rust: Add new `rust_dependency_map` target configuration

This allows changing the crate name with which a library ends up being
available inside the Rust code, similar to cargo's dependency renaming
feature or `extern crate foo as bar` inside Rust code.

docs/markdown/snippets/rust_dependency_map.md

@@ -0,0 +1,18 @@
+## Support for defining crate names of Rust dependencies in Rust targets
+
+Rust supports defining a different crate name for a dependency than what the
+actual crate name during compilation of that dependency was.
+
+This allows using multiple versions of the same crate at once, or simply using
+a shorter name of the crate for convenience.
+
+```meson
+a_dep = dependency('some-very-long-name')
+
+my_executable = executable('my-executable', 'src/main.rs',
+  rust_dependency_map : {
+    'some_very_long_name' : 'a',
+  },
+  dependencies : [a_dep],
+)
+```

docs/yaml/functions/_build_target_base.yaml

@@ -302,3 +302,13 @@ kwargs:
       "proc-macro" is a special rust procedural macro crate.
 
       "proc-macro" is new in 0.62.0.
+
+  rust_dependency_map:
+    type: dict[str]
+    since: 1.2.0
+    description: |
+      On rust targets this provides a map of library names to the crate name
+      with which it would be available inside the rust code.
+
+      This allows renaming similar to the dependency renaming feature of cargo
+      or `extern crate foo as bar` inside rust code.

mesonbuild/backend/ninjabackend.py

@@ -50,7 +50,7 @@ if T.TYPE_CHECKING:
     from typing_extensions import Literal
 
     from .._typing import ImmutableListProtocol
-    from ..build import ExtractedObjects
+    from ..build import ExtractedObjects, LibTypes
     from ..interpreter import Interpreter
     from ..linkers import DynamicLinker, StaticLinker
     from ..compilers.cs import CsCompiler
@@ -1830,6 +1830,12 @@ class NinjaBackend(backends.Backend):
 
         self.rust_crates[name] = crate
 
+    def _get_rust_dependency_name(self, target: build.BuildTarget, dependency: LibTypes) -> str:
+        # Convert crate names with dashes to underscores by default like
+        # cargo does as dashes can't be used as parts of identifiers
+        # in Rust
+        return target.rust_dependency_map.get(dependency.name, dependency.name).replace('-', '_')
+
     def generate_rust_target(self, target: build.BuildTarget) -> None:
         rustc = target.compilers['rust']
         # Rust compiler takes only the main file as input and
@@ -1936,11 +1942,7 @@ class NinjaBackend(backends.Backend):
                 # specify `extern CRATE_NAME=OUTPUT_FILE` for each Rust
                 # dependency, so that collisions with libraries in rustc's
                 # sysroot don't cause ambiguity
-                #
+                d_name = self._get_rust_dependency_name(target, d)
-                # Also convert crate names with dashes to underscores like
-                # cargo does as dashes can't be used as parts of identifiers
-                # in Rust
-                d_name = d.name.replace('-', '_')
                 args += ['--extern', '{}={}'.format(d_name, os.path.join(d.subdir, d.filename))]
                 project_deps.append(RustDep(d_name, self.rust_crates[d.name].order))
             elif isinstance(d, build.StaticLibrary):
@@ -1979,11 +1981,7 @@ class NinjaBackend(backends.Backend):
                 # specify `extern CRATE_NAME=OUTPUT_FILE` for each Rust
                 # dependency, so that collisions with libraries in rustc's
                 # sysroot don't cause ambiguity
-                #
+                d_name = self._get_rust_dependency_name(target, d)
-                # Also convert crate names with dashes to underscores like
-                # cargo does as dashes can't be used as parts of identifiers
-                # in Rust
-                d_name = d.name.replace('-', '_')
                 args += ['--extern', '{}={}'.format(d_name, os.path.join(d.subdir, d.filename))]
                 project_deps.append(RustDep(d_name, self.rust_crates[d.name].order))
             else:

mesonbuild/build.py

@@ -74,7 +74,7 @@ lang_arg_kwargs |= {
 }
 
 vala_kwargs = {'vala_header', 'vala_gir', 'vala_vapi'}
-rust_kwargs = {'rust_crate_type'}
+rust_kwargs = {'rust_crate_type', 'rust_dependency_map'}
 cs_kwargs = {'resources', 'cs_args'}
 
 buildtarget_kwargs = {
@@ -1239,6 +1239,13 @@ class BuildTarget(Target):
             if self.gnu_symbol_visibility not in permitted:
                 raise InvalidArguments('GNU symbol visibility arg {} not one of: {}'.format(self.gnu_symbol_visibility, ', '.join(permitted)))
 
+        rust_dependency_map = kwargs.get('rust_dependency_map', {})
+        if not isinstance(rust_dependency_map, dict):
+            raise InvalidArguments(f'Invalid rust_dependency_map "{rust_dependency_map}": must be a dictionary.')
+        if any(not isinstance(v, str) for v in rust_dependency_map.values()):
+            raise InvalidArguments(f'Invalid rust_dependency_map "{rust_dependency_map}": must be a dictionary with string values.')
+        self.rust_dependency_map = rust_dependency_map
+
     def validate_win_subsystem(self, value: str) -> str:
         value = value.lower()
         if re.fullmatch(r'(boot_application|console|efi_application|efi_boot_service_driver|efi_rom|efi_runtime_driver|native|posix|windows)(,\d+(\.\d+)?)?', value) is None:

mesonbuild/interpreter/interpreter.py

@@ -3183,6 +3183,7 @@ class Interpreter(InterpreterBase, HoldableObject):
             raise InterpreterException(f'Unknown default_library value: {default_library}.')
 
     def build_target(self, node: mparser.BaseNode, args, kwargs, targetclass):
+        @FeatureNewKwargs('build target', '1.2.0', ['rust_dependency_map'])
         @FeatureNewKwargs('build target', '0.42.0', ['rust_crate_type', 'build_rpath', 'implicit_include_directories'])
         @FeatureNewKwargs('build target', '0.41.0', ['rust_args'])
         @FeatureNewKwargs('build target', '0.38.0', ['build_by_default'])

test cases/rust/17 staticlib link staticlib/branch.rs

@@ -1,4 +1,4 @@
 #[no_mangle]
 pub extern "C" fn what_have_we_here() -> i32 {
-    leaf::HOW_MANY * leaf::HOW_MANY
+    myleaf::HOW_MANY * myleaf::HOW_MANY
 }

test cases/rust/17 staticlib link staticlib/meson.build

@@ -3,6 +3,6 @@ project('staticlib link staticlib', 'c', 'rust')
 leaf = static_library('leaf', 'leaf.rs', rust_crate_type : 'rlib')
 # Even though leaf is linked using link_with, this gets implicitly promoted to link_whole because
 # it is an internal Rust project.
-branch = static_library('branch', 'branch.rs', link_with: leaf, rust_crate_type : 'staticlib', install : true)
+branch = static_library('branch', 'branch.rs', link_with: leaf, rust_crate_type : 'staticlib', rust_dependency_map : { 'leaf' : 'myleaf' }, install : true)
 e = executable('prog', 'prog.c', link_with : branch, install : true)
 test('linktest', e)