Fix relativized readers reading a CWD-relative path instead of the store's file

aiofiledol/__init__.py

@@ -6,7 +6,9 @@
 import asyncio
 import os
 
+from dol import wrapped_self
 from dol.base import KvReader, KvPersister
+from dol.dig import inner_most_key
 from dol.paths import mk_relative_path_store
 from dol.filesys import (
     FileCollection,
@@ -22,6 +24,22 @@
 _dflt_not_found_error_msg = "Key not found: {}"
 
 
+def _resolve_key(store, k):
+    """The leaf-level filepath for ``k``, resolved through any wrapping layers.
+
+    ``mk_relative_path_store`` (and dol's wrapping machinery generally) wraps by
+    delegation: a method defined on the wrapped class is reached bound to the INNER
+    store, but with the OUTER, un-transformed key. Handing that key straight to
+    ``AIOFile`` would resolve it against the process CWD instead of ``rootdir``.
+    Walking the wrapper chain with ``inner_most_key`` recovers the real filepath.
+
+    This REPLACES ``store._id_of_key(k)`` -- it walks the whole chain including the
+    leaf, so the two must never be composed. For an un-wrapped store no layer defines
+    ``_id_of_key`` and ``k`` is returned verbatim.
+    """
+    return inner_most_key(wrapped_self(store), k, default=k)
+
+
 class AioFileBytesReader(FileCollection, KvReader):
     _read_open_kwargs = dict(mode="rb")
 
@@ -46,7 +64,7 @@ async def aget(self, k):  # noqa
         b'hello world'
         """
 
-        async with AIOFile(k, **self._read_open_kwargs) as fp:
+        async with AIOFile(_resolve_key(self, k), **self._read_open_kwargs) as fp:
             v = await fp.read()  # Question: Is it faster if we just did `return await fp.read(), instead of assign?
         return v
         # with open(k, **self._read_open_kwargs) as fp:
@@ -102,7 +120,7 @@ async def asetitem(self, k, v):
         >>> asyncio.run(s.aget(k))  # read it back (async reader; __getitem__ is disabled)
         b'bar'
         """
-        async with AIOFile(k, **self._write_open_kwargs) as fp:
+        async with AIOFile(_resolve_key(self, k), **self._write_open_kwargs) as fp:
             await fp.write(v)
             await fp.fsync()
 

aiofiledol/tests/__init__.py

@@ -0,0 +1 @@
+"""Tests for aiofiledol"""

aiofiledol/tests/test_relative_path_keys.py

@@ -0,0 +1,75 @@
+"""Tests that relativized stores read the file they advertise, not a CWD lookalike.
+
+``mk_relative_path_store`` wraps by delegation, so a method defined on the wrapped
+class (such as ``aget``) is reached bound to the INNER store while still receiving
+the OUTER, un-transformed key. Passing that relative key straight to ``AIOFile``
+resolves it against the process CWD instead of the store's ``rootdir`` -- silently
+returning the wrong bytes when a same-named file happens to sit in the CWD, and
+raising ``FileNotFoundError`` for a key the store just enumerated when it does not.
+"""
+
+import asyncio
+import os
+
+from aiofiledol import (
+    AioFileBytesReader,
+    RelPathAioFileBytesReader,
+    RelPathFileStringReader,
+)
+
+KEY = "greeting"
+REAL = b"REAL STORE CONTENT"
+DECOY = b"DECOY FROM CWD"
+
+
+def _store_dir(tmp_path, name, content=None):
+    """Make a directory under ``tmp_path``, optionally holding a ``KEY`` file.
+
+    Returns the path with a trailing separator -- what the relativized stores want,
+    so that the keys they yield carry no leading separator.
+    """
+    d = tmp_path / name
+    d.mkdir()
+    if content is not None:
+        mode = "wb" if isinstance(content, bytes) else "wt"
+        with open(d / KEY, mode) as fp:
+            fp.write(content)
+    return str(d) + os.sep
+
+
+def test_relpath_aget_reads_the_store_not_the_cwd(tmp_path, monkeypatch):
+    """A relative key must resolve against ``rootdir``, never against the CWD."""
+    rootdir = _store_dir(tmp_path, "realstore", REAL)
+    monkeypatch.chdir(_store_dir(tmp_path, "decoy", DECOY))
+
+    s = RelPathAioFileBytesReader(rootdir)
+    assert asyncio.run(s.aget(KEY)) == REAL
+
+
+def test_relpath_aget_finds_every_key_it_enumerates(tmp_path, monkeypatch):
+    """Every key the store yields must be readable -- no ``FileNotFoundError``."""
+    rootdir = _store_dir(tmp_path, "realstore", REAL)
+    monkeypatch.chdir(_store_dir(tmp_path, "elsewhere"))
+
+    s = RelPathAioFileBytesReader(rootdir)
+    assert list(s) == [KEY]
+    for k in s:
+        assert asyncio.run(s.aget(k)) == REAL
+
+
+def test_relpath_string_reader_too(tmp_path, monkeypatch):
+    """The text-mode relativized reader inherits the same ``aget``, so same rule."""
+    rootdir = _store_dir(tmp_path, "realstore", REAL.decode())
+    monkeypatch.chdir(_store_dir(tmp_path, "decoy", DECOY.decode()))
+
+    s = RelPathFileStringReader(rootdir)
+    assert asyncio.run(s.aget(KEY)) == REAL.decode()
+
+
+def test_bare_reader_still_takes_absolute_keys(tmp_path, monkeypatch):
+    """Regression guard: an un-wrapped store keeps its absolute-key behaviour."""
+    rootdir = _store_dir(tmp_path, "realstore", REAL)
+    monkeypatch.chdir(_store_dir(tmp_path, "elsewhere"))
+
+    s = AioFileBytesReader(rootdir, max_levels=0)
+    assert asyncio.run(s.aget(os.path.join(rootdir, KEY))) == REAL