upgrade extremely useful (and easy to miss) warning to an error

CHANGELOG.md

@@ -3,6 +3,10 @@
 
 ## [1.7.1] - 2023-11-16
 
+### Added
+
+- Raise an error when lock file is outdated during `install` ([#8737](https://github.com/python-poetry/poetry/pull/8737)).
+
 ### Fixed
 
 - Fix an issue where sdists that call CLI tools of their build requirements could not be installed ([#8630](https://github.com/python-poetry/poetry/pull/8630)).

src/poetry/installation/installer.py

@@ -245,12 +245,12 @@ def _do_install(self) -> int:
  locked_repository = self._locker.locked_repository()
 
  if not self._locker.is_fresh():
- self._io.write_error_line(
- "<warning>"
- "Warning: poetry.lock is not consistent with pyproject.toml. "
+ raise ValueError(
+ "<error>"
+ "Error: poetry.lock is not consistent with pyproject.toml. "
  "You may be getting improper dependencies. "
  "Run `poetry lock [--no-update]` to fix it."
- "</warning>"
+ "</error>"
  )
 
  locker_extras = {

tests/installation/test_installer.py

@@ -2,6 +2,7 @@
 
 import json
 
+import re
 from pathlib import Path
 from typing import TYPE_CHECKING
 from typing import Any
@@ -97,6 +98,7 @@ def __init__(self, lock_path: Path) -> None:
  self._lock = lock_path / "poetry.lock"
  self._written_data = None
  self._locked = False
+ self._fresh = True
  self._lock_data = None
  self._content_hash = self._get_content_hash()
 
@@ -121,8 +123,13 @@ def mock_lock_data(self, data: dict[str, Any]) -> None:
  def is_locked(self) -> bool:
  return self._locked
 
+ def fresh(self, is_fresh: bool = True) -> Locker:
+ self._fresh = is_fresh
+
+ return self
+
  def is_fresh(self) -> bool:
- return True
+ return self._fresh
 
  def _get_content_hash(self) -> str:
  return "123456789"
@@ -208,6 +215,19 @@ def test_run_no_dependencies(installer: Installer, locker: Locker) -> None:
  assert locker.written_data == expected
 
 
+def test_not_fresh_lock(installer: Installer, locker: Locker) -> None:
+ locker.locked().fresh(False)
+ with pytest.raises(
+ ValueError,
+ match=re.escape(
+ "<error>Error: poetry.lock is not consistent with pyproject.toml. You may"
+ " be getting improper dependencies. Run `poetry lock [--no-update]` to fix"
+ " it.</error>"
+ ),
+ ):
+ installer.run()
+
+
 def test_run_with_dependencies(
  installer: Installer, locker: Locker, repo: Repository, package: ProjectPackage
 ) -> None: