Merge #255: fix: use unsigned char cast and sizeof in LogEscape escape sequence

554a481 fix: use unsigned char cast and sizeof in LogEscape escape sequence (Mangoostaa)

Pull request description:

  Found a small correctness issue in LogEscape():

  - When char is signed (common on x86_64 Linux), negative byte values
  (e.g. 0xFF = -1) were being printed as ffffffff instead of ff.

  - This fixes it by casting to unsigned char before %02x.

  - Also changed the hardcoded 4 to sizeof(escape) so the code doesn't
  break silently if someone increases the buffer size later.

  No performance impact, just safer and more portable.

ACKs for top commit:
  ryanofsky:
    Code review ACK 554a481. Signed fix and sizeof cleanup both makes sense. Nice catch!

Tree-SHA512: 5a19b3caf4b371a363ed7f5151871e306c91c8e4bf180e7df530a562298b924c8a8e213d82069e580dc9d474bcddc7455d842849d7b50152d6eb29aa1f6e97c0

Author: ryanofsky

src/mp/util.cpp

@@ -102,7 +102,7 @@ std::string LogEscape(const kj::StringTree& string, size_t max_size)
                 result.append("\\\\");
             } else if (c < 0x20 || c > 0x7e) {
                 char escape[4];
-                snprintf(escape, 4, "\\%02x", c);
+                snprintf(escape, sizeof(escape), "\\%02x", static_cast<unsigned char>(c));
                 result.append(escape);
             } else {
                 result.push_back(c);