MAINT: Deduplicate CatalogAttributes and CatalogDictionary

[j-t-1]

Currently these classes represent the same thing. To simplify,
CatalogDictionary is deprecated with replacement CatalogAttributes.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.85%. Comparing base (75e339c) to head (7d9dc5b).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3868      +/-   ##
==========================================
- Coverage   97.85%   97.85%   -0.01%     
==========================================
  Files          57       57              
  Lines       10702    10701       -1     
  Branches     2001     2001              
==========================================
- Hits        10472    10471       -1     
  Misses        127      127              
  Partials      103      103              

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[j-t-1]

Closes #3866.

[stefan6419846]

Why did you decide to use the name of the functionally less complex class?

[j-t-1]

Why did you decide to use the name of the functionally less complex class?

In constants.py, CatalogDictionary is the only one ending in Dictionary in this variable:

PDF_KEYS = (
    AnnotationDictionaryAttributes,
    CatalogAttributes,
    CatalogDictionary,
    CcittFaxDecodeParameters,
    CheckboxRadioButtonAttributes,
    ColorSpaces,
    Core,
    DocumentInformationAttributes,
    EncryptionDictAttributes,
    FieldDictionaryAttributes,
    FileSpecificationDictionaryEntries,
    FilterTypeAbbreviations,
    FilterTypes,
    GoToActionArguments,
    GraphicsStateParameters,
    ImageAttributes,
    InteractiveFormDictEntries,
    LzwFilterParameters,
    PageAttributes,
    PageLayouts,
    PagesAttributes,
    Resources,
    StreamAttributes,
    TrailerKeys,
    TypArguments,
    TypFitArguments,
)

So went with that. Later noticed that CA is more readable than CD (although may be subjective).

[stefan6419846]

I hope nobody will be instantiating the constants classes. CatalogDictionary.NAMES will not trigger the deprecation at the moment and thus this needs further fixing.

[j-t-1]

I will do this, but unsure how.

[stefan6419846]

We previously did this for single keys by implementing corresponding class properties, but this is most likely not feasible with this amount of keys.

I guess we could overwrite __getattr__ to issue warnings accordingly.

[j-t-1]

@stefan6419846 with the deprecation CatalogDictionary does not exist, so cannot be added to:

CatalogDictionary = __create_old_class_instance

def _external_getattr(self, name):
    deprecate_with_replacement("CatalogDictionary", "CatalogAttributes", "7.0.0")
    return getattr(CatalogAttributes, name)

CatalogDictionary .__getattr__ = _external_getattr

What am I misunerstanding?

[stefan6419846]

You have to keep it a class and overwrite all relevant attributes.

[j-t-1]

class CatalogDictionary:
    """§7.7.2 of the 1.7 and 2.0 references."""
    def __init__(self) -> None:
        deprecate_with_replacement("CatalogDictionary", "CatalogAttributes", "7.0.0")

    def __getattribute__(self, item: str) -> str:
        deprecate_with_replacement("CatalogDictionary", "CatalogAttributes", "7.0.0")
        return getattr(CatalogAttributes, item)

with pytest.warns(
        DeprecationWarning,
        match=r"^CatalogDictionary is deprecated and will be removed in pypdf 7\.0\.0\. "
              r"Use CatalogAttributes instead\.$",
):
    CatalogDictionary.TYPE

FAILED tests/test_constants.py::test_catalog_dictionary - Failed: DID NOT WARN. No warnings of type (<class 'DeprecationWarning'>,) were emitted.

What is the flaw in the class that is not giving a warning in the test?

__getattr__ and __getattribute__ gives the same error, and I will change back to __getattr__.

[stefan6419846]

__getattr__ might only trigger on class instances, not on direct attribute access. It seems this either needs a ton of classproperty definitions or some more magic.