy or null config.
- */
-int32_t thetadatadx_config_set_streaming_host_selection(ThetaDataDxConfig* config, int32_t policy);
-
-/**
- * Read the configured streaming host-selection policy. Same encoding as
- * thetadatadx_config_set_streaming_host_selection.
- * @param config Config handle to read.
- * @param out_policy Receives the host-selection policy on success.
- * @return 0 on success, -1 if either pointer is null.
- */
-int32_t thetadatadx_config_get_streaming_host_selection(const ThetaDataDxConfig* config, int32_t* out_policy);
-
-/**
- * Set the streaming host-shuffle seed using the (has_value, seed) widened
- * shape. Ignored under the FixedOrder policy.
- * @param config Config handle to mutate.
- * @param has_value false (default) derives a fresh per-client seed so a
- *                  fleet shuffles independently; true makes the shuffled
- *                  order deterministic, useful for fleet sharding and tests.
- * @param seed The deterministic seed, honoured only when has_value is true.
- * @return 0 on success, -1 if config is null.
- */
-int32_t thetadatadx_config_set_streaming_host_shuffle_seed(ThetaDataDxConfig* config, bool has_value, uint64_t seed);
-
-/**
- * Read the current streaming host-shuffle seed.
- * @param config Config handle to read.
- * @param out_has_value Receives false for the per-client-entropy sentinel,
- *                      true when an explicit seed is set.
- * @param out_seed Receives the seed when out_has_value is true.
- * @return 0 on success, -1 if any pointer is null.
- */
-int32_t thetadatadx_config_get_streaming_host_shuffle_seed(const ThetaDataDxConfig* config, bool* out_has_value,
-                                              uint64_t* out_seed);
-
 /**
  * Set the wall-clock envelope (seconds) for one market-data-channel
  * retry sequence, measured from the first attempt. 0 disables the

thetadatadx-cpp/tests/error_taxonomy.cpp

@@ -211,8 +211,6 @@ TEST_CASE("config enum setters reject an out-of-domain value with InvalidParamet
     REQUIRE_NOTHROW(cfg.set_reconnect_jitter(2));
     REQUIRE_THROWS_AS(cfg.set_reconnect_jitter(9), thetadatadx::InvalidParameterError);
 
-    REQUIRE_NOTHROW(cfg.set_streaming_host_selection(1));
-    REQUIRE_THROWS_AS(cfg.set_streaming_host_selection(5), thetadatadx::InvalidParameterError);
 }
 
 TEST_CASE("sequence converters reject out-of-wire-range inputs with InvalidParameterError",

thetadatadx-ffi/src/auth.rs

@@ -2216,84 +2216,6 @@ mod resilience_knob_tests {
         }
     }
 
-    #[test]
-    fn fpss_host_selection_and_seed_round_trip() {
-        let cfg = super::thetadatadx_config_production();
-        // SAFETY: handle just returned by thetadatadx_config_production.
-        unsafe {
-            let mut policy: i32 = -1;
-            assert_eq!(
-                super::thetadatadx_config_get_streaming_host_selection(cfg, &mut policy),
-                0
-            );
-            assert_eq!(policy, 0, "default host selection is Shuffled");
-            assert_eq!(
-                super::thetadatadx_config_set_streaming_host_selection(cfg, 1),
-                0
-            );
-            assert_eq!(
-                super::thetadatadx_config_get_streaming_host_selection(cfg, &mut policy),
-                0
-            );
-            assert_eq!(policy, 1);
-            assert_eq!(
-                super::thetadatadx_config_set_streaming_host_selection(cfg, 5),
-                -1,
-                "invalid policy rejected"
-            );
-            assert_eq!(
-                crate::error::thetadatadx_last_error_code(),
-                crate::error::THETADATADX_ERR_INVALID_PARAMETER,
-                "a rejected enum value surfaces the typed invalid-parameter class"
-            );
-
-            let mut has_value = true;
-            let mut seed: u64 = 7;
-            assert_eq!(
-                super::thetadatadx_config_get_streaming_host_shuffle_seed(
-                    cfg,
-                    &mut has_value,
-                    &mut seed
-                ),
-                0
-            );
-            assert!(
-                !has_value,
-                "default seed is the per-client-entropy sentinel"
-            );
-            assert_eq!(seed, 0);
-            assert_eq!(
-                super::thetadatadx_config_set_streaming_host_shuffle_seed(cfg, true, 42),
-                0
-            );
-            assert_eq!(
-                super::thetadatadx_config_get_streaming_host_shuffle_seed(
-                    cfg,
-                    &mut has_value,
-                    &mut seed
-                ),
-                0
-            );
-            assert!(has_value);
-            assert_eq!(seed, 42);
-            assert_eq!(
-                super::thetadatadx_config_set_streaming_host_shuffle_seed(cfg, false, 0),
-                0
-            );
-            assert_eq!(
-                super::thetadatadx_config_get_streaming_host_shuffle_seed(
-                    cfg,
-                    &mut has_value,
-                    &mut seed
-                ),
-                0
-            );
-            assert!(!has_value, "explicit None restores the sentinel");
-
-            super::thetadatadx_config_free(cfg);
-        }
-    }
-
     #[test]
     fn retry_envelope_and_flatfiles_jitter_round_trip() {
         let cfg = super::thetadatadx_config_production();