boost: Improve option for i18n backend

recipes/boost/all/conandata.yml

@@ -56,6 +56,8 @@ patches:
       base_path: "source_subfolder"
     - patch_file: "patches/support_msvc_2019.patch"
       base_path: "source_subfolder"
+    - patch_file: "patches/boost_locale_fail_on_missing_backend.patch"
+      base_path: "source_subfolder"
   1.70.0:
     - patch_file: "patches/0001-beast-fix-moved-from-executor.patch"
       base_path: "source_subfolder"
@@ -69,6 +71,8 @@ patches:
       base_path: "source_subfolder"
     - patch_file: "patches/solaris_pthread_data.patch"
       base_path: "source_subfolder"
+    - patch_file: "patches/boost_locale_fail_on_missing_backend.patch"
+      base_path: "source_subfolder"
   1.71.0:
     - patch_file: "patches/bcp_namespace_issues_1_71.patch"
       base_path: "source_subfolder"
@@ -80,6 +84,8 @@ patches:
       base_path: "source_subfolder"
     - patch_file: "patches/solaris_pthread_data.patch"
       base_path: "source_subfolder"
+    - patch_file: "patches/boost_locale_fail_on_missing_backend.patch"
+      base_path: "source_subfolder"
   1.72.0:
     - patch_file: "patches/bcp_namespace_issues_1_72.patch"
       base_path: "source_subfolder"
@@ -95,18 +101,29 @@ patches:
       base_path: "source_subfolder"
     - patch_file: "patches/boost_log_filesystem_no_deprecated_1_72.patch"
       base_path: "source_subfolder"
+    - patch_file: "patches/boost_locale_fail_on_missing_backend.patch"
+      base_path: "source_subfolder"
   1.73.0:
     - patch_file: "patches/boost_build_qcc_fix_debug_build_parameter.patch"
       base_path: "source_subfolder"
     - patch_file: "patches/python_base_prefix.patch"
       base_path: "source_subfolder"
+    - patch_file: "patches/boost_locale_fail_on_missing_backend.patch"
+      base_path: "source_subfolder"
   1.74.0:
     - patch_file: "patches/boost_build_qcc_fix_debug_build_parameter_since_1_74.patch"
       base_path: "source_subfolder"
     - patch_file: "patches/python_base_prefix_since_1_74.patch"
       base_path: "source_subfolder"
+    - patch_file: "patches/boost_locale_fail_on_missing_backend.patch"
+      base_path: "source_subfolder"
   1.75.0:
     - patch_file: "patches/boost_build_qcc_fix_debug_build_parameter_since_1_74.patch"
       base_path: "source_subfolder"
     - patch_file: "patches/python_base_prefix_since_1_74.patch"
       base_path: "source_subfolder"
+    - patch_file: "patches/boost_locale_fail_on_missing_backend.patch"
+      base_path: "source_subfolder"
+  1.76.0:
+    - patch_file: "patches/boost_locale_fail_on_missing_backend.patch"
+      base_path: "source_subfolder"

recipes/boost/all/conanfile.py

@@ -92,7 +92,9 @@ class BoostConan(ConanFile):
         "debug_level": [i for i in range(0, 14)],
         "pch": [True, False],
         "extra_b2_flags": "ANY",  # custom b2 flags
-        "i18n_backend": ["iconv", "icu", None],
+        "i18n_backend": ["iconv", "icu", None, "deprecated"],
+        "i18n_backend_iconv": ["libc", "libiconv", "off"],
+        "i18n_backend_icu": [True, False],
         "visibility": ["global", "protected", "hidden"],
     }
     options.update({"without_{}".format(_name): [True, False] for _name in CONFIGURE_OPTIONS})
@@ -122,7 +124,9 @@ class BoostConan(ConanFile):
         "debug_level": 0,
         "pch": True,
         "extra_b2_flags": "None",
-        "i18n_backend": "iconv",
+        "i18n_backend": "deprecated",
+        "i18n_backend_iconv": "libc",
+        "i18n_backend_icu": False,
         "visibility": "hidden",
     }
     default_options.update({"without_{}".format(_name): False for _name in CONFIGURE_OPTIONS})
@@ -225,6 +229,10 @@ def _python_executable(self):
         exe = self.options.python_executable if self.options.python_executable else sys.executable
         return str(exe).replace('\\', '/')
 
