Enhance pickle compatibility: support legacy tuple state and maintain…

[polybassa]

… packet metadata during serialization

The new regression tests protect against breaking older pickle payloads by ensuring legacy tuple-state unpickling still works. They also lock in current behavior for the new state format by checking full metadata and comments fidelity after pickle roundtrip. This gives coverage for both backward compatibility and current serialization behavior in one place: test/regression.uts.

Checklist :

• If you are new to Scapy: I have checked CONTRIBUTING.md (esp. section submitting-pull-requests)
• I squashed commits belonging together
• I added unit tests or explained why they are not relevant
• I executed the regression tests (using tox)
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• This PR uses (partially) AI-generated code. If so:
  • I ensured the generated code follows the internal concepts of scapy
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  • If this PR contains more than 500 lines of code (excluding unit tests) I considered splitting this PR.
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fixes #xxx

[codecov]

Codecov Report

❌ Patch coverage is 88.57143% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.26%. Comparing base (1745d39) to head (2bece55).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
scapy/packet.py	88.57%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4982      +/-   ##
==========================================
- Coverage   80.27%   80.26%   -0.01%     
==========================================
  Files         382      382              
  Lines       94349    94362      +13     
==========================================
+ Hits        75736    75739       +3     
- Misses      18613    18623      +10     

Files with missing lines	Coverage Δ
scapy/packet.py	84.70% <88.57%> (-0.14%)	⬇️

... and 5 files with indirect coverage changes

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• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[polybassa]

@guedou I've encountered a problem that "old" pickled values can not be unpickled anymore. I've added support for the legacy pickle structure.

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[guedou]

Looks good to me, but I don't understand why we need to have backwards compatibility for this feature.

[polybassa]

I stumbled over it when un-pickling older objects. I would help me for some use cases, if we stay backward compatible.

[guedou]

I really don’t feel that we should keep both serialization methods.Sent from my iPhoneOn 27 Apr 2026, at 19:29, Nils Weiss ***@***.***> wrote:polybassa left a comment (secdev/scapy#4982) I stumbled over it when un-pickling older objects. I would help me for some use cases, if we stay backward compatible. —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you were mentioned.Message ID: ***@***.***>

[polybassa]

This PR just added the old deserialisation. For serialisation we only use the new format. At least for one release, I recommend to still support the old deserialisation.