Removed BOOST_BEAST_USE_STD_STRING_VIEW (#2451)

Fixes #2363

.drone.star

@@ -56,9 +56,9 @@ def main(ctx):
   linux_cxx("clang 6.0 libc++", "clang++-6.0", packages="clang-6.0 libc6-dbg libc++-dev libstdc++-8-dev libc++abi-dev", llvm_os="bionic", llvm_ver="6.0", buildtype="boost", buildscript="drone", image=linuxglobalimage, environment={'B2_TOOLSET': 'clang', 'COMPILER': 'clang++-6.0', 'B2_CXXSTD': '11,14', 'B2_STDLIB': 'libc++', 'DRONE_JOB_UUID': 'b3f0c7f6bb'}, globalenv=globalenv),
   osx_cxx("clang", "g++", packages="", buildtype="boost", buildscript="drone", environment={'B2_TOOLSET': 'clang', 'B2_CXXSTD': '11,17', 'DRONE_JOB_UUID': '91032ad7bb'}, globalenv=globalenv),
   linux_cxx("coverity", "g++", packages="", buildtype="coverity", buildscript="drone", image=linuxglobalimage, environment={'COMMENT': 'Coverity Scan', 'B2_TOOLSET': 'clang', 'DRONE_JOB_UUID': '472b07b9fc'}, globalenv=globalenv),
-  windows_cxx("msvc-14.1", "", image="cppalliance/dronevs2017", buildtype="boost", buildscript="drone", environment={ "VARIANT": "release", "TOOLSET": "msvc-14.1", "CXXSTD": "17", "DEFINE" : "BOOST_BEAST_USE_STD_STRING_VIEW", "ADDRESS_MODEL": "64"}),
-  windows_cxx("msvc-14.2", "", image="cppalliance/dronevs2019", buildtype="boost", buildscript="drone", environment={ "VARIANT": "release", "TOOLSET": "msvc-14.2", "CXXSTD": "17", "DEFINE" : "BOOST_BEAST_USE_STD_STRING_VIEW", "ADDRESS_MODEL": "64"}),
-  windows_cxx("msvc-14.3", "", image="cppalliance/dronevs2022:1", buildtype="boost", buildscript="drone", environment={ "VARIANT": "release", "TOOLSET": "msvc-14.3", "CXXSTD": "20", "DEFINE" : "BOOST_BEAST_USE_STD_STRING_VIEW", "ADDRESS_MODEL": "64"}),
+  windows_cxx("msvc-14.1", "", image="cppalliance/dronevs2017", buildtype="boost", buildscript="drone", environment={ "VARIANT": "release", "TOOLSET": "msvc-14.1", "CXXSTD": "17", "ADDRESS_MODEL": "64"}),
+  windows_cxx("msvc-14.2", "", image="cppalliance/dronevs2019", buildtype="boost", buildscript="drone", environment={ "VARIANT": "release", "TOOLSET": "msvc-14.2", "CXXSTD": "17", "ADDRESS_MODEL": "64"}),
+  windows_cxx("msvc-14.3", "", image="cppalliance/dronevs2022:1", buildtype="boost", buildscript="drone", environment={ "VARIANT": "release", "TOOLSET": "msvc-14.3", "CXXSTD": "20", "ADDRESS_MODEL": "64"}),
     ]
 
 # from https://github.com/boostorg/boost-ci

.drone/drone.bat

@@ -22,16 +22,18 @@ b2 headers
 
 echo "============> SCRIPT"
 
+IF DEFINED DEFINE SET B2_DEFINE="define=%DEFINE%"
+
 echo "Running tests"
-b2 --debug-configuration variant=%VARIANT% cxxstd=%CXXSTD% define=%DEFINE% address-model=%ADDRESS_MODEL% toolset=%TOOLSET% --verbose-test libs/beast/test -j3
+b2 --debug-configuration variant=%VARIANT% cxxstd=%CXXSTD% %B2_DEFINE% address-model=%ADDRESS_MODEL% toolset=%TOOLSET% --verbose-test libs/beast/test -j3
 if !errorlevel! neq 0 exit /b !errorlevel!
 
 echo "Running libs/beast/example"
-b2 --debug-configuration variant=%VARIANT% cxxstd=%CXXSTD% define=%DEFINE% address-model=%ADDRESS_MODEL% toolset=%TOOLSET% libs/beast/example -j3
+b2 --debug-configuration variant=%VARIANT% cxxstd=%CXXSTD% %B2_DEFINE% address-model=%ADDRESS_MODEL% toolset=%TOOLSET% libs/beast/example -j3
 if !errorlevel! neq 0 exit /b !errorlevel!
 
 echo "Running run-fat-tests"
-b2 --debug-configuration variant=%VARIANT% cxxstd=%CXXSTD% define=%DEFINE% address-model=%ADDRESS_MODEL% toolset=%TOOLSET% --verbose-test libs/beast/test//run-fat-tests -j3
+b2 --debug-configuration variant=%VARIANT% cxxstd=%CXXSTD% %B2_DEFINE% address-model=%ADDRESS_MODEL% toolset=%TOOLSET% --verbose-test libs/beast/test//run-fat-tests -j3
 if !errorlevel! neq 0 exit /b !errorlevel!
 
 echo "============> COMPLETED"