+    @property
+    def _is_windows_platform(self):
+        return self.settings.os in ["Windows", "WindowsStore", "WindowsCE"]
+
     def config_options(self):
         if self.settings.os == "Windows":
             del self.options.fPIC
@@ -253,6 +261,11 @@ def config_options(self):
                 self.options.without_json = True
                 self.options.without_nowide = True
 
+        # iconv is off by default on Windows and Solaris
+        if self._is_windows_platform or self.settings.os == "SunOS":
+            self.options.i18n_backend_iconv = "off"
+        elif self.settings.os == "Macos":
+            self.options.i18n_backend_iconv = "libiconv"
 
         # Remove options not supported by this version of boost
         for dep_name in CONFIGURE_OPTIONS:
@@ -304,11 +317,23 @@ def configure(self):
         elif self.options.shared:
             del self.options.fPIC
 
+        if self.options.i18n_backend != "deprecated":
+            self.output.warn("i18n_backend option is deprecated, do not use anymore.")
+            if self.options.i18n_backend == "iconv":
+                self.options.i18n_backend_iconv = "libiconv"
+                self.options.i18n_backend_icu = False
+            if self.options.i18n_backend == "icu":
+                self.options.i18n_backend_iconv = "off"
+                self.options.i18n_backend_icu = True
+            if self.options.i18n_backend == "None":
+                self.options.i18n_backend_iconv = "off"
+                self.options.i18n_backend_icu = False
         if self.options.without_locale:
-            self.options.i18n_backend = None
+            del self.options.i18n_backend_iconv
+            del self.options.i18n_backend_icu
         else:
-            if not self.options.i18n_backend:
-                raise ConanInvalidConfiguration("Boost.locale library requires a i18n_backend (either 'icu' or 'iconv')")
+            if self.options.i18n_backend_iconv == "off" and not self.options.i18n_backend_icu and not self._is_windows_platform:
+                raise ConanInvalidConfiguration("Boost.Locale library needs either iconv or ICU library to be built on non windows platforms")
 
         if not self.options.without_python:
             if not self.options.python_version:
@@ -418,11 +443,11 @@ def _with_zstd(self):
 
     @property
     def _with_icu(self):
-        return not self.options.header_only and self._with_dependency("icu") and self.options.i18n_backend == "icu"
+        return not self.options.header_only and self._with_dependency("icu") and self.options.get_safe("i18n_backend_icu")
 
     @property
     def _with_iconv(self):
-        return not self.options.header_only and self._with_dependency("iconv") and self.options.i18n_backend == "iconv"
+        return not self.options.header_only and self._with_dependency("iconv") and self.options.get_safe("i18n_backend_iconv") == "libiconv"
 
     def requirements(self):
         if self._with_zlib:
@@ -436,10 +461,12 @@ def requirements(self):
 
         if self._with_icu:
             self.requires("icu/68.2")
-        elif self._with_iconv:
+        if self._with_iconv:
             self.requires("libiconv/1.16")
 
     def package_id(self):
+        del self.info.options.i18n_backend
+
         if self.options.header_only:
             self.info.header_only()
             self.info.options.header_only = True
@@ -837,15 +864,20 @@ def _build_flags(self):
         flags.append("-sNO_LZMA=%s" % ("0" if self._with_lzma else "1"))
         flags.append("-sNO_ZSTD=%s" % ("0" if self._with_zstd else "1"))
 
