Report encoding type in bech32 error message

2 files changed, 11 insertions, 5 deletions

diff --git a/src/bech32.cpp b/src/bech32.cpp
index ec69965d07..7585ee944c 100644
--- a/src/bech32.cpp
+++ b/src/bech32.cpp
@@ -7,6 +7,7 @@
 #include <util/vector.h>
 
 #include <assert.h>
+#include <optional>
 
 namespace bech32
 {
@@ -539,6 +540,7 @@ std::string LocateErrors(const std::string& str, std::vector<int>& error_locatio
 
     // We attempt error detection with both bech32 and bech32m, and choose the one with the fewest errors
     // We can't simply use the segwit version, because that may be one of the errors
+    std::optional<Encoding> error_encoding;
     for (Encoding encoding : {Encoding::BECH32, Encoding::BECH32M}) {
         std::vector<int> possible_errors;
         // Recall that (ExpandHRP(hrp) ++ values) is interpreted as a list of coefficients of a polynomial
@@ -657,9 +659,13 @@ std::string LocateErrors(const std::string& str, std::vector<int>& error_locatio
 
         if (error_locations.empty() || (!possible_errors.empty() && possible_errors.size() < error_locations.size())) {
             error_locations = std::move(possible_errors);
+            if (!error_locations.empty()) error_encoding = encoding;
         }
     }
-    return "Invalid checksum";
+    return error_encoding == Encoding::BECH32M ? "Invalid Bech32m checksum"
+            : error_encoding == Encoding::BECH32 ? "Invalid Bech32 checksum"
+            : "Invalid checksum";
+
 }
 
 } // namespace bech32
diff --git a/src/test/bech32_tests.cpp b/src/test/bech32_tests.cpp
index 7601ead5b8..5d851a9735 100644
--- a/src/test/bech32_tests.cpp
+++ b/src/test/bech32_tests.cpp
@@ -87,8 +87,8 @@ BOOST_AUTO_TEST_CASE(bech32_testvectors_invalid)
         {"Invalid separator position", {0}},
         {"Invalid character or mixed case", {3, 4, 5, 7}},
         {"Invalid character or mixed case", {3}},
-        {"Invalid checksum", {11}},
-        {"Invalid checksum", {9, 16}},
+        {"Invalid Bech32 checksum", {11}},
+        {"Invalid Bech32 checksum", {9, 16}},
     };
     static_assert(std::size(CASES) == std::size(ERRORS), "Bech32 CASES and ERRORS should have the same length");
 
@@ -140,8 +140,8 @@ BOOST_AUTO_TEST_CASE(bech32m_testvectors_invalid)
         {"Invalid checksum", {}},
         {"Invalid separator position", {0}},
         {"Invalid separator position", {0}},
-        {"Invalid checksum", {21}},
-        {"Invalid checksum", {13, 32}},
+        {"Invalid Bech32m checksum", {21}},
+        {"Invalid Bech32m checksum", {13, 32}},
     };
     static_assert(std::size(CASES) == std::size(ERRORS), "Bech32m CASES and ERRORS should have the same length");