feat(streaming)!: trim reconnect_jitter to full/none; drop equal + decorrelated (#1197)

* feat(streaming)!: trim reconnect_jitter to full/none; drop equal + decorrelated

The reconnect backoff exposed four AWS jitter modes — Full, Equal, Decorrelated, None. Full jitter (sample uniformly from [0, delay]) is the right default for a recovering fleet and stays; None (deterministic) is kept for tests. Equal and Decorrelated were unused academic variants with no operational benefit over full jitter — flexibility nobody sets — so they are removed.

The JitterMode enum drops both variants (its sampler no longer needs the per-burst BackoffSchedule, so the now-dead decorrelated walk state — the schedule's `prev` field and `reset()` — is removed too), and the C-ABI integer encoding collapses to 0 = Full, 1 = None. Removed across every binding, the config surface, the cross-binding parity rows, and the docs; setting the removed modes (or the old C-ABI codes 1 = Equal / 2 = Decorrelated) is now rejected with the typed invalid-parameter error.

Breaking change to the configuration surface.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* test(cpp): update reconnect_jitter round-trip to the 2-mode encoding

The C++ error-taxonomy test set reconnect_jitter(2) (the removed Decorrelated code) as its valid non-default value; use 1 (None) now that the encoding is 0=Full, 1=None.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: preview <noreply@anthropic.com>

Author: userFRM

CHANGELOG.md

@@ -13,6 +13,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - **`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.
 
+- **`reconnect_jitter` trimmed to `"full"` / `"none"`.** The `"equal"` and `"decorrelated"` jitter variants are removed from every binding (the `JitterMode` enum drops them, and the C-ABI integer encoding is now `0 = Full`, `1 = None`). Full jitter — sampling uniformly from `[0, delay]` — stays the default and is the right choice for a recovering fleet; `"none"` (deterministic delays) remains for tests. The two removed variants were unused academic backoff modes with no operational benefit over full jitter. Setting `reconnect_jitter` to `"equal"` or `"decorrelated"` (or the C-ABI codes `1` / `2`) is now rejected. This is a breaking change to the configuration surface.
+
 ## [0.1.1] - 2026-07-07
 
 ### Added

docs-site/docs/changelog.md

@@ -13,6 +13,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - **`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.
 
+- **`reconnect_jitter` trimmed to `"full"` / `"none"`.** The `"equal"` and `"decorrelated"` jitter variants are removed from every binding (the `JitterMode` enum drops them, and the C-ABI integer encoding is now `0 = Full`, `1 = None`). Full jitter — sampling uniformly from `[0, delay]` — stays the default and is the right choice for a recovering fleet; `"none"` (deterministic delays) remains for tests. The two removed variants were unused academic backoff modes with no operational benefit over full jitter. Setting `reconnect_jitter` to `"equal"` or `"decorrelated"` (or the C-ABI codes `1` / `2`) is now rejected. This is a breaking change to the configuration surface.
+
 ## [0.1.1] - 2026-07-07
 
 ### Added

docs-site/docs/streaming/reliability.md

@@ -27,7 +27,7 @@ All on the [configuration object](/articles/configuration), prefixed `reconnect_
 |---|---|---|
 | `reconnect_policy` | `"auto"` | `"auto"` recovers automatically; `"manual"` never reconnects (you call `reconnect()`); `"custom"` uses your callback. |
 | `reconnect_wait_ms` / `reconnect_wait_max_ms` | 250 / 30000 | Exponential backoff ladder: initial delay and cap. |
-| `reconnect_jitter` | `"full"` | Jitter mode: `"full"`, `"equal"`, `"decorrelated"`, `"none"`. |
+| `reconnect_jitter` | `"full"` | Jitter mode: `"full"`, `"none"`. |
 | `reconnect_max_attempts` | 30 | Attempt budget for transient drops. |
 | `reconnect_max_elapsed_secs` | 300 | Wall-clock cap on one recovery sequence; `0` disables. |
 | `reconnect_wait_rate_limited_ms` / `reconnect_max_rate_limited_attempts` | 130000 / 100 | Floor and budget for rate-limited drops. |

parity.toml

@@ -1960,7 +1960,7 @@ cpp = true
 [method.signature]
 returns = "String"
 cpp_returns = "i32"
-python_pyi_returns = 'Literal["full", "equal", "decorrelated", "none"]'
+python_pyi_returns = 'Literal["full", "none"]'
 
 # Custom reconnect-policy callback registration. A field-shaped getter
 # is meaningless for a callback, so the registration is tracked as a

thetadatadx-cpp/include/config_accessors.hpp.inc

@@ -1378,11 +1378,9 @@ int32_t thetadatadx_config_get_reconnect_wait_server_restart_ms(const ThetaDataD
 /**
  * Set the jitter strategy applied to every reconnect delay.
  *   mode=0: Full (default) -- sample uniformly from [0, delay].
- *   mode=1: Equal -- delay/2 + uniform(0, delay/2).
- *   mode=2: Decorrelated -- walk relative to the previous delay.
- *   mode=3: None -- deterministic delays (tests only).
+ *   mode=1: None -- deterministic delays (tests only).
  * @param config Config handle to mutate.
- * @param mode Jitter strategy selector (0-3 per the list above).
+ * @param mode Jitter strategy selector (0 = Full, 1 = None).
  * @return 0 on success, -1 on an invalid mode or null config.
  */
 int32_t thetadatadx_config_set_reconnect_jitter(ThetaDataDxConfig* config, int32_t mode);

thetadatadx-cpp/include/thetadatadx.h

@@ -208,7 +208,7 @@ TEST_CASE("config enum setters reject an out-of-domain value with InvalidParamet
     // throw.
     auto cfg = thetadatadx::Config::production();
 
-    REQUIRE_NOTHROW(cfg.set_reconnect_jitter(2));
+    REQUIRE_NOTHROW(cfg.set_reconnect_jitter(1));
     REQUIRE_THROWS_AS(cfg.set_reconnect_jitter(9), thetadatadx::InvalidParameterError);
 
 }

thetadatadx-cpp/tests/error_taxonomy.cpp

@@ -2115,7 +2115,7 @@ mod resilience_knob_tests {
                 0
             );
             assert_eq!(mode, 0, "default jitter mode is Full");
-            for m in [1, 2, 3, 0] {
+            for m in [1, 0] {
                 assert_eq!(super::thetadatadx_config_set_reconnect_jitter(cfg, m), 0);
                 assert_eq!(
                     super::thetadatadx_config_get_reconnect_jitter(cfg, &mut mode),

thetadatadx-ffi/src/auth.rs

@@ -225,8 +225,8 @@ class Config:
     """Back-off floor, in milliseconds, applied to the rate-limited (TooManyRequests) failure class (default 130_000)."""
     reconnect_wait_server_restart_ms: int
     """Flat reconnect cadence, in milliseconds, applied to the ServerRestarting failure class (default 5_000)."""
-    reconnect_jitter: Literal["full", "equal", "decorrelated", "none"]
-    """Jitter strategy applied to every reconnect delay: ``"full"`` (default), ``"equal"``, ``"decorrelated"``, or ``"none"``."""
+    reconnect_jitter: Literal["full", "none"]
+    """Jitter strategy applied to every reconnect delay: ``"full"`` (default) or ``"none"``."""
     reconnect_replay_burst_size: int
     """Number of subscription-replay frames sent per burst after an auto-reconnect (default 50, minimum 1)."""
     reconnect_replay_pace_ms: int