Pandas 1.3.5 Shallow Copy Discrepancy

[michaelmckinsey1]

Problem

When running the unit test test_copy:test_copy() on GitHub for python3.7 and pandas==1.3.5 the following error will occur

        # Shallow copy of data
        node = other.dataframe.index.get_level_values("node")[0]
        profile = other.dataframe.index.get_level_values("profile")[0]
        other.dataframe.loc[(node, profile), "nid"] = -1
>       assert (
            other.dataframe.loc[(node, profile), "nid"]
            == self.dataframe.loc[(node, profile), "nid"]
        )
E       assert -1.0 == 26.0

This error does not happen when running locally, tested with python3.7.2 and pandas==1.3.5.

Current Fix

Our current fix was to change the pandas version on GitHub to pandas==1.2.5 and the error does not occur. For reference the error does not occur for pandas==1.4 and pandas==2.0, so our suspicion is the error only occurs for pandas==1.3.5.

This is somewhat known by pandas and they fixed the inconsistency in pandas==1.5. See:

• BUG: pandas-1.4.0 .loc "shallow" copies do not update pandas-dev/pandas#45743
• DEPR: df.iloc[:, foo] = bar attempt to set inplace pandas-dev/pandas#45333

[michaelmckinsey1]

Resolved by depreciating Python 3.7 (#107)