Merge bitcoin/bitcoin#27747: rpc: Use 'byte'/'bytes' for bech32(m) validation error message

3d0a5c37e9ccedfa4ecfaa48eeeca1ada5b4eec1 use 'byte'/'bytes' for bech32(m) validation error (Reese Russell)

Pull request description:

  This PR rectifies a linguistic inconsistency found in merged PR [27727](https://github.com/bitcoin/bitcoin/pull/27727). It addresses the improper usage of the term 'byte' in error reports. As it stands, PR [27727](https://github.com/bitcoin/bitcoin/pull/27727) exclusively utilizes 'byte' in error messages, regardless of the context, as demonstrated below:

  Currently: ```Invalid Bech32 v0 address program size (16 byte), per BIP141```

  This modification enhances the accuracy of error reporting in most scenarios users are likely to encounter by checking for a plural or singular number of bytes.

  This PR

  **16 Bytes program size error** :

  ```
  (
      "BC1QR508D6QEJXTDG4Y5R3ZARVARYV98GJ9P",
      "Invalid Bech32 v0 address program size (16 bytes), per BIP141",
      [],
  )
  ```

  **1 Byte program size error**

  ```
  (
      "bc1pw5dgrnzv",
      "Invalid Bech32 address program size (1 byte)",
      []
  ),
  ```
  Thank you

ACKs for top commit:
  MarcoFalke:
    lgtm ACK 3d0a5c37e9ccedfa4ecfaa48eeeca1ada5b4eec1

Tree-SHA512: 55069194a6a33a37559cf14b59b6ac05b1160f57f14d1415aef8e76c916c7c7f343310916ae85b3fa895937802449c1dddb2f653340d0f39203f06aee10f6fce

1 files changed, 5 insertions, 2 deletions

diff --git a/src/key_io.cpp b/src/key_io.cpp
index 33499b0d23..454a96df5e 100644
--- a/src/key_io.cpp
+++ b/src/key_io.cpp
@@ -146,6 +146,9 @@ CTxDestination DecodeDestination(const std::string& str, const CChainParams& par
         // The rest of the symbols are converted witness program bytes.
         data.reserve(((dec.data.size() - 1) * 5) / 8);
         if (ConvertBits<5, 8, false>([&](unsigned char c) { data.push_back(c); }, dec.data.begin() + 1, dec.data.end())) {
+
+            std::string_view byte_str{data.size() == 1 ? "byte" : "bytes"};
+
             if (version == 0) {
                 {
                     WitnessV0KeyHash keyid;
@@ -162,7 +165,7 @@ CTxDestination DecodeDestination(const std::string& str, const CChainParams& par
                     }
                 }
 
-                error_str = strprintf("Invalid Bech32 v0 address program size (%s byte), per BIP141", data.size());
+                error_str = strprintf("Invalid Bech32 v0 address program size (%d %s), per BIP141", data.size(), byte_str);
                 return CNoDestination();
             }
 
@@ -179,7 +182,7 @@ CTxDestination DecodeDestination(const std::string& str, const CChainParams& par
             }
 
             if (data.size() < 2 || data.size() > BECH32_WITNESS_PROG_MAX_LEN) {
-                error_str = strprintf("Invalid Bech32 address program size (%s byte)", data.size());
+                error_str = strprintf("Invalid Bech32 address program size (%d %s)", data.size(), byte_str);
                 return CNoDestination();
             }