Update to 2025-07-09 google3 version

* Require C++17
* Require abseil-cpp LTS 20250512
* Fix S2ShapeNestingQuery when two chains share a vertex
* Fix S2Polygon bug when intersecting polyline
* Add S2ClosestEdgeQuery::VisitClosestShapes
* Delete deprecated S2Error::text(); use message() instead
* Ensure _fp_contract_off.h is included everywhere
* Add thread annotations to SpinLock
* Convert many const vector<>&s to Span<>s
* Add noexcept to move operators
* Make some comparisons stable for sorting
* Guard against overflow in Decode functions

Author: jmr

CMakeLists.txt

@@ -19,8 +19,7 @@ endif()
 # s2geometry needs to use the same C++ standard that absl used to avoid
 # undefined symbol errors since ABSL_HAVE_STD_STRING_VIEW etc will
 # end up defined differently.  There is probably a better way to achieve
-# this than assuming what absl used.  We default to c++17, but support
-# c++14 (like abseil).
+# this than assuming what absl used.  We require at least C++17.
 # Using CACHE allows the user to override the default.
 set(CMAKE_CXX_STANDARD 17 CACHE STRING "The C++ standard to build with")
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
@@ -232,6 +231,7 @@ endif()
 target_link_libraries(
     s2
     ${OPENSSL_LIBRARIES}
+    absl::absl_vlog_is_on
     absl::base
     absl::btree
     absl::check
@@ -438,7 +438,6 @@ if(S2_ENABLE_INSTALL)
                 src/s2/base/malloc_extension.h
                 src/s2/base/port.h
                 src/s2/base/spinlock.h
-                src/s2/base/types.h
           DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/s2/base")
   install(FILES src/s2/testing/gtest_prod.h
           DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/s2/testing")

README.md

@@ -18,8 +18,9 @@ S2 documentation can be found on [s2geometry.io](http://s2geometry.io).
 
 Note that all [releases](https://github.com/google/s2geometry/releases) are
 version 0.x, so there are
-[no API or ABI stability guarantees](https://semver.org/#spec-item-4).
-Starting with 1.0 we will adhere to [SemVer](https://semver.org/).
+[no API or ABI stability guarantees](https://semver.org/#spec-item-4). Starting
+with 1.0 we will adhere to [SemVer](https://semver.org/) and follow the
+[Google OSS breaking change policy](https://opensource.google/documentation/policies/library-breaking-change)
 
 The Python API is particularly unstable, and it is planned that the SWIGged
 API will be replaced by a pybind11 version with more Pythonic names and more
@@ -49,8 +50,12 @@ This issue may require revision of boringssl or exactfloat.
 
 ## Requirements for End Users using CMake
 
+*   We aim to support all platforms supported by the
+    [Google foundational C++ support policy](https://opensource.google/documentation/policies/cplusplus-support)
 *   [CMake](http://www.cmake.org/) >= 3.5
-*   A C++ compiler with C++14 support, such as [g++ >= 5](https://gcc.gnu.org/)
+*   A C++ compiler with C++17 support, such as
+    [g++ >= 7.5](https://gcc.gnu.org/) or
+    [clang >= 7.0.0](https://clang.llvm.org/)
 *   [Abseil](https://github.com/abseil/abseil-cpp) >= LTS
     [`20240722`](https://github.com/abseil/abseil-cpp/releases/tag/20240722.0)
     (standard library extensions)
@@ -83,8 +88,6 @@ cmake -DGOOGLETEST_ROOT=/opt/local/src -DCMAKE_PREFIX_PATH=/opt/local ..
 
 in the build instructions below.
 