CHANGELOG.md

@@ -1,3 +1,11 @@
+Version 339:
+
+* BOOST_BEAST_USE_STD_STRING_VIEW is replaced by boost/core string_view.
+* defining BOOST_BEAST_USE_STD_STRING_VIEW yields a deprecation warning
+
+--------------------------------------------------------------------------------
+
+
 Version 338:
 
 * Added per message compression options.

appveyor.yml

@@ -47,8 +47,8 @@ build: off
 test_script:
   - b2 --debug-configuration variant=release cxxstd=14 address-model=64 toolset=msvc-14.0 libs/beast/example -j3
   - b2 --debug-configuration variant=release cxxstd=14 address-model=64 toolset=msvc-14.0 --verbose-test libs/beast/test//run-fat-tests -j3
-  - b2 --debug-configuration variant=release cxxstd=17 define="BOOST_BEAST_USE_STD_STRING_VIEW" address-model=64 toolset=msvc-14.1 libs/beast/example -j3
-  - b2 --debug-configuration variant=release cxxstd=17 define="BOOST_BEAST_USE_STD_STRING_VIEW" address-model=64 toolset=msvc-14.1 --verbose-test libs/beast/test//run-fat-tests -j3
+  - b2 --debug-configuration variant=release cxxstd=17 address-model=64 toolset=msvc-14.1 libs/beast/example -j3
+  - b2 --debug-configuration variant=release cxxstd=17 address-model=64 toolset=msvc-14.1 --verbose-test libs/beast/test//run-fat-tests -j3
 
 cache:
 - c:\tools\vcpkg\installed\

azure-pipelines.yml

@@ -42,7 +42,6 @@ jobs:
           CXX: g++-9
           PACKAGES: g++-9
           VARIANT: release
-          B2_FLAGS: <define>BOOST_BEAST_USE_STD_STRING_VIEW
           CXXSTD: 17
           B2_TARGETS: libs/beast/test//run-fat-tests libs/beast/example
         GCC 9 C++11 HEADER_ONLY NO_DEPRECATED:
@@ -86,7 +85,6 @@ jobs:
           CXX: g++-8
           PACKAGES: g++-8
           VARIANT: release
-          B2_FLAGS: <define>BOOST_BEAST_USE_STD_STRING_VIEW
           CXXSTD: 17
           B2_TARGETS: libs/beast/test//run-fat-tests libs/beast/example
         GCC 8 C++11 HEADER_ONLY NO_DEPRECATED:
@@ -303,13 +301,11 @@ jobs:
         MSVC14.2 C++17 x64:
           VM_IMAGE: 'windows-2019'
           TOOLSET: msvc-14.2
-          B2_FLAGS: define=BOOST_BEAST_USE_STD_STRING_VIEW
           CXXSTD: 17
           ADDRMODEL: 64
         MSVC14.1 C++17 x64:
           VM_IMAGE: 'vs2017-win2016'
           TOOLSET: msvc-14.1
-          B2_FLAGS: define=BOOST_BEAST_USE_STD_STRING_VIEW
           CXXSTD: 17
           ADDRMODEL: 64
         MSVC14.0 C++11 x64:

doc/qbk/03_core/8_conf_macros.qbk

@@ -18,14 +18,6 @@ failure to do so may result in violations of ODR (One Definition Rule).
 
 [table Special Fields
 [[Definition][Description]]
-[
-    [
-        BOOST_BEAST_USE_STD_STRING_VIEW
-    ][
-        Causes Beast to use std::string_view instead of boost::string_view.
-        Requires C++17.
-    ]
-]
 [
     [
         BOOST_BEAST_SEPARATE_COMPILATION

doc/qbk/release_notes.qbk

@@ -15,6 +15,7 @@
 
 [*Miscellaneous]
 
+* [issue 2363] Remove `BOOST_BEAST_USE_STD_STRING_VIEW`
 * [issue 2417] use boost::core::string_view. This improves inter-conversion between string_view implementations. Some observable differences for users:
  * `core::string_view` no longer supports the `.to_string()` or `.clear()` extensions from Utility
  * code that relied on `.max_size()` returning `.size(),` needs to be fixed to use `.size()` instead

include/boost/beast/core/string_type.hpp

@@ -12,32 +12,22 @@
 
 #include <boost/beast/core/detail/config.hpp>
 
-#if defined(BOOST_BEAST_USE_STD_STRING_VIEW)
-#include <string_view>
-#else
 #include <boost/core/detail/string_view.hpp>
+#if defined(BOOST_BEAST_USE_STD_STRING_VIEW)
+#include <boost/config/pragma_message.hpp>
+BOOST_PRAGMA_MESSAGE("BOOST_BEAST_USE_STD_STRING_VIEW is deprecated, use BOOST_NO_CXX17_HDR_STRING_VIEW instead");
 #endif
 
 namespace boost {
 namespace beast {
 
-#if BOOST_BEAST_DOXYGEN || ! defined(BOOST_BEAST_USE_STD_STRING_VIEW)
 /// The type of string view used by the library
 using string_view = boost::core::string_view;
 
 /// The type of `basic_string_view` used by the library
-template<class CharT, class Traits>
+template<class CharT>
 using basic_string_view =
-    boost::basic_string_view<CharT, Traits>;
-
-#else
-using string_view = std::string_view;
-
-template<class CharT, class Traits>
-using basic_string_view =
-    std::basic_string_view<CharT, Traits>;
-
-#endif
+    boost::core::basic_string_view<CharT>;
 
 template<class S>
 inline string_view