ensure that config file paths are absolute

WEST_CONFIG_* environment variables require absolute paths for their
specified config files to ensure independency from the current working
directory.

Author: thorsten-klein

src/west/configuration.py

@@ -78,6 +78,8 @@ def from_path(path: Path | list[Path] | None) -> '_InternalCF | None':
         paths = path
         if isinstance(paths, Path):
             paths = [Path(p) for p in str(paths).split(os.pathsep)]
+        if not all([p.is_absolute() for p in paths]):
+            raise WestNotFound(f"config file path(s) must be absolute: '{paths_to_str(paths)}'")
         paths = [p for p in paths if p.exists()]
         return _InternalCF(paths) if paths else None
 

tests/test_config.py

@@ -590,6 +590,29 @@ def test_config_precedence():
     assert cfg(f=LOCAL)['pytest']['precedence'] == 'local'
 
 
+TEST_CASES_CONFIG_RELATIVE = [
+    # (flag, env_var)
+    ('--local', 'WEST_CONFIG_LOCAL'),
+    ('--system', 'WEST_CONFIG_SYSTEM'),
+    ('--global', 'WEST_CONFIG_GLOBAL'),
+]
+
+
+@pytest.mark.parametrize("test_case", TEST_CASES_CONFIG_RELATIVE)
+def test_config_relative_paths(test_case, config_tmpdir):
+    flag, env_var = test_case
+
+    # one relative config file path is specified
+    os.environ[env_var] = 'config1'
+    stderr = cmd_raises(f'config {flag} some.key', subprocess.CalledProcessError)
+    assert f"config file path(s) must be absolute: '{os.environ[env_var]}'" in stderr
+
+    # one of multiple config file paths is relative
+    os.environ[env_var] = f'config1{os.pathsep}config2'
+    stderr = cmd_raises(f'config {flag} some.key', subprocess.CalledProcessError)
+    assert f"config file path(s) must be absolute: '{os.environ[env_var]}'" in stderr
+
+
 def test_config_multiple(config_tmpdir):
     # Verify that local settings take precedence over global ones,
     # but that both values are still available, and that setting