feature: add new "lazy-wheel" config option

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, lambda val: str(val)),
             "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

@@ -32,6 +32,8 @@
 
     from poetry.core.packages.project_package import ProjectPackage
 
+    from poetry.inspection.lazy_wheel import MemoryWheel
+
 
 logger = logging.getLogger(__name__)
 
@@ -231,9 +233,7 @@ def to_package(
         return package
 
     @classmethod
-    def _from_distribution(
-        cls, dist: pkginfo.BDist | pkginfo.SDist | pkginfo.Wheel
-    ) -> PackageInfo:
+    def _from_distribution(cls, dist: pkginfo.Distribution) -> PackageInfo:
         """
         Helper method to parse package information from a `pkginfo.Distribution`
         instance.
@@ -244,7 +244,7 @@ def _from_distribution(
 
         if dist.requires_dist:
             requirements = list(dist.requires_dist)
-        else:
+        elif isinstance(dist, (pkginfo.BDist, pkginfo.SDist, pkginfo.Wheel)):
             requires = Path(dist.filename) / "requires.txt"
             if requires.exists():
                 text = requires.read_text(encoding="utf-8")
@@ -258,8 +258,9 @@ def _from_distribution(
             requires_python=dist.requires_python,
         )
 
-        info._source_type = "file"
-        info._source_url = Path(dist.filename).resolve().as_posix()
+        if isinstance(dist, (pkginfo.BDist, pkginfo.SDist, pkginfo.Wheel)):
+            info._source_type = "file"
+            info._source_url = Path(dist.filename).resolve().as_posix()
 
         return info
 
@@ -522,6 +523,15 @@ def from_wheel(cls, path: Path) -> PackageInfo:
         except ValueError:
             return PackageInfo()
 
+    @classmethod
+    def from_memory_wheel(cls, wheel: MemoryWheel) -> PackageInfo:
+        """
+        Gather package information from a partial fetched wheel kept in memory.
+
+        :param path: Path to wheel.
+        """
+        return cls._from_distribution(wheel)
+
     @classmethod
     def from_bdist(cls, path: Path) -> PackageInfo:
         """