MAINT: Remove import except block

[j-t-1]

pypdf is now using version 43.0.3 of cryptography, so the fallback for previous versions can be removed.
https://cryptography.io/en/latest/changelog/#v43-0-0

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 95.63%. Comparing base (27edc06) to head (1002136).

Files with missing lines	Patch %	Lines
pypdf/_crypt_providers/_cryptography.py	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2957      +/-   ##
==========================================
- Coverage   96.36%   95.63%   -0.74%     
==========================================
  Files          52       52              
  Lines        8751     8753       +2     
  Branches     1593     1593              
==========================================
- Hits         8433     8371      -62     
- Misses        190      252      +62     
- Partials      128      130       +2     

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[stefan6419846]

I disagree with this. Although cryptography is newer in our code, we still support the old variant as far as I know.

[stefan6419846]

If ever, we should do this in a proper deprecation process.

[j-t-1]

The change was only added four months ago. Reverting this (closing this commit) would be for users who do update pypdf but do not update cryptography. Could defer to @MartinThoma who added the importing flexibility.

[stefan6419846]

Martin added this as our tests were failing when we tried to publish a release. IMHO there is nothing which Martin could add here. If we require a minimum version of some dependency, we should communicate this properly.

[stefan6419846]

The user has no control over these directly, thus this does not make much sense here.

[j-t-1]

Remove deprecate_with_replacement and replace with the following message?

print("The Cryptography library moved the location of ARC4 in v43.0.0. pypdf 6.0.0 will require Cryptography v43.0.0.")

[stefan6419846]

print is not intended for user-facing messages. Apart from this, I still do not really see the benefit of dropping the old versions if its only an import and no functionality ...

[j-t-1]

Their CHANGELOG.rst says:

ARC4 will be removed from the cipher module in 48.0.0.

They are on version 44.0.0 now, and released 42.0.0 and 43.0.0 this year. Eventually we may have to have a requirement for version 47.0.0 or less.

Having a simpler imports requirement by then may be useful: in the future there may be three situations that we will have to handle.

[stefan6419846]

This removal seems to only affect the old variant - the new primary import will not be removed and thus pypdf should not break here.

[j-t-1]

Reading their documentation, I think you are right. I would prefer we deprecate_with_replacement, in time the number of users who update pypdf and not cryptography will become small. However, since it currently works and they did the namespace move fairly recently, there is reason to keep the same, so feel free to close this.