From 170121cdf6fb1b677be676ee24643437ecfb064f Mon Sep 17 00:00:00 2001
From: Richard Dodd <richard.o.dodd@gmail.com>
Date: Sat, 21 Aug 2021 22:36:23 +0100
Subject: [PATCH 1/3] Add defmt support for mpsc errors.

---
 embassy/src/util/mpsc.rs | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/embassy/src/util/mpsc.rs b/embassy/src/util/mpsc.rs
index bad1058a..b9a95d6a 100644
--- a/embassy/src/util/mpsc.rs
+++ b/embassy/src/util/mpsc.rs
@@ -386,6 +386,7 @@ where
 ///
 /// [`try_recv`]: super::Receiver::try_recv
 #[derive(PartialEq, Eq, Clone, Copy, Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum TryRecvError {
     /// A message could not be received because the channel is empty.
     Empty,
@@ -404,6 +405,14 @@ impl<T> fmt::Display for SendError<T> {
     }
 }
 
+#[cfg(feature = "defmt")]
+impl<T> defmt::Format for SendError<T> {
+    fn format(&self, fmt: defmt::Formatter<'_>) {
+        defmt::write!(fmt, "channel closed")
+    }
+}
+
+
 /// This enumeration is the list of the possible error outcomes for the
 /// [try_send](super::Sender::try_send) method.
 #[derive(Debug)]
@@ -430,6 +439,20 @@ impl<T> fmt::Display for TrySendError<T> {
     }
 }
 
+#[cfg(feature = "defmt")]
+impl<T> defmt::Format for TrySendError<T> {
+    fn format(&self, fmt: defmt::Formatter<'_>) {
+        defmt::write!(
+            fmt,
+            "{}",
+            match self {
+                TrySendError::Full(..) => "no available capacity",
+                TrySendError::Closed(..) => "channel closed",
+            }
+        )
+    }
+}
+
 struct ChannelState<T, const N: usize> {
     buf: [MaybeUninit<UnsafeCell<T>>; N],
     read_pos: usize,

From 4d3c07f71b9402bf1735b7f81035d90e6de7a28e Mon Sep 17 00:00:00 2001
From: Richard Dodd <richard.o.dodd@gmail.com>
Date: Sat, 21 Aug 2021 22:38:02 +0100
Subject: [PATCH 2/3] Fix fmt

---
 embassy/src/util/mpsc.rs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/embassy/src/util/mpsc.rs b/embassy/src/util/mpsc.rs
index b9a95d6a..364b98aa 100644
--- a/embassy/src/util/mpsc.rs
+++ b/embassy/src/util/mpsc.rs
@@ -412,7 +412,6 @@ impl<T> defmt::Format for SendError<T> {
     }
 }
 
-
 /// This enumeration is the list of the possible error outcomes for the
 /// [try_send](super::Sender::try_send) method.
 #[derive(Debug)]

From 7ca745a5c0bf8cdee578ee1108e78b73b7161f4e Mon Sep 17 00:00:00 2001
From: Richard Dodd <richard.o.dodd@gmail.com>
Date: Sun, 22 Aug 2021 00:11:19 +0100
Subject: [PATCH 3/3] Refactor to allow defmt to intern strings.

---
 embassy/src/util/mpsc.rs | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/embassy/src/util/mpsc.rs b/embassy/src/util/mpsc.rs
index 364b98aa..4257ecd4 100644
--- a/embassy/src/util/mpsc.rs
+++ b/embassy/src/util/mpsc.rs
@@ -441,14 +441,10 @@ impl<T> fmt::Display for TrySendError<T> {
 #[cfg(feature = "defmt")]
 impl<T> defmt::Format for TrySendError<T> {
     fn format(&self, fmt: defmt::Formatter<'_>) {
-        defmt::write!(
-            fmt,
-            "{}",
-            match self {
-                TrySendError::Full(..) => "no available capacity",
-                TrySendError::Closed(..) => "channel closed",
-            }
-        )
+        match self {
+            TrySendError::Full(..) => defmt::write!(fmt, "no available capacity"),
+            TrySendError::Closed(..) => defmt::write!(fmt, "channel closed"),
+        }
     }
 }