Abseil LTS branch, May 2025, Patch 2 (#2009)

* Fix sign-extension issue in absl::HexStringToBytes()

Author: derekmauro

MODULE.bazel

@@ -16,7 +16,7 @@
 
 module(
     name = "abseil-cpp",
-    version = "20250512.1",
+    version = "20250512.2",
     compatibility_level = 1,
 )
 

absl/base/config.h

@@ -118,7 +118,7 @@
 // LTS releases can be obtained from
 // https://github.com/abseil/abseil-cpp/releases.
 #define ABSL_LTS_RELEASE_VERSION 20250512
-#define ABSL_LTS_RELEASE_PATCH_LEVEL 1
+#define ABSL_LTS_RELEASE_PATCH_LEVEL 2
 
 // Helper macro to convert a CPP variable to a string literal.
 #define ABSL_INTERNAL_DO_TOKEN_STR(x) #x

absl/strings/escaping.cc

@@ -827,7 +827,7 @@ bool Base64UnescapeInternal(const char* absl_nullable src, size_t slen,
 }
 
 /* clang-format off */
-constexpr std::array<char, 256> kHexValueLenient = {
+constexpr std::array<uint8_t, 256> kHexValueLenient = {
     0,  0,  0,  0,  0,  0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0,  0,  0,  0,  0,  0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0,  0,  0,  0,  0,  0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
@@ -846,7 +846,7 @@ constexpr std::array<char, 256> kHexValueLenient = {
     0,  0,  0,  0,  0,  0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 };
 
-constexpr std::array<signed char, 256> kHexValueStrict = {
+constexpr std::array<int8_t, 256> kHexValueStrict = {
     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
@@ -874,7 +874,7 @@ void HexStringToBytesInternal(const char* absl_nullable from, T to,
                               size_t num) {
   for (size_t i = 0; i < num; i++) {
     to[i] = static_cast<char>(kHexValueLenient[from[i * 2] & 0xFF] << 4) +
-            (kHexValueLenient[from[i * 2 + 1] & 0xFF]);
+            static_cast<char>(kHexValueLenient[from[i * 2 + 1] & 0xFF]);
   }
 }
 
@@ -970,8 +970,10 @@ bool HexStringToBytes(absl::string_view hex, std::string* absl_nonnull bytes) {
   auto hex_p = hex.cbegin();
   for (std::string::iterator bin_p = output.begin(); bin_p != output.end();
        ++bin_p) {
-    int h1 = absl::kHexValueStrict[static_cast<size_t>(*hex_p++)];
-    int h2 = absl::kHexValueStrict[static_cast<size_t>(*hex_p++)];
+    int h1 = absl::kHexValueStrict[static_cast<size_t>(
+        static_cast<uint8_t>(*hex_p++))];
+    int h2 = absl::kHexValueStrict[static_cast<size_t>(
+        static_cast<uint8_t>(*hex_p++))];
     if (h1 == -1 || h2 == -1) {
       output.resize(static_cast<size_t>(bin_p - output.begin()));
       return false;

absl/strings/escaping_test.cc

@@ -733,6 +733,10 @@ TEST(Escaping, HexStringToBytesBackToHex) {
   bytes = "abc";
   EXPECT_TRUE(absl::HexStringToBytes("", &bytes));
   EXPECT_EQ("", bytes);  // Results in empty output.
+
+  // Ensure there is no sign extension bug on a signed char.
+  hex.assign("\xC8" "b", 2);
+  EXPECT_FALSE(absl::HexStringToBytes(hex, &bytes));
 }
 
 TEST(HexAndBack, HexStringToBytes_and_BytesToHexString) {