updates, errors: Add a doc comment

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/src/error.rs b/src/error.rs
index 22d9f97e76f0209a97e2c4d7d806f0cc6375db2b..04e4978fea43593d5617491a5a41c9641f5af17e 100644 (file)
--- a/src/error.rs
+++ b/src/error.rs
@@ -79,6 +79,12 @@ impl From<InternalError> for SpecError {
 pub enum ApiPieceOpError {
   ReportViaResponse(#[from] OnlineError),
   ReportViaUpdate(#[from] PieceOpError),
+
+  /// This error is always generated in the context of a piece
+  /// operation by a particular client.  It corresponds roughly to a
+  /// PieceUpdateFromOp for other clients of (Unpredicable,
+  /// PieceUpdateOp::Modify, ..).
+  /// For this client it is that but also an error report.
   PartiallyProcessed(PieceOpError, Vec<LogEntry>),
 }
 display_as_debug!(ApiPieceOpError);