[1.2] feat: forward compatibility for lock file format 2.0 (#6608)

Backport the ability to read 2.0 lockfiles per #6393

src/poetry/packages/locker.py

@@ -109,8 +109,9 @@ def locked_repository(self) -> Repository:
             if source_type in ["directory", "file"]:
                 url = self._lock.path.parent.joinpath(url).resolve().as_posix()
 
+            name = info["name"]
             package = Package(
-                info["name"],
+                name,
                 info["version"],
                 info["version"],
                 source_type=source_type,
@@ -123,8 +124,19 @@ def locked_repository(self) -> Repository:
             package.category = info.get("category", "main")
             package.optional = info["optional"]
             metadata = cast("dict[str, Any]", lock_data["metadata"])
-            name = info["name"]
-            if "hashes" in metadata:
+
+            # Storing of package files and hashes has been through a few generations in
+            # the lockfile, we can read them all:
+            #
+            # - latest and preferred is that this is read per package, from
+            #   package.files
+            # - oldest is that hashes were stored in metadata.hashes without filenames
+            # - in between those two, hashes were stored alongside filenames in
+            #   metadata.files
+            package_files = info.get("files")
+            if package_files is not None:
+                package.files = package_files
+            elif "hashes" in metadata:
                 # Old lock so we create dummy files from the hashes
                 hashes = cast("dict[str, Any]", metadata["hashes"])
                 package.files = [{"name": h, "hash": h} for h in hashes[name]]
@@ -288,6 +300,12 @@ def _get_lock_data(self) -> TOMLDocument:
 
         metadata = cast("Table", lock_data["metadata"])
         lock_version = Version.parse(metadata.get("lock-version", "1.0"))
+
+        # As a special case: the ability to read a 2.0 lockfile was backported and is
+        # fully supported.
+        if lock_version == Version.parse("2.0"):
+            return lock_data
+
         current_version = Version.parse(self._VERSION)
         # We expect the locker to be able to read lock files
         # from the same semantic versioning range

tests/packages/test_locker.py

@@ -700,14 +700,52 @@ def test_locker_should_emit_warnings_if_lock_version_is_newer_but_allowed(
     assert record.message == expected
 
 
-def test_locker_should_raise_an_error_if_lock_version_is_newer_and_not_allowed(
+def test_locker_can_read_2_0_lockfile_because_backported(
     locker: Locker, caplog: LogCaptureFixture
 ):
     content = """\
+[[package]]
+name = "demo"
+version = "1.0"
+description = ""
+category = "main"
+optional = false
+python-versions = "*"
+develop = false
+files = [
+    {file = "demo-1.0-cp39-win_amd64.whl", hash = "sha256"},
+    {file = "demo-1.0.tar.gz", hash = "sha256"},
+    {file = "demo-1.0-py3-none-any.whl", hash = "sha256"},
+]
+
 [metadata]
 lock-version = "2.0"
 python-versions = "~2.7 || ^3.4"
 content-hash = "c3d07fca33fba542ef2b2a4d75bf5b48d892d21a830e2ad9c952ba5123a52f77"
+"""
+    caplog.set_level(logging.WARNING, logger="poetry.packages.locker")
+
+    locker.lock.write(tomlkit.parse(content))
+
+    repository = locker.locked_repository()
+    packages = repository.packages
+    assert len(packages) == 1
+    package = packages[0]
+    assert package.files == [
+        {"file": "demo-1.0-cp39-win_amd64.whl", "hash": "sha256"},
+        {"file": "demo-1.0.tar.gz", "hash": "sha256"},
+        {"file": "demo-1.0-py3-none-any.whl", "hash": "sha256"},
+    ]
+
+
+def test_locker_should_raise_an_error_if_lock_version_is_newer_and_not_allowed(
+    locker: Locker, caplog: LogCaptureFixture
+):
+    content = """\
+[metadata]
+lock-version = "2.1"
+python-versions = "~2.7 || ^3.4"
+content-hash = "c3d07fca33fba542ef2b2a4d75bf5b48d892d21a830e2ad9c952ba5123a52f77"
 
 [metadata.files]
 """