add default_both_libraries core option

docs/markdown/Builtin-options.md

@@ -79,6 +79,7 @@ machine](#specifying-options-per-machine) section for details.
 | genvslite {vs2022}                     | vs2022        | Setup multi-builtype ninja build directories and Visual Studio solution | no | no |
 | buildtype {plain, debug,<br>debugoptimized, release, minsize, custom} | debug | Build type to use                       | no             | no                |
 | debug                                  | true          | Enable debug symbols and other information                     | no             | no                |
+| default_both_libraries {shared, static, auto} | shared | Default library type for both_libraries                        | no             | no                |
 | default_library {shared, static, both} | shared        | Default library type                                           | no             | yes               |
 | errorlogs                              | true          | Whether to print the logs from failing tests.                  | no             | no                |
 | install_umask {preserve, 0000-0777}    | 022           | Default umask to apply on permissions of installed files       | no             | no                |
@@ -177,6 +178,16 @@ fails.
 
 `vsenv` is `true` by default when using the `vs` backend.
 
+
+#### Details for `default_both_libraries`
+
+Since `1.6.0`, you can select the default type of library selected when using
+a `both_libraries` object. This can be either 'shared' (default value, compatible
+with previous meson versions), 'static', or 'auto'. With auto, the value from
+`default_library` option is used, unless it is 'both', in which case 'shared'
+is used instead.
+
+
 ## Base options
 
 These are set in the same way as universal options, either by

docs/markdown/snippets/default_both_libraries.md

@@ -0,0 +1,4 @@
+## New built-in option for default both_libraries
+
+`both_libraries` targets used to be considered as a shared library by default.
+There is now the `default_both_libraries` option to change this default.

mesonbuild/build.py

@@ -2486,8 +2486,8 @@ class SharedModule(SharedLibrary):
         return self.environment.get_shared_module_dir(), '{moduledir_shared}'
 
 class BothLibraries(SecondLevelHolder):
-    def __init__(self, shared: SharedLibrary, static: StaticLibrary) -> None:
+    def __init__(self, shared: SharedLibrary, static: StaticLibrary, preferred_library: Literal['shared', 'static', 'auto']) -> None:
-        self._preferred_library = 'shared'
+        self._preferred_library = preferred_library
         self.shared = shared
         self.static = static
         self.subproject = self.shared.subproject

mesonbuild/interpreter/interpreter.py

@@ -3230,6 +3230,11 @@ class Interpreter(InterpreterBase, HoldableObject):
     def build_both_libraries(self, node: mparser.BaseNode, args: T.Tuple[str, SourcesVarargsType], kwargs: kwtypes.Library) -> build.BothLibraries:
         shared_lib = self.build_target(node, args, kwargs, build.SharedLibrary)
         static_lib = self.build_target(node, args, kwargs, build.StaticLibrary)
+        preferred_library = self.coredata.get_option(OptionKey('default_both_libraries'))
+        if preferred_library == 'auto':
+            preferred_library = self.coredata.get_option(OptionKey('default_library'))
+            if preferred_library == 'both':
+                preferred_library = 'shared'
 
         if self.backend.name == 'xcode':
             # Xcode is a bit special in that you can't (at least for the moment)
@@ -3261,7 +3266,7 @@ class Interpreter(InterpreterBase, HoldableObject):
             # Keep only compilers used for linking
             static_lib.compilers = {k: v for k, v in static_lib.compilers.items() if k in compilers.clink_langs}
 
-        return build.BothLibraries(shared_lib, static_lib)
+        return build.BothLibraries(shared_lib, static_lib, preferred_library)
 
     def build_library(self, node: mparser.BaseNode, args: T.Tuple[str, SourcesVarargsType], kwargs: kwtypes.Library):
         default_library = self.coredata.get_option(OptionKey('default_library', subproject=self.subproject))

mesonbuild/options.py

@@ -63,6 +63,7 @@ _BUILTIN_NAMES = {
     'buildtype',
     'debug',
     'default_library',
+    'default_both_libraries',
     'errorlogs',
     'genvslite',
     'install_umask',
@@ -624,6 +625,7 @@ BUILTIN_CORE_OPTIONS: T.Dict['OptionKey', 'BuiltinOption'] = OrderedDict([
     (OptionKey('debug'),           BuiltinOption(UserBooleanOption, 'Enable debug symbols and other information', True)),
     (OptionKey('default_library'), BuiltinOption(UserComboOption, 'Default library type', 'shared', choices=['shared', 'static', 'both'],
                                                  yielding=False)),
+    (OptionKey('default_both_libraries'), BuiltinOption(UserComboOption, 'Default library type for both_libraries', 'shared', choices=['shared', 'static', 'auto'])),
     (OptionKey('errorlogs'),       BuiltinOption(UserBooleanOption, "Whether to print the logs from failing tests", True)),
     (OptionKey('install_umask'),   BuiltinOption(UserUmaskOption, 'Default umask to apply on permissions of installed files', '022')),
     (OptionKey('layout'),          BuiltinOption(UserComboOption, 'Build directory layout', 'mirror', choices=['mirror', 'flat'])),

test cases/common/273 both libraries/meson.build

@@ -0,0 +1,44 @@
+project(
+    'test both libraries',
+    'c',
+    meson_version: '>= 1.6.0',
+)
+
+expected = 0
+
+
+with_library = library(
+    'with_library',
+    files('src/library.c'),
+    c_shared_args: ['-DEXPORT'],
+)
+
+with_library_dep = declare_dependency(
+    link_with: with_library,
+)
+
+if get_option('default_library') == 'shared'
+    expected += 1
+elif get_option('default_library') == 'both'
+    if get_option('default_both_libraries') in ['shared', 'auto']
+        expected += 1
+    endif
+endif
+
+
+
+mainlink = executable(
+    'mainlink',
+    files('src/main.c'),
+    c_args: [f'-DEXPECTED=@expected@'],
+    link_with: [with_library],
+)
+test('link with', mainlink)
+
+maindep = executable(
+    'maindep',
+    files('src/main.c'),
+    c_args: [f'-DEXPECTED=@expected@'],
+    dependencies: [with_library_dep],
+)
+test('use dep', maindep)

test cases/common/273 both libraries/src/api.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#if defined EXPORT
+    #if defined _WIN32 || defined __CYGWIN__
+        #define API __declspec(dllexport)
+    #else
+        #if defined __GNUC__
+            #define API __attribute__((visibility("default")))
+        #else
+            #define API
+        #endif
+    #endif
+#else
+    #define API
+#endif

test cases/common/273 both libraries/src/library.c

@@ -0,0 +1,10 @@
+#include "library.h"
+
+int library_function(void)
+{
+#if defined EXPORT
+    return 1;
+#else
+    return 0;
+#endif
+}

test cases/common/273 both libraries/src/library.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include "api.h"
+
+int API library_function(void);

test cases/common/273 both libraries/src/main.c

@@ -0,0 +1,8 @@
+#include "library.h"
+
+
+int main(void)
+{
+    int sum = library_function();
+    return sum == EXPECTED ? 0 : sum;
+}

test cases/common/273 both libraries/test.json

@@ -0,0 +1,16 @@
+{
+    "matrix": {
+        "options": {
+            "default_library": [
+                { "val": "shared" },
+                { "val": "static" },
+                { "val": "both"   }
+            ],
+            "default_both_libraries": [
+                { "val": "shared" },
+                { "val": "static" },
+                { "val": "auto"   }
+            ]
+        }
+    }
+}