internal: change datetime implementation

Rework our implementation of tarantool.Datetime class. Previously it had
relied on pandas.Timestamp and pandas.Timedelta. There were user
complaints about pandas as a requirement since it's rather heavy. Now
our implementation of datetime uses built-in datetime.datetime and
datetime.timedelta, as well as dateutil.relativedelta.relativedelta and
some other built-in tools.

It is expected that the implementation change wouldn't affect users, but
some minor behavior traits were broken in this patch:
- Now we rely on datetime argument validation which if differs from
  pandas one. For example, it doesn't allow overflows for fields.
  Exceptions that user may receive from internal datetime are, of
  course, had changed as well.
- We drop the support of `__eq__` for pandas.Timestamp. We simply
  compared underlying pandas.Timestamp with argument one, and now it's
  impossible. It the feature would be useful later, we may implement its
  comparison in some compatible way.
- __repr__ has been changed since internal representation has been
  changed as well.

python-dateutil is a relatively small (ver. 2.8.2 wheel size on pip is
247 kB, while msgpack 1.0.5 wheel is 316 kB and pytz 2023.3 wheel is
502 kB; numpy 1.24.2 wheel is 17.3 MB and pandas 2.0.0 wheel is
12.3 MB) and a popular library to work with various datetime cases.
Since working with datetime is always bothersome, I think it's
preferable to rely on well-tested library rather than implement months
addition from the scratch.

Closes #290

Author: DifferentialOrange

CHANGELOG.md

@@ -11,6 +11,17 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Migrate to built-in `Warning` instead of a custom one.
 - Migrate to built-in `RecursionError` instead of a custom one.
 - Collect full exception traceback.
+- Rework `tarantool.Datetime` implementation to use built-in
+  `datetime.datetime`. External changes are as follows. Some of them
+  are **breaking**.
+  - Package no longer depends on `pandas`, only on `python-dateutil`
+    (previously it was installed as a dependency of `pandas`) (#290).
+  - `__repr__` has been changed.
+  - Class is no longer expected to throw `pandas.Timestamp`
+    exceptions. `datetime.datetime` exceptions and custom exceptions will
+    be thrown instead of them.
+  - Input arguments are validated with `datetime.datetime` rules.
+  - Drop the support of `__eq__` operator for `pandas.Timestamp`.
 
 ## 0.12.1 - 2023-02-28
 

docs/source/conf.py

@@ -344,7 +344,6 @@
 intersphinx_mapping = {
     'python': ('http://docs.python.org/', None),
     'msgpack': ('https://msgpack-python.readthedocs.io/en/latest/', None),
-    'pandas': ('https://pandas.pydata.org/docs/', None),
     'pytz': ('https://pytz.sourceforge.net/', None),
 }
 

requirements.txt

@@ -1,4 +1,4 @@
 msgpack
-pandas
+python-dateutil
 pytz
 dataclasses; python_version <= '3.6'

rpm/SPECS/python-tarantool.spec

@@ -29,7 +29,7 @@ Python client library for Tarantool.}
 %package -n python3-%{srcname}
 
 Requires:       python3-msgpack
-Requires:       python3-pandas
+Requires:       python3-dateutil
 Requires:       python3-pytz
 
 Summary:        %{summary}