4 files changed, 15 insertions, 14 deletions
diff --git a/src/test/fuzz/base_encode_decode.cpp b/src/test/fuzz/base_encode_decode.cpp
index 196410e29c..48356065b0 100644
--- a/src/test/fuzz/base_encode_decode.cpp
+++ b/src/test/fuzz/base_encode_decode.cpp
@@ -26,7 +26,7 @@ FUZZ_TARGET_INIT(base_encode_decode, initialize_base_encode_decode)
     std::vector<unsigned char> decoded;
     if (DecodeBase58(random_encoded_string, decoded, 100)) {
         const std::string encoded_string = EncodeBase58(decoded);
-        assert(encoded_string == TrimString(encoded_string));
+        assert(encoded_string == TrimStringView(encoded_string));
         assert(ToLower(encoded_string) == ToLower(TrimString(random_encoded_string)));
     }
 
@@ -36,17 +36,16 @@ FUZZ_TARGET_INIT(base_encode_decode, initialize_base_encode_decode)
         assert(ToLower(encoded_string) == ToLower(TrimString(random_encoded_string)));
     }
 
-    bool pf_invalid;
-    std::string decoded_string = DecodeBase32(random_encoded_string, &pf_invalid);
-    if (!pf_invalid) {
-        const std::string encoded_string = EncodeBase32(decoded_string);
-        assert(encoded_string == TrimString(encoded_string));
+    auto result = DecodeBase32(random_encoded_string);
+    if (result) {
+        const std::string encoded_string = EncodeBase32(*result);
+        assert(encoded_string == TrimStringView(encoded_string));
         assert(ToLower(encoded_string) == ToLower(TrimString(random_encoded_string)));
     }
 
-    decoded_string = DecodeBase64(random_encoded_string, &pf_invalid);
-    if (!pf_invalid) {
-        const std::string encoded_string = EncodeBase64(decoded_string);
+    result = DecodeBase64(random_encoded_string);
+    if (result) {
+        const std::string encoded_string = EncodeBase64(*result);
         assert(encoded_string == TrimString(encoded_string));
         assert(ToLower(encoded_string) == ToLower(TrimString(random_encoded_string)));
     }
diff --git a/src/test/fuzz/http_request.cpp b/src/test/fuzz/http_request.cpp
index 916e90e986..0fe18abaa9 100644
--- a/src/test/fuzz/http_request.cpp
+++ b/src/test/fuzz/http_request.cpp
@@ -39,7 +39,7 @@ FUZZ_TARGET(http_request)
     // and is a consequence of our hacky but necessary use of the internal function evhttp_parse_firstline_ in
     // this fuzzing harness. The workaround is not aesthetically pleasing, but it successfully avoids the troublesome
     // code path. " http:// HTTP/1.1\n" was a crashing input prior to this workaround.
-    const std::string http_buffer_str = ToLower({http_buffer.begin(), http_buffer.end()});
+    const std::string http_buffer_str = ToLower(std::string{http_buffer.begin(), http_buffer.end()});
     if (http_buffer_str.find(" http://") != std::string::npos || http_buffer_str.find(" https://") != std::string::npos ||
         evhttp_parse_firstline_(evreq, evbuf) != 1 || evhttp_parse_headers_(evreq, evbuf) != 1) {
         evbuffer_free(evbuf);
diff --git a/src/test/fuzz/psbt.cpp b/src/test/fuzz/psbt.cpp
index 669688a80d..baa64bba0f 100644
--- a/src/test/fuzz/psbt.cpp
+++ b/src/test/fuzz/psbt.cpp
@@ -32,7 +32,8 @@ FUZZ_TARGET_INIT(psbt, initialize_psbt)
     FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
     PartiallySignedTransaction psbt_mut;
     std::string error;
-    if (!DecodeRawPSBT(psbt_mut, fuzzed_data_provider.ConsumeRandomLengthString(), error)) {
+    auto str = fuzzed_data_provider.ConsumeRandomLengthString();
+    if (!DecodeRawPSBT(psbt_mut, MakeByteSpan(str), error)) {
         return;
     }
     const PartiallySignedTransaction psbt = psbt_mut;
@@ -79,7 +80,8 @@ FUZZ_TARGET_INIT(psbt, initialize_psbt)
     }
 
     PartiallySignedTransaction psbt_merge;
-    if (!DecodeRawPSBT(psbt_merge, fuzzed_data_provider.ConsumeRandomLengthString(), error)) {
+    str = fuzzed_data_provider.ConsumeRandomLengthString();
+    if (!DecodeRawPSBT(psbt_merge, MakeByteSpan(str), error)) {
         psbt_merge = psbt;
     }
     psbt_mut = psbt;
diff --git a/src/test/fuzz/string.cpp b/src/test/fuzz/string.cpp
index b4876d427f..e6064d19b6 100644
--- a/src/test/fuzz/string.cpp
+++ b/src/test/fuzz/string.cpp
@@ -42,7 +42,7 @@ bool LegacyParsePrechecks(const std::string& str)
         return false;
     if (str.size() >= 1 && (IsSpace(str[0]) || IsSpace(str[str.size() - 1]))) // No padding allowed
         return false;
-    if (!ValidAsCString(str)) // No embedded NUL characters allowed
+    if (!ContainsNoNUL(str)) // No embedded NUL characters allowed
         return false;
     return true;
 }
@@ -188,7 +188,7 @@ FUZZ_TARGET(string)
     (void)TrimString(random_string_1);
     (void)TrimString(random_string_1, random_string_2);
     (void)urlDecode(random_string_1);
-    (void)ValidAsCString(random_string_1);
+    (void)ContainsNoNUL(random_string_1);
     (void)_(random_string_1.c_str());
     try {
         throw scriptnum_error{random_string_1};