Fix compatibility check for lock files (#2717)

poetry/packages/locker.py

@@ -234,8 +234,10 @@ def _get_lock_data(self): # type: () -> dict
 
  lock_version = Version.parse(lock_data["metadata"].get("lock-version", "1.0"))
  current_version = Version.parse(self._VERSION)
+ # We expect the locker to be able to read lock files
+ # from the same semantic versioning range
  accepted_versions = parse_constraint(
- "^{}".format(Version(current_version.major, current_version.minor))
+ "^{}".format(Version(current_version.major, 0))
  )
  lock_version_allowed = accepted_versions.allows(lock_version)
  if lock_version_allowed and current_version < lock_version:

tests/packages/test_locker.py

@@ -340,3 +340,29 @@ def test_extras_dependencies_are_ordered(locker, root):
  content = f.read()
 
  assert expected == content
+
+
+def test_locker_should_neither_emit_warnings_nor_raise_error_for_lower_compatible_versions(
+ locker, caplog
+):
+ current_version = Version.parse(Locker._VERSION)
+ older_version = ".".join(
+ [str(current_version.major), str(current_version.minor - 1)]
+ )
+ content = """\
+[metadata]
+content-hash = "c3d07fca33fba542ef2b2a4d75bf5b48d892d21a830e2ad9c952ba5123a52f77"
+lock-version = "{version}"
+python-versions = "~2.7 || ^3.4"
+
+[metadata.files]
+""".format(
+ version=older_version
+ )
+ caplog.set_level(logging.WARNING, logger="poetry.packages.locker")
+
+ locker.lock.write(tomlkit.parse(content))
+
+ _ = locker.lock_data
+
+ assert 0 == len(caplog.records)