From a4a4b19f2129b48970b2b61a0aa85d529d39f408 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Tue, 24 Jan 2023 13:48:39 +0000
Subject: [PATCH] tor-bytes: Implement conversion from EncodeError to Bug

---
 crates/tor-bytes/semver.md  |  1 +
 crates/tor-bytes/src/err.rs | 17 ++++++++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 crates/tor-bytes/semver.md

diff --git a/crates/tor-bytes/semver.md b/crates/tor-bytes/semver.md
new file mode 100644
index 000000000..a9f4f688d
--- /dev/null
+++ b/crates/tor-bytes/semver.md
@@ -0,0 +1 @@
+ADDED: EncodeError::always_bug method to turn an EcodeError into a Bug
diff --git a/crates/tor-bytes/src/err.rs b/crates/tor-bytes/src/err.rs
index 899b0fab6..e35097a48 100644
--- a/crates/tor-bytes/src/err.rs
+++ b/crates/tor-bytes/src/err.rs
@@ -1,6 +1,7 @@
 //! Internal: Declare an Error type for tor-bytes
 
 use thiserror::Error;
+use tor_error::{into_internal, Bug};
 
 /// Error type for decoding Tor objects from bytes.
 //
@@ -62,5 +63,19 @@ pub enum EncodeError {
     /// We use this variant instead of calling assert() and expect() and
     /// unwrap() from within encoding implementations.
     #[error("Internal error")]
-    Bug(#[from] tor_error::Bug),
+    Bug(#[from] Bug),
+}
+
+impl EncodeError {
+    /// Converts this error into a [`Bug`]
+    ///
+    /// Use when any encoding error is a bug.
+    //
+    // TODO: should this be a `From` impl or would that be too error-prone?
+    pub fn always_bug(self) -> Bug {
+        match self {
+            EncodeError::Bug(bug) => bug,
+            EncodeError::BadLengthValue => into_internal!("EncodingError")(self),
+        }
+    }
 }