Warnings about VariationPath overrides when none are used

[alexander-held]

The

variation override specified, but {VariationPath} not found in default path

warning message triggers for histogram inputs even when no overrides are used at the moment.

Example test that will currently fail for test__histo_path:

# no variation path anywhere, so no warning
assert (
    collector._histo_path(
        "f.root:h1", "", {}, {}, {}, None
    )
    == "f.root:h1"
)
assert (
    "variation override specified, but {VariationPath} not found in default path"
    not in [rec.message for rec in caplog.records]
)
caplog.clear()

This needs to be fixed, presumably in templates.collector._histo_path.

[MoAly98]

@alexander-held I think the existing test on this is also not probing the correct bit of the code...

Consider this test for example:

    # warning: no variation path in template
    assert (
        collector._histo_path(
            "f.root:h1", "", {},  {"VariationPath": "sample.root"}, {},, None
        )
        == "f.root:h1"
    )
    assert (
        "variation override specified, but {VariationPath} not found in default path"
        in [rec.message for rec in caplog.records]

• The variation path is passed in the sample dictionary, so it should be the next argument
• We test for overrides on variation path when a systematic is defined only, and in this test, the systematic is not defined (no template specified). Is there a valid setup where the template key in the systematic dictionary does not exist and VariationPath is non-empty? if not, maybe this is a logic that needs to be added in collector._histo_path.

The following is a valid setup for a systematic:

{"Name": "variation", "Up": {"SamplePath": "var", "VariationPath": "up"}}

whereas

{"VariationPath": "sample.root"}

is not.