feat(nano): use decorator to export a Blueprint

[jansegre]

Motivation

The current method of assigning to __blueprint__ has some drawbacks. This proposal uses a decorator which should already be familiar because of @view and @public decorators.

Acceptance Criteria

• Move hathor.nanocontracts.on_chain_blueprints.BLUEPRINT_CLASS_NAME to hathor.nanocontracts.types.BLUEPRINT_EXPORT_NAME
• Introduce hathor.nanocontracts.export which just sets __blueprint__ at the module where it is called, which means it is backwards compatible:

  @export
  class Foo(Blueprint):
      pass

  Has the same runtime effect of:

  class Foo(Blueprint):
      pass
  __blueprint__ = Foo

Checklist

• If you are requesting a merge into master, confirm this code is production-ready and can be included in future releases as soon as it gets merged

[github-actions]

Bencher Report

Branch	feat/nano/blueprint-export-decorator
Testbed	ubuntu-22.04

Click to view all benchmark results

Benchmark	Latency	Benchmark Result minutes (m) (Result Δ%)	Lower Boundary minutes (m) (Limit %)	Upper Boundary minutes (m) (Limit %)
sync-v2 (up to 20000 blocks)	📈 view plot 🚷 view threshold	1.84 m (+9.18%) Baseline: 1.68 m	1.51 m (82.43%)	2.02 m (90.98%)

🐰 View full continuous benchmarking report in Bencher

[codecov]

Codecov Report

❌ Patch coverage is 81.63265% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.86%. Comparing base (9d0e7dd) to head (eb235f2).
⚠️ Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
hathor/verification/on_chain_blueprint_verifier.py	78.78%	5 Missing and 2 partials ⚠️
hathor/nanocontracts/types.py	83.33%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1395      +/-   ##
==========================================
- Coverage   85.87%   85.86%   -0.02%     
==========================================
  Files         431      431              
  Lines       32700    32733      +33     
  Branches     5096     5102       +6     
==========================================
+ Hits        28082    28105      +23     
- Misses       3598     3608      +10     
  Partials     1020     1020              

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[glevco]

Using global or globals() doesn't work?

[jansegre]

It doesn't work because it would refer to the hathor.nanocontracts.types's globals, not the module that uses @export's globals.