diff --git a/devel/string_theory/Makefile b/devel/string_theory/Makefile
index c5bd1ba7d08d..ff65c54d7e4f 100644
--- a/devel/string_theory/Makefile
+++ b/devel/string_theory/Makefile
@@ -1,23 +1,33 @@
 PORTNAME=	string_theory
-PORTVERSION=	3.8
+PORTVERSION=	3.9
 CATEGORIES=	devel
-MASTER_SITES=	https://github.com/zrax/string_theory/releases/download/${PORTVERSION}/
 
 MAINTAINER=	sunpoet@FreeBSD.org
 COMMENT=	Modern C++ library for string manipulation and storage
 WWW=		https://github.com/zrax/string_theory
 
 LICENSE=	MIT
 LICENSE_FILE=	${WRKSRC}/LICENSE
 
-USES=		cmake:testing compiler:c++20-lang
+TEST_DEPENDS=	googletest>=0:devel/googletest
 
-CMAKE_OFF=	ST_BUILD_PROFILE_TEST \
-		ST_BUILD_TESTS \
-		ST_BUILD_TEST_COVERAGE
+USES=		cmake:testing compiler:c++20-lang localbase:ldflags
+
+CMAKE_OFF=	ST_BUILD_TEST_COVERAGE \
+		ST_BUILD_TESTS
 CMAKE_ON=	ST_ENABLE_STL_FILESYSTEM \
 		ST_ENABLE_STL_STRINGS
-CMAKE_TESTING_ON=	ST_BUILD_TESTS
+CMAKE_TESTING_OFF=	\
+		BUILD_GMOCK \
+		INSTALL_GTEST \
+		ST_BUILD_PROFILE_TEST
+CMAKE_TESTING_ON=	\
+		ST_BUILD_TEST_COVERAGE \
+		ST_BUILD_TESTS \
+		ST_USE_SYSTEM_GTEST
 NO_ARCH=	yes
 
+USE_GITHUB=	yes
+GH_ACCOUNT=	zrax
+
 .include <bsd.port.mk>
diff --git a/devel/string_theory/distinfo b/devel/string_theory/distinfo
index 355218bb2d78..28587bef31a4 100644
--- a/devel/string_theory/distinfo
+++ b/devel/string_theory/distinfo
@@ -1,3 +1,3 @@
-TIMESTAMP = 1696963431
-SHA256 (string_theory-3.8.tar.gz) = 2b43daf9424e3136327e71b70abe0b15d51427653778df7b149574ef1dfec890
-SIZE (string_theory-3.8.tar.gz) = 954929
+TIMESTAMP = 1767157579
+SHA256 (zrax-string_theory-3.9_GH0.tar.gz) = 9bb0a9697319964479f813d9c61e3c5a1f57f7e8a5bc6db14cba7489addc3f49
+SIZE (zrax-string_theory-3.9_GH0.tar.gz) = 68952
diff --git a/devel/string_theory/files/patch-test b/devel/string_theory/files/patch-test
new file mode 100644
index 000000000000..5c431ea7e4db
--- /dev/null
+++ b/devel/string_theory/files/patch-test
@@ -0,0 +1,44 @@
+--- test/test_buffer.cpp.orig	2025-01-10 20:58:36 UTC
++++ test/test_buffer.cpp
+@@ -310,41 +310,6 @@ TEST(char_buffer, move)
+     EXPECT_EQ(24U, wdest2.size());
+ }
+ 
+-#if (defined(__clang__) && ((__clang_major__ > 3) || (__clang_major__ == 3 && __clang_minor__ > 5))) \
+-    || (defined(__GNUC__) && (__GNUC__ >= 13))
+-#   pragma GCC diagnostic push
+-#   pragma GCC diagnostic ignored "-Wself-move"
+-#   if defined(__clang__) && (__clang_major__ > 6)
+-#       pragma GCC diagnostic ignored "-Wself-assign-overloaded"
+-#   endif
+-#endif
+-
+-TEST(char_buffer, self_assign)
+-{
+-    // If this changes, this test may need to be updated to match
+-    ASSERT_EQ(16, ST_MAX_SSO_LENGTH);
+-
+-    ST::char_buffer sbuf;
+-    sbuf = sbuf;
+-    EXPECT_EQ(0, T_strcmp(sbuf.data(), ""));
+-
+-    ST::char_buffer shortbuf("0123456789", 10);
+-    sbuf = shortbuf;
+-    EXPECT_EQ(0, T_strcmp(sbuf.data(), "0123456789"));
+-    sbuf = sbuf;
+-    EXPECT_EQ(0, T_strcmp(sbuf.data(), "0123456789"));
+-    sbuf = std::move(sbuf);
+-    // Content not guaranteed after self-move
+-
+-    ST::char_buffer longbuf("0123456789abcdefghij", 20);
+-    sbuf = longbuf;
+-    EXPECT_EQ(0, T_strcmp(sbuf.data(), "0123456789abcdefghij"));
+-    sbuf = sbuf;
+-    EXPECT_EQ(0, T_strcmp(sbuf.data(), "0123456789abcdefghij"));
+-    sbuf = std::move(sbuf);
+-    // Content not guaranteed after self-move
+-}
+-
+ #if defined(__clang__) && ((__clang_major__ > 3) || (__clang_major__ == 3 && __clang_minor__ > 5))
+ #   pragma GCC diagnostic pop
+ #endif