✨ Add file policy drift checks

bitlogger/BitLogger_test.mbt

@@ -337,6 +337,7 @@ test "configured logger file setters update file sink policy state" {
   inspect(default_policy.append, content="true")
   inspect(default_policy.auto_flush, content="true")
   inspect(default_policy.rotation is None, content="true")
+  inspect(logger.file_policy_matches_default(), content="true")
   inspect(logger.file_set_append_mode(false), content="true")
   inspect(logger.file_append_mode(), content="false")
   inspect(logger.file_set_auto_flush(false), content="true")
@@ -363,10 +364,12 @@ test "configured logger file setters update file sink policy state" {
   inspect(policy.append, content="false")
   inspect(policy.auto_flush, content="false")
   inspect(policy.rotation is None, content="true")
+  inspect(logger.file_policy_matches_default(), content="false")
   inspect(logger.file_reset_policy(), content="true")
   inspect(logger.file_append_mode(), content="true")
   inspect(logger.file_auto_flush(), content="true")
   inspect(logger.file_rotation_config() is None, content="true")
+  inspect(logger.file_policy_matches_default(), content="true")
   ignore(logger.close())
 }
 
@@ -385,12 +388,14 @@ test "configured logger reset policy restores configured file defaults" {
   let default_policy = logger.file_default_policy()
   inspect(default_policy.append, content="false")
   inspect(default_policy.auto_flush, content="false")
+  inspect(logger.file_policy_matches_default(), content="true")
   inspect(logger.file_set_append_mode(true), content="true")
   inspect(logger.file_set_auto_flush(true), content="true")
   inspect(logger.file_clear_rotation(), content="true")
   inspect(logger.file_reset_policy(), content="true")
   inspect(logger.file_append_mode(), content="false")
   inspect(logger.file_auto_flush(), content="false")
+  inspect(logger.file_policy_matches_default(), content="true")
   match logger.file_rotation_config() {
     Some(rotation) => {
       inspect(rotation.max_bytes, content="36")
@@ -431,6 +436,7 @@ test "configured logger set policy applies bundled runtime file policy" {
   inspect(default_policy.append, content="true")
   inspect(default_policy.auto_flush, content="true")
   inspect(default_policy.rotation is None, content="true")
+  inspect(logger.file_policy_matches_default(), content="false")
   ignore(logger.close())
 }
 
@@ -440,6 +446,7 @@ test "configured non-file logger cannot reset file policy" {
   inspect(logger.file_policy().append, content="false")
   inspect(logger.file_default_policy().append, content="false")
   inspect(logger.file_set_policy(FileSinkPolicy::new()), content="false")
+  inspect(logger.file_policy_matches_default(), content="false")
 }
 
 test "configured logger can reopen built file sink" {

bitlogger/BitLogger_wbtest.mbt

@@ -137,6 +137,7 @@ test "file sink setters update auto flush and rotation state" {
   inspect(default_policy.append, content="true")
   inspect(default_policy.auto_flush, content="true")
   inspect(default_policy.rotation is None, content="true")
+  inspect(sink.policy_matches_default(), content="true")
   sink.set_append_mode(false)
   inspect(sink.append_mode(), content="false")
   sink.set_auto_flush(false)
@@ -163,10 +164,12 @@ test "file sink setters update auto flush and rotation state" {
   inspect(policy.append, content="false")
   inspect(policy.auto_flush, content="false")
   inspect(policy.rotation is None, content="true")
+  inspect(sink.policy_matches_default(), content="false")
   sink.reset_policy()
   inspect(sink.append_mode(), content="true")
   inspect(sink.auto_flush_enabled(), content="true")
   inspect(sink.rotation_config() is None, content="true")
+  inspect(sink.policy_matches_default(), content="true")
 }
 
 test "file sink reset policy restores configured defaults" {
@@ -182,9 +185,11 @@ test "file sink reset policy restores configured defaults" {
   let default_policy = sink.default_policy()
   inspect(default_policy.append, content="false")
   inspect(default_policy.auto_flush, content="false")
+  inspect(sink.policy_matches_default(), content="false")
   sink.reset_policy()
   inspect(sink.append_mode(), content="false")
   inspect(sink.auto_flush_enabled(), content="false")
+  inspect(sink.policy_matches_default(), content="true")
   match sink.rotation_config() {
     Some(rotation) => {
       inspect(rotation.max_bytes, content="24")
@@ -217,6 +222,7 @@ test "file sink set policy applies bundled runtime policy" {
   inspect(default_policy.append, content="true")
   inspect(default_policy.auto_flush, content="true")
   inspect(default_policy.rotation is None, content="true")
+  inspect(sink.policy_matches_default(), content="false")
 }
 
