modules/rust: Add a keyword argument to pass extra args to the rust compiler

This may be necessary to, for example, stop rustc complaining about
unused functions

docs/markdown/Rust-module.md

@@ -18,7 +18,7 @@ like Meson, rather than Meson work more like rust.
 
 ## Functions
 
-### test(name: string, target: library | executable, dependencies: []Dependency, link_with: []targets)
+### test(name: string, target: library | executable, dependencies: []Dependency, link_with: []targets, rust_args: []string)
 
 This function creates a new rust unittest target from an existing rust
 based target, which may be a library or executable. It does this by
@@ -35,6 +35,8 @@ argument.
 
 *(since 1.2.0)* the link_with argument can be used to pass additional build
 targets to link with
+*(since 1.2.0)* the `rust_args` keyword argument can be ussed to pass extra
+arguments to the Rust compiler.
 
 ### bindgen(*, input: string | BuildTarget | [](string | BuildTarget), output: string, include_directories: [](include_directories | string), c_args: []string, args: []string, dependencies: []Dependency)
 

docs/markdown/snippets/rust_bindegen_extra_args.md

@@ -0,0 +1,3 @@
+## rust.bindgen allows passing extra arguments to rustc
+
+This may be necessary to pass extra `cfg`s or to change warning levels.

mesonbuild/modules/rust.py

@@ -40,6 +40,7 @@ if T.TYPE_CHECKING:
         dependencies: T.List[T.Union[Dependency, ExternalLibrary]]
         is_parallel: bool
         link_with: T.List[LibTypes]
+        rust_args: T.List[str]
 
     class FuncBindgen(TypedDict):
 
@@ -71,6 +72,13 @@ class RustModule(ExtensionModule):
         *TEST_KWS,
         DEPENDENCIES_KW,
         LINK_WITH_KW.evolve(since='1.2.0'),
+        KwargInfo(
+            'rust_args',
+            ContainerTypeInfo(list, str),
+            listify=True,
+            default=[],
+            since='1.2.0',
+        ),
         KwargInfo('is_parallel', bool, default=False),
     )
     def test(self, state: ModuleState, args: T.Tuple[str, BuildTarget], kwargs: FuncTest) -> ModuleReturnValue:
@@ -148,7 +156,8 @@ class RustModule(ExtensionModule):
         new_target_kwargs = base_target.kwargs.copy()
         # Don't mutate the shallow copied list, instead replace it with a new
         # one
-        new_target_kwargs['rust_args'] = new_target_kwargs.get('rust_args', []) + ['--test']
+        new_target_kwargs['rust_args'] = \
+            new_target_kwargs.get('rust_args', []) + kwargs['rust_args'] + ['--test']
         new_target_kwargs['install'] = False
         new_target_kwargs['dependencies'] = new_target_kwargs.get('dependencies', []) + kwargs['dependencies']
         new_target_kwargs['link_with'] = new_target_kwargs.get('link_with', []) + kwargs['link_with']

test cases/rust/9 unit tests/meson.build

@@ -31,17 +31,17 @@ test(
   suite : ['foo'],
 )
 
-exe = executable('rust_exe', ['test2.rs', 'test.rs'])
+exe = executable('rust_exe', ['test2.rs', 'test.rs'], build_by_default : false)
 
 rust = import('unstable-rust')
 rust.test('rust_test_from_exe', exe, should_fail : true)
 
-lib = static_library('rust_static', ['test.rs'])
+lib = static_library('rust_static', ['test.rs'], build_by_default : false)
 rust.test('rust_test_from_static', lib, args: ['--skip', 'test_add_intentional_fail'])
 
-lib = shared_library('rust_shared', ['test.rs'])
+lib = shared_library('rust_shared', ['test.rs'], build_by_default : false)
 rust.test('rust_test_from_shared', lib, args: ['--skip', 'test_add_intentional_fail'])
 
 helper = static_library('helper', 'helper.rs')
-lib = static_library('rust_link_with', 'test3.rs')
-rust.test('rust_test_link_with', lib, link_with : helper)
+lib = static_library('rust_link_with', 'test3.rs', build_by_default : false)
+rust.test('rust_test_link_with', lib, link_with : helper, rust_args : ['--cfg', 'broken="false"'])

test cases/rust/9 unit tests/test3.rs

@@ -8,6 +8,13 @@ mod tests {
 
         use super::*;
 
+        // This is an intentinally broken test that should be turned off by extra rust arguments
+        #[cfg(not(broken = "false"))]
+        #[test]
+        fn test_broken() {
+                assert_eq!(0, 5);
+        }
+
         #[test]
         fn test_add_sub() {
                 let x = helper::subtract(6, 5);