Update CladeTime tree_as_of and sequence_as_of date handling

Resolve #33

pyproject.toml

@@ -56,6 +56,7 @@ build-backend = "setuptools.build_meta"
 [tool.pytest.ini_options]
 tmp_path_retention_policy = "none"
 filterwarnings = [
+    "ignore::cladetime.exceptions.CladeTimeFutureDateWarning",
     "ignore::DeprecationWarning",
     'ignore:polars found a filename',
 ]

src/cladetime/cladetime.py

@@ -1,11 +1,12 @@
 """Class for clade time traveling."""
 
+import warnings
 from datetime import datetime, timezone
 
 import polars as pl
 import structlog
 
-from cladetime.exceptions import CladeTimeInvalidDateError, CladeTimeInvalidURLError
+from cladetime.exceptions import CladeTimeFutureDateWarning, CladeTimeInvalidDateError, CladeTimeInvalidURLError
 from cladetime.util.config import Config
 from cladetime.util.reference import _get_s3_object_url
 from cladetime.util.sequence import _get_ncov_metadata, get_covid_genome_metadata
@@ -54,12 +55,12 @@ def __init__(self, sequence_as_of=None, tree_as_of=None):
         tree_as_of : datetime | str | None, default = now()
             Use the NextStrain reference tree that was available as of this date.
             Can be a datetime object, a string in the format
-            "YYYY-MM-DD", or None (which defaults to the current date and time).
+            "YYYY-MM-DD", or None (which defaults to the sequence_as_of date).
         """
 
         self._config = self._get_config()
-        self.sequence_as_of = self._validate_as_of_date(sequence_as_of)
-        self.tree_as_of = self._validate_as_of_date(tree_as_of)
+        self.sequence_as_of = sequence_as_of
+        self.tree_as_of = tree_as_of
         self._ncov_metadata = {}
         self._sequence_metadata = pl.LazyFrame()
 
@@ -78,13 +79,54 @@ def __init__(self, sequence_as_of=None, tree_as_of=None):
         else:
             self.url_ncov_metadata = None
 
+    @property
+    def sequence_as_of(self) -> datetime:
+        return self._sequence_as_of
+
+    @sequence_as_of.setter
+    def sequence_as_of(self, date) -> None:
+        """Set the sequence_as_of attribute."""
+        if date is None:
+            sequence_as_of = datetime.now()
+        sequence_as_of = self._validate_as_of_date(date)
+        utc_now = datetime.now().replace(tzinfo=timezone.utc)
+        if sequence_as_of > utc_now:
+            warnings.warn(
+                f"specified sequence_as_of is in the future, defaulting to current time: {utc_now}",
+                category=CladeTimeFutureDateWarning,
+            )
+            sequence_as_of = utc_now
+
+        self._sequence_as_of = sequence_as_of
+
+    @property
+    def tree_as_of(self) -> datetime:
+        return self._tree_as_of
+
+    @tree_as_of.setter
+    def tree_as_of(self, date) -> None:
+        """Set the tree_as_of attribute."""
+        if date is None:
+            tree_as_of = self.sequence_as_of
+        else:
+            tree_as_of = self._validate_as_of_date(date)
+        utc_now = datetime.now().replace(tzinfo=timezone.utc)
+        if tree_as_of > utc_now:
+            warnings.warn(
+                f"specified tree_as_of is in the future, defaulting to sequence_as_of: {self.sequence_as_of}",
+                category=CladeTimeFutureDateWarning,
+            )
+            tree_as_of = self.sequence_as_of
+
+        self._tree_as_of = tree_as_of
+
     @property
     def ncov_metadata(self):
         return self._ncov_metadata
 
     @ncov_metadata.getter
     def ncov_metadata(self) -> dict:
-        """Set the ncov_metadata attribute."""
+        """Get the ncov_metadata attribute."""
         if self.url_ncov_metadata:
             metadata = _get_ncov_metadata(self.url_ncov_metadata)
             return metadata
@@ -98,13 +140,12 @@ def sequence_metadata(self):
 