-Thorough testing has only been done on Ubuntu 14.04.3 and macOS 10.13.
-
 ## Build and Install
 
 You may either download the source as a ZIP archive, or [clone the git

src/python/s2_common.i

@@ -119,7 +119,7 @@ public:
 
 %typemap(argout) S2Error * {
   if(!$1->ok())
-    SWIG_exception(SWIG_ValueError, $1->text().c_str());
+    SWIG_exception(SWIG_ValueError, std::string($1->message()).c_str());
 }
 
 // This overload shadows the one the takes vector<uint64_t>&, and it

src/s2/_fp_contract_off.h

@@ -34,15 +34,17 @@
 // but it is not implemented in GCC because the standard pragma allows control
 // at the level of compound statements rather than entire functions.
 //
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=20785
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=37845
+//
 // This file may be included with other files in any order, as long as it
 // appears before the first non-inline function definition.  It is
 // named with an underscore so that it is included first among the S2 headers.
 
-#if defined(__clang__)
-// Clang supports the standard C++ pragma for turning off this optimization.
+// Assume all compilers support or ignore the standard pragma.
 #pragma STDC FP_CONTRACT OFF
 
-#elif defined(__GNUC__)
+#if defined(__GNUC__) && !defined(__clang__)
 // GCC defines its own pragma that operates at the function level rather than
 // the statement level.
 #pragma GCC optimize("fp-contract=off")

src/s2/base/commandlineflags.h

@@ -22,7 +22,6 @@
 #include "absl/flags/flag.h"
 
 #include "s2/base/commandlineflags_declare.h"
-#include "s2/base/types.h"
 
 #define S2_DEFINE_bool(name, default_value, description) \
   ABSL_FLAG(bool, name, default_value, description)

src/s2/base/commandlineflags_declare.h

@@ -21,7 +21,6 @@
 
 #include "absl/flags/declare.h"
 
-#include "s2/base/types.h"
 
 #define S2_DECLARE_bool(name) ABSL_DECLARE_FLAG(bool, name)
 

src/s2/base/port.h

@@ -24,6 +24,7 @@
 
 #include <cstdint>
 #include <cstring>
+#include <new>
 
 // -----------------------------------------------------------------------------
 // Utility Functions
@@ -45,7 +46,7 @@ inline void sized_delete_array(void *ptr, size_t size) {
 // -----------------------------------------------------------------------------
 
 // IS_LITTLE_ENDIAN, IS_BIG_ENDIAN
-#if defined(__linux__) || defined(__ANDROID__)
+#if defined(__linux__)
 #include <endian.h>
 
 #elif defined(__APPLE__)

src/s2/base/spinlock.h

@@ -16,11 +16,11 @@
 #ifndef S2_BASE_SPINLOCK_H_
 #define S2_BASE_SPINLOCK_H_
 
-#include <absl/base/thread_annotations.h>
-
 #include <atomic>
 
-class ABSL_LOCKABLE SpinLock {
+#include <absl/base/thread_annotations.h>
+
+class ABSL_LOCKABLE ABSL_ATTRIBUTE_WARN_UNUSED SpinLock {
  public:
   SpinLock() = default;
   ~SpinLock() = default;
@@ -38,13 +38,15 @@ class ABSL_LOCKABLE SpinLock {
     locked_.store(false, std::memory_order_release);
   }
 
-  inline bool IsHeld() const { return locked_.load(std::memory_order_relaxed); }
+  ABSL_MUST_USE_RESULT inline bool IsHeld() const {
+    return locked_.load(std::memory_order_relaxed);
+  }
 
  private:
   std::atomic_bool locked_{false};
 };
 
-class ABSL_SCOPED_LOCKABLE SpinLockHolder {
+class ABSL_MUST_USE_RESULT ABSL_SCOPED_LOCKABLE SpinLockHolder {
  public:
   inline explicit SpinLockHolder(SpinLock* l) ABSL_EXCLUSIVE_LOCK_FUNCTION(l)
       : lock_(l) {

src/s2/base/types.h

@@ -24,6 +24,7 @@
 
 #include "absl/types/span.h"
 #include "s2/util/coding/coder.h"
+#include "s2/_fp_contract_off.h"  // IWYU pragma: keep
 #include "s2/encoded_uint_vector.h"
 #include "s2/s2cell_id.h"