-        if self.options.i18n_backend == 'icu':
-            flags.append("-sICU_PATH={}".format(self.deps_cpp_info["icu"].rootpath))
-            flags.append("boost.locale.iconv=off boost.locale.icu=on")
-        elif self.options.i18n_backend == 'iconv':
-            flags.append("boost.locale.iconv=on boost.locale.icu=off")
+        if self.options.get_safe("i18n_backend_icu"):
+            flags.append("boost.locale.icu=on")
+        else:
+            flags.append("boost.locale.icu=off")
             flags.append("--disable-icu")
+        if self.options.get_safe("i18n_backend_iconv") in ["libc", "libiconv"]:
+            flags.append("boost.locale.iconv=on")
+            if self.options.get_safe("i18n_backend_iconv") == "libc":
+                flags.append("boost.locale.iconv.lib=libc")
+            else:
+                flags.append("boost.locale.iconv.lib=libiconv")
         else:
-            flags.append("boost.locale.iconv=off boost.locale.icu=off")
-            flags.append("--disable-icu --disable-iconv")
+            flags.append("boost.locale.iconv=off")
+            flags.append("--disable-iconv")
 
         def add_defines(library):
             for define in self.deps_cpp_info[library].defines:
@@ -1389,7 +1421,9 @@ def filter_transform_module_libraries(names):
                     if conan_requirement not in self.requires:
                         continue
                     if module == "locale" and requirement in ("icu", "iconv"):
-                        if requirement != self.options.i18n_backend:
+                        if requirement == "icu" and not self._with_icu:
+                            continue
+                        if requirement == "iconv" and not self._with_iconv:
                             continue
                     self.cpp_info.components[module].requires.append("{0}::{0}".format(conan_requirement))
             for incomplete_component in incomplete_components:

recipes/boost/all/patches/boost_locale_fail_on_missing_backend.patch

@@ -0,0 +1,53 @@
+diff --git a/libs/locale/build/Jamfile.v2 b/libs/locale/build/Jamfile.v2
+index 578e722..b715f59 100644
+--- a/libs/locale/build/Jamfile.v2
++++ b/libs/locale/build/Jamfile.v2
+@@ -17,6 +17,7 @@ import feature ;
+ # Features
+
+ feature.feature boost.locale.iconv : on off : optional propagated ;
++feature.feature boost.locale.iconv.lib : libc libiconv : optional propagated ;
+ feature.feature boost.locale.icu : on off :  optional propagated ;
+ feature.feature boost.locale.posix : on off : optional propagated ;
+ feature.feature boost.locale.std : on off : optional propagated ;
+@@ -217,6 +218,14 @@ rule configure-full ( properties * : flags-only )
+         if [ configure.builds has_iconv : $(properties) : "iconv (libc)" ]
+         {
+             found-iconv = true ;
++            if <boost.locale.iconv.lib>libiconv in $(properties)
++            {
++                EXIT "- Boost.Locale found iconv (libc) instead of iconv (separate) library to be built." ;
++            }
++        }
++        else if <boost.locale.iconv.lib>libc in $(properties)
++        {
++            EXIT "- Boost.Locale failed to find iconv (libc) library to be built." ;
+         }
+         else 
+         {
+@@ -225,6 +234,14 @@ rule configure-full ( properties * : flags-only )
+                 found-iconv = true ;
+                 result += <library>iconv ;
+             }
++            else if <boost.locale.iconv.lib>libiconv in $(properties)
++            {
++                EXIT "- Boost.Locale failed to find iconv (separate) library to be built." ;
++            }
++        }
++        if ! $(found-iconv)
++        {
++            EXIT "- Boost.Locale failed to find iconv library to be built." ;
+         }
+     }        
+     if $(found-iconv) 
+@@ -265,6 +282,10 @@ rule configure-full ( properties * : flags-only )
+                       <library>../../thread/build//boost_thread 
+                       ;
+         }
++        else
++        {
++            EXIT "- Boost.Locale failed to find ICU library to be built." ;
++        }
+
+     }
+