bug: data type inference in timestamp .delta expression

[martin-wiebusch-thg]

What happened?

I am trying to compute the difference between a timestamp literal and a timestamp column using the .delta method. The following code

import ibis
from ibis import _
import datetime as dt

con = ibis.bigquery.connect()
end_date = dt.datetime(2024, 6, 13, tzinfo=dt.timezone.utc)

table = (
    con.table('some_bigquery_table')
    .select(ts=_.some_timestamp_column)
    .mutate(dt=ibis.literal(end_date).delta(_.ts, 'second'))
)
print(con.compile(transactions))

raises InputTypeError: Unable to infer datatype of value _.ts with type <class 'ibis.common.deferred.Deferred'>

It works if I first create the literal as a column and then mutate it:

import ibis
from ibis import _
import datetime as dt

con = ibis.bigquery.connect()
end_date = dt.datetime(2024, 6, 13, tzinfo=dt.timezone.utc)

table = (
    con.table('some_bigquery_table')
    .select(
        ts=_.Order_Created,
        dt=ibis.literal(end_date),
    )
    .mutate(dt=_.dt.delta(_.ts, 'second'))
)
print(con.compile(transactions))

What version of ibis are you using?

9.0.0

What backend(s) are you using, if any?

BigQuery

Relevant log output

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
File ~/.pyenv/versions/3.10.6/envs/general/lib/python3.10/site-packages/ibis/expr/operations/core.py:69, in Value.__coerce__(cls, value, T, S)
     68 try:
---> 69     dtype = dt.DataType.from_typehint(T)
     70 except TypeError:

File ~/.pyenv/versions/3.10.6/envs/general/lib/python3.10/site-packages/ibis/expr/datatypes/core.py:173, in DataType.from_typehint(cls, typ, nullable)
    172 if issubclass(typ, Parametric):
--> 173     raise TypeError(
    174         f"Cannot construct a parametric {typ.__name__} datatype based "
    175         "on the type itself"
    176     )
    177 elif issubclass(typ, DataType):

TypeError: Cannot construct a parametric Timestamp datatype based on the type itself

During handling of the above exception, another exception occurred:

InputTypeError                            Traceback (most recent call last)
Cell In[15], line 17
      3     transactions = (
      4         con.table('the-hut-group.ditto_hqdw.Transactions')
      5         .select(ts=_.Order_Created)
   (...)
     11         # .mutate(dt=_.dt.delta(_.ts, 'second'))
     12     )
     13     print(con.compile(transactions))
---> 17 extract_events(con, con2)

Cell In[15], line 6, in extract_events(con, con2)
      1 def extract_events(con, con2):
      2     end_date = dt.datetime(2024, 6, 13, tzinfo=dt.timezone.utc)
      3     transactions = (
      4         con.table('the-hut-group.ditto_hqdw.Transactions')
      5         .select(ts=_.Order_Created)
----> 6         .mutate(dt=ibis.literal(end_date).delta(_.ts, 'second'))
      7         # .select(
      8         #     ts=_.Order_Created,
      9         #     dt=ibis.literal(end_date),
     10         # )
     11         # .mutate(dt=_.dt.delta(_.ts, 'second'))
     12     )
     13     print(con.compile(transactions))

File ~/.pyenv/versions/3.10.6/envs/general/lib/python3.10/site-packages/ibis/expr/types/temporal.py:800, in TimestampValue.delta(self, other, part)
    729 def delta(
    730     self,
    731     other: datetime.datetime | Value[dt.Timestamp],
   (...)
    745     | Value[dt.String],
    746 ) -> ir.IntegerValue:
    747     """Compute the number of `part`s between two timestamps.
    748 
    749     ::: {.callout-note}
   (...)
    798     └──────────────┘
    799     """
--> 800     return ops.TimestampDelta(left=self, right=other, part=part).to_expr()

File ~/.pyenv/versions/3.10.6/envs/general/lib/python3.10/site-packages/ibis/common/bases.py:72, in AbstractMeta.__call__(cls, *args, **kwargs)
     52 def __call__(cls, *args, **kwargs):
     53     """Create a new instance of the class.
     54 
     55     The subclass may override the `__create__` classmethod to change the
   (...)
     70 
     71     """
---> 72     return cls.__create__(*args, **kwargs)

File ~/.pyenv/versions/3.10.6/envs/general/lib/python3.10/site-packages/ibis/common/grounds.py:119, in Annotable.__create__(cls, *args, **kwargs)
    116 @classmethod
    117 def __create__(cls, *args: Any, **kwargs: Any) -> Self:
    118     # construct the instance by passing only validated keyword arguments
--> 119     kwargs = cls.__signature__.validate(cls, args, kwargs)
    120     return super().__create__(**kwargs)

File ~/.pyenv/versions/3.10.6/envs/general/lib/python3.10/site-packages/ibis/common/annotations.py:490, in Signature.validate(self, func, args, kwargs)
    487 param = self.parameters[name]
    488 pattern = param.annotation.pattern
--> 490 result = pattern.match(value, this)
    491 if result is NoMatch:
    492     errors.append((name, value, pattern))

File ~/.pyenv/versions/3.10.6/envs/general/lib/python3.10/site-packages/ibis/common/patterns.py:865, in GenericCoercedTo.match(self, value, context)
    863 def match(self, value, context):
    864     try:
--> 865         value = self.origin.__coerce__(value, **self.params)
    866     except CoercionError:
    867         return NoMatch

File ~/.pyenv/versions/3.10.6/envs/general/lib/python3.10/site-packages/ibis/expr/operations/core.py:71, in Value.__coerce__(cls, value, T, S)
     69         dtype = dt.DataType.from_typehint(T)
     70     except TypeError:
---> 71         dtype = dt.infer(value)
     73 try:
     74     return Literal(value, dtype=dtype)

File ~/.pyenv/versions/3.10.6/envs/general/lib/python3.10/site-packages/ibis/common/dispatch.py:140, in lazy_singledispatch.<locals>.call(arg, *args, **kwargs)
    137 @functools.wraps(func)
    138 def call(arg, *args, **kwargs):
    139     impl = dispatcher.dispatch(type(arg))
--> 140     return impl(arg, *args, **kwargs)

File ~/.pyenv/versions/3.10.6/envs/general/lib/python3.10/site-packages/ibis/expr/datatypes/value.py:35, in infer(value)
     32 @lazy_singledispatch
     33 def infer(value: Any) -> dt.DataType:
     34     """Infer the corresponding ibis dtype for a python object."""
---> 35     raise InputTypeError(
     36         f"Unable to infer datatype of value {value!r} with type {type(value)}"
     37     )

InputTypeError: Unable to infer datatype of value _.ts with type <class 'ibis.common.deferred.Deferred'>

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