Improves hash mismatch exception language (#4573)

* Improves wording of exception when calculated hash absent from lockfile and
extracts archive hashing and validation to a separate method

I think this could be further improved by representing the hashes as
a dataclass containing the hash type and the string digest. The types of
hashes would be more robust then instead of hardcoding sha256 here and
in `FileDependency.hash()`. It would also enable enumeration of
hash types of known hashes so that `FileDependency.hash()` could return
a list of hashes based on requested types.

Doing this might alleviate the md5/sha256 problems arising from changes
in poetry-core 1.0.6+ that affect Poetry 1.1.7+ users using Artifactory.

Co-authored-by: Arun Babu Neelicattu <arun.neelicattu@gmail.com>

poetry/installation/executor.py

@@ -17,6 +17,7 @@ from typing import Union
 from cleo.io.null_io import NullIO
 
 from poetry.core.packages.file_dependency import FileDependency
+from poetry.core.packages.package import Package
 from poetry.core.packages.utils.link import Link
 from poetry.core.pyproject.toml import PyProjectTOML
 from poetry.utils._compat import decode
@@ -38,7 +39,6 @@ if TYPE_CHECKING:
     from cleo.io.io import IO  # noqa
 
     from poetry.config.config import Config
-    from poetry.core.packages.package import Package
     from poetry.repositories import Pool
     from poetry.utils.env import Env
 
@@ -671,21 +671,27 @@ class Executor:
                 archive = self._chef.prepare(archive)
 
         if package.files:
-            archive_hash = (
-                "sha256:"
-                + FileDependency(
+            archive_hash = self._validate_archive_hash(archive, package)
+
+            self._hashes[package.name] = archive_hash
+
+        return archive
+
+    @staticmethod
+    def _validate_archive_hash(archive: Path, package: Package) -> str:
+        file_dep = FileDependency(
             package.name,
             Path(archive.path) if isinstance(archive, Link) else archive,
-                ).hash()
         )
-            if archive_hash not in {f["hash"] for f in package.files}:
+        archive_hash = "sha256:" + file_dep.hash()
+        known_hashes = {f["hash"] for f in package.files}
+
+        if archive_hash not in known_hashes:
             raise RuntimeError(
-                    f"Invalid hash for {package} using archive {archive.name}"
+                f"Hash for {package} from archive {archive.name} not found in known hashes (was: {archive_hash})"
             )
 
-            self._hashes[package.name] = archive_hash
-
-        return archive
+        return archive_hash
 
     def _download_archive(self, operation: Union[Install, Update], link: Link) -> Path:
         response = self._authenticator.request(