feature: add new "lazy-wheel" config option (#8815)

If active and a server supports range requests, we do not have to download entire wheels to fetch metadata but can just download the METADATA file from the remote wheel with a couple of range requests.

docs/configuration.md

@@ -271,6 +271,23 @@ across all your projects if incorrectly set.
 
 Use parallel execution when using the new (`>=1.1.0`) installer.
 
+### `solver.lazy-wheel`
+
+**Type**: `boolean`
+
+**Default**: `true`
+
+**Environment Variable**: `POETRY_SOLVER_LAZY_WHEEL`
+
+*Introduced in 1.8.0*
+
+Do not download entire wheels to extract metadata but use
+[HTTP range requests](https://developer.mozilla.org/en-US/docs/Web/HTTP/Range_requests)
+to only download the METADATA files of wheels.
+Especially with slow network connections this setting can speed up dependency resolution significantly.
+If the cache has already been filled or the server does not support HTTP range requests,
+this setting makes no difference.
+
 ### `virtualenvs.create`
 
 **Type**: `boolean`

src/poetry/config/config.py

@@ -131,6 +131,9 @@ class Config:
             "max-workers": None,
             "no-binary": None,
         },
+        "solver": {
+            "lazy-wheel": True,
+        },
         "warnings": {
             "export": True,
         },
@@ -296,6 +299,7 @@ def _get_normalizer(name: str) -> Callable[[str], Any]:
             "experimental.system-git-client",
             "installer.modern-installation",
             "installer.parallel",
+            "solver.lazy-wheel",
             "warnings.export",
         }:
             return boolean_normalizer

src/poetry/console/commands/config.py

@@ -68,15 +68,16 @@ def unique_config_values(self) -> dict[str, tuple[Any, Any]]:
             ),
             "virtualenvs.path": (str, lambda val: str(Path(val))),
             "virtualenvs.prefer-active-python": (boolean_validator, boolean_normalizer),
+            "virtualenvs.prompt": (str, str),
             "experimental.system-git-client": (boolean_validator, boolean_normalizer),
             "installer.modern-installation": (boolean_validator, boolean_normalizer),
             "installer.parallel": (boolean_validator, boolean_normalizer),
             "installer.max-workers": (lambda val: int(val) > 0, int_normalizer),
-            "virtualenvs.prompt": (str, lambda val: str(val)),
             "installer.no-binary": (
                 PackageFilterPolicy.validator,
                 PackageFilterPolicy.normalize,
             ),
+            "solver.lazy-wheel": (boolean_validator, boolean_normalizer),
             "warnings.export": (boolean_validator, boolean_normalizer),
         }
 

src/poetry/inspection/info.py

@@ -30,6 +30,7 @@
 if TYPE_CHECKING:
     from collections.abc import Iterator
 
+    from packaging.metadata import RawMetadata
     from poetry.core.packages.project_package import ProjectPackage
 
 
@@ -392,7 +393,22 @@ def _find_dist_info(path: Path) -> Iterator[Path]:
             yield Path(d)
 
     @classmethod
-    def from_metadata(cls, path: Path) -> PackageInfo | None:
+    def from_metadata(cls, metadata: RawMetadata) -> PackageInfo:
+        """
+        Create package information from core metadata.
+
+        :param metadata: raw metadata
+        """
+        return cls(
+            name=metadata.get("name"),
+            version=metadata.get("version"),
+            summary=metadata.get("summary"),
+            requires_dist=metadata.get("requires_dist"),
+            requires_python=metadata.get("requires_python"),
+        )
+
+    @classmethod
+    def from_metadata_directory(cls, path: Path) -> PackageInfo | None:
         """
         Helper method to parse package information from an unpacked metadata directory.
 
@@ -474,7 +490,7 @@ def from_directory(cls, path: Path, disable_build: bool = False) -> PackageInfo:
         if project_package:
             info = cls.from_package(project_package)
         else:
-            info = cls.from_metadata(path)
+            info = cls.from_metadata_directory(path)
 
             if not info or info.requires_dist is None:
                 try:
@@ -583,7 +599,7 @@ def get_pep517_metadata(path: Path) -> PackageInfo:
                 *PEP517_META_BUILD_DEPS,
             )
             venv.run_python_script(pep517_meta_build_script)
-            info = PackageInfo.from_metadata(dest_dir)
+            info = PackageInfo.from_metadata_directory(dest_dir)
         except EnvCommandError as e:
             # something went wrong while attempting pep517 metadata build
             # fallback to egg_info if setup.py available
@@ -600,7 +616,7 @@ def get_pep517_metadata(path: Path) -> PackageInfo:
             os.chdir(path)
             try:
                 venv.run("python", "setup.py", "egg_info")
-                info = PackageInfo.from_metadata(path)
+                info = PackageInfo.from_metadata_directory(path)
             except EnvCommandError as fbe:
                 raise PackageInfoError(
                     path, e, "Fallback egg_info generation failed.", fbe