From 4547118bac407aa5d0942bf4b9c8c73952dcdb46 Mon Sep 17 00:00:00 2001
From: Marshall Pierce <marshall@mpierce.org>
Date: Thu, 24 Sep 2020 16:11:30 -0600
Subject: [PATCH] Add a note for InvalidLength explaining that trailing
 whitespace is a common cause

---
 src/decode.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/decode.rs b/src/decode.rs
index 716fce73..20848a02 100644
--- a/src/decode.rs
+++ b/src/decode.rs
@@ -29,6 +29,7 @@ pub enum DecodeError {
     /// An invalid byte was found in the input. The offset and offending byte are provided.
     InvalidByte(usize, u8),
     /// The length of the input is invalid.
+    /// A typical cause of this is stray trailing whitespace or other separator bytes.
     InvalidLength,
     /// The last non-padding input symbol's encoded 6 bits have nonzero bits that will be discarded.
     /// This is indicative of corrupted or truncated Base64.
@@ -43,7 +44,7 @@ impl fmt::Display for DecodeError {
             DecodeError::InvalidByte(index, byte) => {
                 write!(f, "Invalid byte {}, offset {}.", byte, index)
             }
-            DecodeError::InvalidLength => write!(f, "Encoded text cannot have a 6-bit remainder."),
+            DecodeError::InvalidLength => write!(f, "Encoded text cannot have a 6-bit remainder. Trailing whitespace or other bytes?"),
             DecodeError::InvalidLastSymbol(index, byte) => {
                 write!(f, "Invalid last symbol {}, offset {}.", byte, index)
             }