 test "file sink tracks rotation failures on unavailable backend" {

bitlogger/README.mbt.md

@@ -243,6 +243,7 @@ test {
 - `rotation_enabled()` and `rotation_config()` expose whether rotation is active and which settings are currently applied / `rotation_enabled()` 与 `rotation_config()` 可读取 rotation 是否启用及当前配置参数
 - `state()` exposes a single file-sink snapshot including path, availability, append policy, auto-flush, rotation config, and failure counters / `state()` 可一次性读取包含 path、availability、append、auto-flush、rotation 配置与失败计数的 file sink 快照
 - `policy()` and `default_policy()` expose the current runtime policy and the sink's original defaults separately / `policy()` 与 `default_policy()` 可分别读取当前运行期策略与 sink 初始默认策略
+- `policy_matches_default()` explicitly tells whether the current runtime policy has drifted from the defaults / `policy_matches_default()` 可显式判断当前运行期策略是否已偏离默认策略
 - `set_policy(...)` applies append, auto-flush, and rotation as a bundled runtime update / `set_policy(...)` 可将 append、auto-flush、rotation 作为一组运行期策略一次性写回
 - `reset_failure_counters()` clears the open/write/flush/rotation counters after diagnostics or recovery / `reset_failure_counters()` 可在排障或恢复后清空 open/write/flush/rotation 失败计数
 - `reset_policy()` restores append, auto-flush, and rotation back to the sink's original defaults / `reset_policy()` 可将 append、auto-flush、rotation 恢复到 sink 初始默认策略
@@ -252,6 +253,7 @@ test {
 - `ConfiguredLogger` also forwards file reopen, flush, close, append-mode, path, auto-flush, rotation-config, state snapshot, append setter, policy setter, and failure-counter helpers for config-built file sinks / `ConfiguredLogger` 也会为配置生成的 file sink 转发 reopen、flush、close、append-mode、path、auto-flush、rotation 配置、state 快照、append setter、策略 setter 与失败计数访问器
 - `ConfiguredLogger::file_runtime_state()` also reports whether a file sink is queue-wrapped and exposes the outer queue pending/drop counters together with the inner file snapshot / `ConfiguredLogger::file_runtime_state()` 还可报告 file sink 是否被 queue 包装，并将外层 queue 的 pending/drop 计数与内层 file 快照一起返回
 - `ConfiguredLogger::file_policy()` and `ConfiguredLogger::file_default_policy()` also expose current runtime policy and initial config policy separately / `ConfiguredLogger::file_policy()` 与 `ConfiguredLogger::file_default_policy()` 也可分别读取当前运行期策略与初始配置策略
+- `ConfiguredLogger::file_policy_matches_default()` also tells whether the current runtime file policy has drifted from the default config / `ConfiguredLogger::file_policy_matches_default()` 也可显式判断当前运行期 file 策略是否已偏离默认配置
 - `ConfiguredLogger::file_set_policy()` also applies a bundled runtime file policy through the config-built control surface / `ConfiguredLogger::file_set_policy()` 也可通过配置式控制面一次性写回 bundled file 策略
 - `ConfiguredLogger::file_reset_failure_counters()` also clears file failure counters through the config-built control surface / `ConfiguredLogger::file_reset_failure_counters()` 也可通过配置式控制面清空 file 失败计数
 - `ConfiguredLogger::file_reset_policy()` also restores runtime file policy back to the initial config values / `ConfiguredLogger::file_reset_policy()` 也可将运行期 file 策略恢复到初始配置值

bitlogger/config.mbt

@@ -528,6 +528,14 @@ pub fn RuntimeSink::file_default_policy(self : RuntimeSink) -> FileSinkPolicy {
   }
 }
 
+pub fn RuntimeSink::file_policy_matches_default(self : RuntimeSink) -> Bool {
+  match self {
+    File(sink) => sink.policy_matches_default()
+    QueuedFile(sink) => sink.sink.policy_matches_default()
+    _ => false
+  }
+}
+
 pub fn RuntimeSink::file_state(self : RuntimeSink) -> FileSinkState {
   match self {
     File(sink) => sink.state()
@@ -686,6 +694,10 @@ pub fn ConfiguredLogger::file_default_policy(self : ConfiguredLogger) -> FileSin
   self.sink.file_default_policy()
 }
 
+pub fn ConfiguredLogger::file_policy_matches_default(self : ConfiguredLogger) -> Bool {
+  self.sink.file_policy_matches_default()
+}
+
 pub fn ConfiguredLogger::file_state(self : ConfiguredLogger) -> FileSinkState {
   self.sink.file_state()
 }

bitlogger/sinks.mbt

@@ -268,6 +268,22 @@ pub fn FileSink::default_policy(self : FileSink) -> FileSinkPolicy {
   )
 }
 
+pub fn FileSink::policy_matches_default(self : FileSink) -> Bool {
+  let current = self.policy()
+  let default = self.default_policy()
+  current.append == default.append &&
+  current.auto_flush == default.auto_flush &&
+  policy_rotation_equals_internal(current.rotation, default.rotation)
+}
+
+fn policy_rotation_equals_internal(left : FileRotation?, right : FileRotation?) -> Bool {
+  match (left, right) {
+    (None, None) => true
+    (Some(a), Some(b)) => a.max_bytes == b.max_bytes && a.max_backups == b.max_backups
+    _ => false
+  }
+}
+
 pub fn FileSink::state(self : FileSink) -> FileSinkState {
   {
     path: self.path,