Allow merging requirement specs

When a package defines requirements based on self version constraints,
allow those definitions to overlap and the result is a sum of all
requirements matching all constraints.

metapkg/packages/__init__.py

@@ -17,6 +17,7 @@
     PkgConfigMeta,
     canonicalize_name,
     get_bundled_pkg,
+    merge_requirements,
     pep440_to_semver,
     semver_pre_tag,
 )
@@ -49,6 +50,7 @@
     "PkgConfigMeta",
     "canonicalize_name",
     "get_bundled_pkg",
+    "merge_requirements",
     "pep440_to_semver",
     "semver_pre_tag",
     "BaseSource",

metapkg/packages/base.py

@@ -437,6 +437,22 @@ class PkgConfigMeta:
 
 BundledPackage_T = TypeVar("BundledPackage_T", bound="BundledPackage")
 
+RequirementsSpec = Union[
+    list[str | poetry_dep.Dependency],
+    Mapping[
+        str,
+        list[str],
+    ],
+    Mapping[
+        str,
+        list[str | poetry_dep.Dependency],
+    ],
+    Mapping[
+        poetry_constr.VersionConstraint,
+        list[str | poetry_dep.Dependency],
+    ],
+]
+
 
 class BundledPackage(BasePackage):
     ident: ClassVar[str]
@@ -450,21 +466,8 @@ class BundledPackage(BasePackage):
 
     source_version: str
 
-    artifact_requirements: Union[
-        list[str | poetry_dep.Dependency],
-        dict[
-            str | poetry_constr.VersionConstraint,
-            list[str | poetry_dep.Dependency],
-        ],
-    ] = []
-    artifact_build_requirements: Union[
-        list[str | poetry_dep.Dependency],
-        dict[
-            str | poetry_constr.VersionConstraint,
-            list[str | poetry_dep.Dependency],
-        ],
-    ] = []
-
+    artifact_requirements: RequirementsSpec = []
+    artifact_build_requirements: RequirementsSpec = []
     build_requires: list[poetry_dep.Dependency]
 
     options: dict[str, Any]
@@ -907,15 +910,14 @@ def _get_requirements(
                 if isinstance(ver, str):
                     ver = poetry_constr.parse_constraint(ver)
                 if ver.allows(self.version):
-                    req_spec = ver_reqs
-                    break
-            else:
-                if spec:
-                    raise RuntimeError(
-                        f"{prop} for {self.name!r} are not "
-                        f"empty, but don't match the requested version "
-                        f"{self.version}"
-                    )
+                    req_spec.extend(ver_reqs)
+
+            if not req_spec and spec:
+                raise RuntimeError(
+                    f"{prop} for {self.name!r} are not "
+                    f"empty, but don't match the requested version "
+                    f"{self.version}"
+                )
         else:
             req_spec = spec
 
@@ -1218,6 +1220,19 @@ def set_metadata_tags(self, tags: Mapping[str, str]) -> None:
         self.metadata_tags = dict(tags)
 
 
+def merge_requirements(
+    *specs: RequirementsSpec,
+) -> RequirementsSpec:
+    result = collections.defaultdict(list)
+    for spec in specs:
+        if isinstance(spec, list):
+            result["*"].extend(spec)
+        else:
+            for k, v in spec.items():
+                result[k].extend(v)
+    return dict(result)
+
+
 @functools.cache
 def _get_bundled_pkg_config_meta(name: str) -> PkgConfigMeta:
     package = _get_pkg_in_bundle_repo(poetry_dep.Dependency(name, "*"))