Fix detection of next version in Fabric's CSVLogger (#17986)

src/lightning/fabric/CHANGELOG.md

@@ -174,6 +174,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Fixed an issue with hpu imports leading to performance degradation  ([#17788](https://github.com/Lightning-AI/lightning/pull/17788))
 
 
+- Fixed computing the next version folder in `CSVLogger` ([#17139](https://github.com/Lightning-AI/lightning/pull/17139), [#17139](https://github.com/Lightning-AI/lightning/pull/17986))
+
+
 ## [2.0.3] - 2023-06-07
 
 - Added support for `Callback` registration through entry points ([#17756](https://github.com/Lightning-AI/lightning/pull/17756))

src/lightning/fabric/loggers/csv_logs.py

@@ -105,7 +105,7 @@ def log_dir(self) -> str:
         """
         # create a pseudo standard path
         version = self.version if isinstance(self.version, str) else f"version_{self.version}"
-        return os.path.join(self.root_dir, self.name, version)
+        return os.path.join(self._root_dir, self.name, version)
 
     @property
     @rank_zero_experiment
@@ -120,7 +120,7 @@ def experiment(self) -> "_ExperimentWriter":
         if self._experiment is not None:
             return self._experiment
 
-        os.makedirs(self.root_dir, exist_ok=True)
+        os.makedirs(self._root_dir, exist_ok=True)
         self._experiment = _ExperimentWriter(log_dir=self.log_dir)
         return self._experiment
 
@@ -153,14 +153,14 @@ def finalize(self, status: str) -> None:
         self.save()
 
     def _get_next_version(self) -> int:
-        root_dir = self.root_dir
+        versions_root = os.path.join(self._root_dir, self.name)
 
-        if not self._fs.isdir(root_dir):
-            log.warning("Missing logger folder: %s", root_dir)
+        if not self._fs.isdir(versions_root):
+            log.warning("Missing logger folder: %s", versions_root)
             return 0
 
         existing_versions = []
-        for d in self._fs.listdir(root_dir):
+        for d in self._fs.listdir(versions_root):
             full_path = d["name"]
             name = os.path.basename(full_path)
             if self._fs.isdir(full_path) and name.startswith("version_"):

tests/tests_fabric/loggers/test_csv.py

@@ -21,23 +21,20 @@
 from lightning.fabric.loggers.csv_logs import _ExperimentWriter
 
 
-def test_file_logger_automatic_versioning(tmpdir):
+def test_file_logger_automatic_versioning(tmp_path):
     """Verify that automatic versioning works."""
-    root_dir = tmpdir.mkdir("exp")
-    root_dir.mkdir("version_0")
-    root_dir.mkdir("version_1")
-    logger = CSVLogger(root_dir=root_dir, name="exp")
+    (tmp_path / "exp" / "version_0").mkdir(parents=True)
+    (tmp_path / "exp" / "version_1").mkdir()
+    logger = CSVLogger(root_dir=tmp_path, name="exp")
     assert logger.version == 2
 
 
-def test_file_logger_automatic_versioning_relative_root_dir(tmpdir, monkeypatch):
+def test_file_logger_automatic_versioning_relative_root_dir(tmp_path, monkeypatch):
     """Verify that automatic versioning works, when root_dir is given a relative path."""
-    root_dir = tmpdir.mkdir("exp")
-    logs_dir = root_dir.mkdir("logs")
-    logs_dir.mkdir("version_0")
-    logs_dir.mkdir("version_1")
-    monkeypatch.chdir(tmpdir)
-    logger = CSVLogger(root_dir="exp/logs", name="logs")
+    (tmp_path / "exp" / "logs" / "version_0").mkdir(parents=True)
+    (tmp_path / "exp" / "logs" / "version_1").mkdir()
+    monkeypatch.chdir(tmp_path)
+    logger = CSVLogger(root_dir="exp", name="logs")
     assert logger.version == 2
 
 
@@ -71,7 +68,7 @@ def test_file_logger_no_name(tmpdir, name):
     logger = CSVLogger(root_dir=tmpdir, name=name)
     logger.log_metrics({"a": 1})
     logger.save()
-    assert os.path.normpath(logger.root_dir) == tmpdir  # use os.path.normpath to handle trailing /
+    assert os.path.normpath(logger._root_dir) == tmpdir  # use os.path.normpath to handle trailing /
     assert os.listdir(tmpdir / "version_0")