chore(heal): remove seven dead error variants

heal::Error carried six variants with zero construction and zero match sites (ConfigurationError, NotFound, TaskAlreadyExists, ManagerNotRunning, EventProcessingFailed, ProgressTrackingFailed) plus IO(String), which was never constructed either — its only appearances were two or-pattern match arms that could never fire (task.rs's demotion match and the recoverability classifier). All seven are deleted and the two or-patterns lose their dead alternative.

Config(String) stays (live, four construction sites); Io(std::io::Error) stays; the retry classifier's behavior is untouched per the issue constraint — removing an arm that can never match is not a classification change.

Ref rustfs/backlog#1831 (PR3).

crates/heal/src/error.rs

@@ -34,36 +34,21 @@ pub enum Error {
     #[error("Configuration error: {0}")]
     Config(String),
 
-    #[error("Heal configuration error: {message}")]
-    ConfigurationError { message: String },
-
     #[error("Other error: {0}")]
     Other(String),
 
     #[error("Serialization error: {0}")]
     Serialization(String),
 
-    #[error("IO error: {0}")]
-    IO(String),
-
-    #[error("Not found: {0}")]
-    NotFound(String),
-
     #[error("Invalid checkpoint: {0}")]
     InvalidCheckpoint(String),
 
     #[error("Heal task not found: {task_id}")]
     TaskNotFound { task_id: String },
 
-    #[error("Heal task already exists: {task_id}")]
-    TaskAlreadyExists { task_id: String },
-
     #[error("Invalid heal client token")]
     InvalidClientToken,
 
-    #[error("Heal manager is not running")]
-    ManagerNotRunning,
-
     #[error("Heal task execution failed: {message}")]
     TaskExecutionFailed { message: String },
 
@@ -78,12 +63,6 @@ pub enum Error {
 
     #[error("Heal task timeout")]
     TaskTimeout,
-
-    #[error("Heal event processing failed: {message}")]
-    EventProcessingFailed { message: String },
-
-    #[error("Heal progress tracking failed: {message}")]
-    ProgressTrackingFailed { message: String },
 }
 
 /// A specialized Result type for heal operations
@@ -129,9 +108,7 @@ impl Error {
                         | DiskError::FaultyDisk
                 ) || is_recoverable_heal_error_message(&err.to_string())
             }
-            Error::TaskExecutionFailed { message } | Error::IO(message) | Error::Other(message) => {
-                is_recoverable_heal_error_message(message)
-            }
+            Error::TaskExecutionFailed { message } | Error::Other(message) => is_recoverable_heal_error_message(message),
             Error::Io(err) => is_recoverable_heal_error_message(&err.to_string()),
             _ => false,
         }

crates/heal/src/heal/task.rs

@@ -597,7 +597,7 @@ impl HealTask {
                 | EcstoreError::ObjectNotFound(_, _)
                 | EcstoreError::VersionNotFound(_, _, _),
             ) => true,
-            Error::Other(message) | Error::IO(message) => {
+            Error::Other(message) => {
                 message.contains("File not found")
                     || message.contains("file not found")
                     || message.contains("File version not found")