build: use an object rather than a dict for the dep_manifest

This really is more of a struct than a dict, as the types are disjoint
and they are internally handled, (ie, not from user input). This cleans
some things up, in addition I spotted a bug in the ModuleState where the
dict with the version and license is passed to a field that expects just
the version string.

7 files changed, 32 insertions, 15 deletions

diff --git a/mesonbuild/backend/backends.py b/mesonbuild/backend/backends.py
index 4570b00..bc2b74a 100644
--- a/mesonbuild/backend/backends.py
+++ b/mesonbuild/backend/backends.py
@@ -1144,7 +1144,8 @@ class Backend:
         ifilename = os.path.join(self.environment.get_build_dir(), 'depmf.json')
         ofilename = os.path.join(self.environment.get_prefix(), self.build.dep_manifest_name)
         out_name = os.path.join('{prefix}', self.build.dep_manifest_name)
-        mfobj = {'type': 'dependency manifest', 'version': '1.0', 'projects': self.build.dep_manifest}
+        mfobj = {'type': 'dependency manifest', 'version': '1.0',
+                 'projects': {k: v.to_json() for k, v in self.build.dep_manifest.items()}}
         with open(ifilename, 'w', encoding='utf-8') as f:
             f.write(json.dumps(mfobj))
         # Copy file from, to, and with mode unchanged
diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index ed3fc07..464b096 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -206,6 +206,19 @@ class InstallDir(HoldableObject):
         self.install_tag = install_tag
 
 
+class DepManifest:
+
+    def __init__(self, version: str, license: T.List[str]):
+        self.version = version
+        self.license = license
+
+    def to_json(self) -> T.Dict[str, T.Union[str, T.List[str]]]:
+        return {
+            'version': self.version,
+            'license': self.license,
+        }
+
+
 class Build:
     """A class that holds the status of one build including
     all dependencies and so on.
@@ -235,7 +248,7 @@ class Build:
         self.dist_scripts: T.List['ExecutableSerialisation'] = []
         self.install_dirs: T.List[InstallDir] = []
         self.dep_manifest_name: T.Optional[str] = None
-        self.dep_manifest: T.Dict[str, T.Dict[str, T.Any]] = {}  # TODO: what should this dict be?
+        self.dep_manifest: T.Dict[str, DepManifest] = {}
         self.stdlibs = PerMachine({}, {})
         self.test_setups: T.Dict[str, TestSetup] = {}
         self.test_setup_default_name = None
diff --git a/mesonbuild/interpreter/interpreter.py b/mesonbuild/interpreter/interpreter.py
index 1d360eb..c6aafb9 100644
--- a/mesonbuild/interpreter/interpreter.py
+++ b/mesonbuild/interpreter/interpreter.py
@@ -1060,8 +1060,7 @@ external dependencies (including libraries) must go to "dependencies".''')
         if self.build.project_version is None:
             self.build.project_version = self.project_version
         proj_license = mesonlib.stringlistify(kwargs.get('license', 'unknown'))
-        self.build.dep_manifest[proj_name] = {'version': self.project_version,
-                                              'license': proj_license}
+        self.build.dep_manifest[proj_name] = build.DepManifest(self.project_version, proj_license)
         if self.subproject in self.build.projects:
             raise InvalidCode('Second call to project().')
 
diff --git a/mesonbuild/interpreter/mesonmain.py b/mesonbuild/interpreter/mesonmain.py
index 144029c..8c62f87 100644
--- a/mesonbuild/interpreter/mesonmain.py
+++ b/mesonbuild/interpreter/mesonmain.py
@@ -384,14 +384,14 @@ class MesonMain(MesonInterpreterObject):
 
     @noPosargs
     @noKwargs
-    def project_version_method(self, args: T.List['TYPE_var'], kwargs: 'TYPE_kwargs') -> str:
-        return self.build.dep_manifest[self.interpreter.active_projectname]['version']
+    def project_version_method(self, args: T.List['TYPE_var'], kwargs: 'TYPE_kwargs') -> T.List[str]:
+        return self.build.dep_manifest[self.interpreter.active_projectname].version
 
     @FeatureNew('meson.project_license()', '0.45.0')
     @noPosargs
     @noKwargs
     def project_license_method(self, args: T.List['TYPE_var'], kwargs: 'TYPE_kwargs') -> str:
-        return self.build.dep_manifest[self.interpreter.active_projectname]['license']
+        return self.build.dep_manifest[self.interpreter.active_projectname].license
 
     @noPosargs
     @noKwargs
diff --git a/mesonbuild/modules/__init__.py b/mesonbuild/modules/__init__.py
index 8f64120..0129909 100644
--- a/mesonbuild/modules/__init__.py
+++ b/mesonbuild/modules/__init__.py
@@ -45,7 +45,7 @@ class ModuleState:
         self.current_lineno = interpreter.current_lineno
         self.environment = interpreter.environment
         self.project_name = interpreter.build.project_name
-        self.project_version = interpreter.build.dep_manifest[interpreter.active_projectname]
+        self.project_version = interpreter.build.dep_manifest[interpreter.active_projectname].version
         # The backend object is under-used right now, but we will need it:
         # https://github.com/mesonbuild/meson/issues/1419
         self.backend = interpreter.backend
diff --git a/mesonbuild/modules/pkgconfig.py b/mesonbuild/modules/pkgconfig.py
index f73e168..7be4796 100644
--- a/mesonbuild/modules/pkgconfig.py
+++ b/mesonbuild/modules/pkgconfig.py
@@ -12,18 +12,22 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import os
 from pathlib import PurePath
+import os
+import typing as T
 
+from . import ExtensionModule
+from . import ModuleReturnValue
 from .. import build
 from .. import dependencies
-from ..dependencies import ThreadDependency
 from .. import mesonlib
 from .. import mlog
-from . import ModuleReturnValue
-from . import ExtensionModule
+from ..dependencies import ThreadDependency
 from ..interpreterbase import permittedKwargs, FeatureNew, FeatureNewKwargs
 
+if T.TYPE_CHECKING:
+    from . import ModuleState
+
 already_warned_objs = set()
 
 class DependenciesHelper:
@@ -451,8 +455,8 @@ class PkgConfigModule(ExtensionModule):
                       'install_dir', 'extra_cflags', 'variables', 'url', 'd_module_versions',
                       'dataonly', 'conflicts', 'uninstalled_variables',
                       'unescaped_variables', 'unescaped_uninstalled_variables'})
-    def generate(self, state, args, kwargs):
-        default_version = state.project_version['version']
+    def generate(self, state: 'ModuleState', args, kwargs):
+        default_version = state.project_version
         default_install_dir = None
         default_description = None
         default_name = None
diff --git a/mesonbuild/modules/unstable_external_project.py b/mesonbuild/modules/unstable_external_project.py
index 8bd3c1c..87b0ab6 100644
--- a/mesonbuild/modules/unstable_external_project.py
+++ b/mesonbuild/modules/unstable_external_project.py
@@ -232,7 +232,7 @@ class ExternalProject(NewExtensionModule):
             abs_includedir = Path(abs_includedir, subdir)
         abs_libdir = Path(self.install_dir, self.rel_prefix, self.libdir)
 
-        version = self.project_version['version']
+        version = self.project_version
         incdir = []
         compile_args = [f'-I{abs_includedir}']
         link_args = [f'-L{abs_libdir}', f'-l{libname}']