Abseil LTS branch, Jan 2026, Patch 1 (#2007)

* Fix sign-extension issue in absl::HexStringToBytes()
* Restrict MSVC CRC32 intrinsics to x64.

Author: derekmauro

MODULE.bazel

@@ -16,7 +16,7 @@
 
 module(
     name = "abseil-cpp",
-    version = "20260107.0",
+    version = "20260107.1",
     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 20260107
-#define ABSL_LTS_RELEASE_PATCH_LEVEL 0
+#define ABSL_LTS_RELEASE_PATCH_LEVEL 1
 
 // Helper macro to convert a CPP variable to a string literal.
 #define ABSL_INTERNAL_DO_TOKEN_STR(x) #x

absl/hash/internal/hash.h

@@ -104,7 +104,10 @@
 #define ABSL_HASH_INTERNAL_CRC32_U32 _mm_crc32_u32
 #define ABSL_HASH_INTERNAL_CRC32_U8 _mm_crc32_u8
 
-#elif defined(_MSC_VER) && !defined(__clang__) && defined(__AVX__)
+// 32-bit builds with AVX do not have _mm_crc32_u64, so the _M_X64 condition is
+// necessary.
+#elif defined(_MSC_VER) && !defined(__clang__) && defined(__AVX__) && \
+    defined(_M_X64)
 
 // MSVC AVX (/arch:AVX) implies SSE 4.2.
 #include <intrin.h>

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]);
   }
 }
 
@@ -992,8 +992,10 @@ bool HexStringToBytes(absl::string_view hex, std::string* absl_nonnull bytes) {
       output, num_bytes, [hex](char* buf, size_t buf_size) {
         auto hex_p = hex.cbegin();
         for (size_t i = 0; i < buf_size; ++i) {
-          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) {
             return size_t{0};
           }

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) {