     @sequence_metadata.getter
     def sequence_metadata(self) -> pl.LazyFrame:
-        """Set the sequence_metadata attribute."""
+        """Get the sequence_metadata attribute."""
         if self.url_sequence_metadata:
             sequence_metadata = get_covid_genome_metadata(metadata_url=self.url_sequence_metadata)
             return sequence_metadata
         else:
             raise CladeTimeInvalidURLError("CladeTime is missing url_sequence_metadata")
-        return sequence_metadata
 
     def __repr__(self):
         return f"CladeTime(sequence_as_of={self.sequence_as_of}, tree_as_of={self.tree_as_of})"
@@ -121,7 +162,7 @@ def _get_config(self) -> Config:
         return config
 
     def _validate_as_of_date(self, as_of: str) -> datetime:
-        """Validate date the as_of dates used to instantiate CladeTime."""
+        """Validate an as_of date (UTC) used to instantiate CladeTime."""
         if as_of is None:
             as_of_date = datetime.now()
         elif isinstance(as_of, datetime):
@@ -136,7 +177,4 @@ def _validate_as_of_date(self, as_of: str) -> datetime:
         if as_of_date < self._config.nextstrain_min_seq_date:
             raise CladeTimeInvalidDateError(f"Date must be after May 1, 2023: {as_of_date}")
 
-        if as_of_date > datetime.now().replace(tzinfo=timezone.utc):
-            raise CladeTimeInvalidDateError(f"Date cannot be in the future: {as_of_date}")
-
         return as_of_date

src/cladetime/exceptions.py

@@ -11,3 +11,7 @@ class CladeTimeInvalidDateError(Error):
 
 class CladeTimeInvalidURLError(Error):
     """Raised when CladeTime encounters an invalid URL."""
+
+
+class CladeTimeFutureDateWarning(Warning):
+    """Raised when CladeTime as_of date is in the future."""

tests/unit/test_cladetime.py

@@ -5,7 +5,7 @@
 import dateutil.tz
 import pytest
 from cladetime.cladetime import CladeTime
-from cladetime.exceptions import CladeTimeInvalidDateError, CladeTimeInvalidURLError
+from cladetime.exceptions import CladeTimeFutureDateWarning, CladeTimeInvalidDateError, CladeTimeInvalidURLError
 from freezegun import freeze_time
 
 
@@ -36,14 +36,32 @@ def test_cladetime_no_args():
             datetime(2024, 9, 30, 18, 24, 59, 655398),
             None,
             datetime(2024, 9, 30, 18, 24, 59, tzinfo=timezone.utc),
-            datetime(2025, 7, 13, 16, 21, 34, tzinfo=timezone.utc),
+            datetime(2024, 9, 30, 18, 24, 59, tzinfo=timezone.utc),
         ),
         (
             datetime(2024, 2, 22, 22, 22, 22, 222222, tzinfo=dateutil.tz.gettz("US/Eastern")),
             datetime(2024, 2, 22, tzinfo=dateutil.tz.gettz("US/Eastern")),
             datetime(2024, 2, 22, 22, 22, 22, tzinfo=timezone.utc),
             datetime(2024, 2, 22, tzinfo=timezone.utc),
         ),
+        (
+            "2023-12-21",
+            None,
+            datetime(2023, 12, 21, tzinfo=timezone.utc),
+            datetime(2023, 12, 21, tzinfo=timezone.utc),
+        ),
+        (
+            "2063-12-21",
+            None,
+            datetime(2025, 7, 13, 16, 21, 34, tzinfo=timezone.utc),
+            datetime(2025, 7, 13, 16, 21, 34, tzinfo=timezone.utc),
+        ),
+        (
+            "2063-12-21",
+            "2074-07-13",
+            datetime(2025, 7, 13, 16, 21, 34, tzinfo=timezone.utc),
+            datetime(2025, 7, 13, 16, 21, 34, tzinfo=timezone.utc),
+        ),
     ],
 )
 def test_cladetime_as_of_dates(sequence_as_of, tree_as_of, expected_sequence_as_of, expected_tree_as_of):
@@ -54,12 +72,21 @@ def test_cladetime_as_of_dates(sequence_as_of, tree_as_of, expected_sequence_as_
     assert ct.tree_as_of == expected_tree_as_of
 
 
-@pytest.mark.parametrize("bad_date", ["2020-07-13", "2022-12-32", "2063-04-05"])
+@pytest.mark.parametrize("bad_date", ["2020-07-13", "2022-12-32"])
 def test_cladetime_invalid_date(bad_date):
     with pytest.raises(CladeTimeInvalidDateError):
         CladeTime(sequence_as_of=bad_date, tree_as_of=bad_date)
 
 
+def test_cladetime_future_date():
+    with pytest.warns(CladeTimeFutureDateWarning):
+        CladeTime(sequence_as_of="2063-07-13")
+    with pytest.warns(CladeTimeFutureDateWarning):
+        CladeTime(tree_as_of="2063-07-13")
+    with pytest.warns(CladeTimeFutureDateWarning):
+        CladeTime(sequence_as_of="2023-12-31", tree_as_of="2063-07-13")
+
+
 @pytest.mark.parametrize(
     "sequence_as_of, expected_content",
     [