Return absolute path without resolving symlinks (#4341)

After the rewrite of `util.abs_path` to use `pathlib` instead of
`os.path` (000d200,
c20dc08) the function now resolves
symlinks in the given path whereas it did not do before.
This breaks setups where the `molecule.yml` file in a scenario is a
symlink. E.g.

/common-files/molecule.yml
/roles/role1/molecule/default/molecule.yml -> /common-files/molecule.yml
/roles/role1/molecule/some-scenario/molecule.yml ->
/common-files/molecule.yml
/roles/role2/molecule/default/molecule.yml -> /common-files/molecule.yml

Where a common `molecule.yml` can be used for multiple roles / scenarios
and where changes to this file should reflect everywhere.

In this case `molecule test` executed in `/roles/role1` returns
`Scenario 'default' not found. Exiting.` or `molecule test -s
some-scenario` executed in `/roles/role1` returns `Scenario
'some-scenario' not found. Exiting.` (see
https://github.com/ansible/molecule/blob/f58ac30d5cee79a073ce0893701c8e82ec669078/src/molecule/scenarios.py#L127)

Unfortunately `pathlib` is not a drop-in replacement for `os.path` (see
https://docs.python.org/3/library/pathlib.html#comparison-to-the-os-and-os-path-modules).


[Path.absolute()](https://docs.python.org/3/library/pathlib.html#pathlib.Path.absolute)
does not resolve symlink but does not reduce `/../` segments in the
path.
[Path.resolve()](https://docs.python.org/3/library/pathlib.html#pathlib.Path.resolve)
does reduce `/../` path elements, but also resolves symlinks.

There is no method or combination of methods in the `Path` object that
can deliver the same functionality as
[os.path.abspath()](https://docs.python.org/3/library/os.path.html#os.path.abspath).
Hence the code reverts back to using `os.path.abspath()`, but keeps
accepting `Path` objects as input and returns the absolute path as such
in these cases.

---------

Signed-off-by: Ruediger Pluem <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Kate Case <[email protected]>

src/molecule/util.py

@@ -402,7 +402,7 @@ def abs_path(path: str | Path | None) -> str | Path:
     """Return absolute path.
 
     Args:
-        path: File path to resolve absolute path from.
+        path: File path to create absolute path from.
 
     Returns:
         Absolute path of path.
@@ -411,9 +411,9 @@ def abs_path(path: str | Path | None) -> str | Path:
         return ""
 
     output_type = type(path)
-    if isinstance(path, str):
-        path = Path(path)
-    path = path.resolve()
+    if isinstance(path, Path):
+        path = str(path)
+    path = os.path.abspath(path)  # noqa: PTH100
 
     return output_type(path)
 

tests/unit/test_util.py

@@ -21,6 +21,7 @@
 
 import binascii
 import os
+import tempfile
 import warnings
 
 from pathlib import Path
@@ -340,6 +341,17 @@ def test_abs_path_with_empty_path() -> None:
     assert util.abs_path("") == ""
 
 
+def test_abs_path_with_symlink() -> None:
+    """Test the `abs_path` function not resolving symlinks."""
+    with tempfile.NamedTemporaryFile() as tmp_file:
+        tmpfile_path = Path(tmp_file.name)
+        symlink_path = Path(tmp_file.name + "_sym")
+        symlink_path.symlink_to(tmpfile_path)
+        abs_path_result = util.abs_path(symlink_path)
+        symlink_path.unlink()
+    assert abs_path_result == symlink_path
+
+
 @pytest.mark.parametrize(
     ("a", "b", "x"),
     [  # noqa: PT007