Add missing __repr__ to streams.EmptyStreamReader

[elonen]

EmptyStreamReader currently inherits __repr__ from StreamReader , which then tries to access non-existing fields, causing AttributeErrors. The bug causes issues like this in upstream code: https://github.com/miguelgrinberg/python-socketio/issues/1032

This PR adds a custom __repr__ to EmptyStreamReader to fix the problem.

[codecov[bot]]

Codecov Report

Merging #6916 (ae9e897) into master (52fa599) will increase coverage by 0.00%. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #6916   +/-   ##
=======================================
  Coverage   97.41%   97.41%           
=======================================
  Files         106      106           
  Lines       30879    30882    +3     
  Branches     3843     3843           
=======================================
+ Hits        30081    30084    +3     
  Misses        600      600           
  Partials      198      198           

Flag	Coverage Δ
CI-GHA	97.32% <100.00%> (+<0.01%)	:arrow_up:
OS-Linux	96.97% <100.00%> (-0.01%)	:arrow_down:
OS-Windows	95.42% <100.00%> (+<0.01%)	:arrow_up:
OS-macOS	96.59% <100.00%> (-0.01%)	:arrow_down:
Py-3.10.6	96.71% <100.00%> (-0.42%)	:arrow_down:
Py-3.10.7	96.85% <100.00%> (+1.61%)	:arrow_up:
Py-3.11.0-rc.2	96.49% <100.00%> (-0.05%)	:arrow_down:
Py-3.7.13	96.80% <100.00%> (+<0.01%)	:arrow_up:
Py-3.7.9	95.31% <100.00%> (+<0.01%)	:arrow_up:
Py-3.8.10	95.21% <100.00%> (+<0.01%)	:arrow_up:
Py-3.8.13	96.75% <100.00%> (+<0.01%)	:arrow_up:
Py-3.9.13	97.04% <100.00%> (-0.03%)	:arrow_down:
Py-3.9.14	96.47% <100.00%> (?)
Py-pypy7.3.9	96.34% <100.00%> (-0.01%)	:arrow_down:
VM-macos	96.59% <100.00%> (-0.01%)	:arrow_down:
VM-ubuntu	96.97% <100.00%> (-0.01%)	:arrow_down:
VM-windows	95.42% <100.00%> (+<0.01%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
aiohttp/streams.py	97.46% <100.00%> (+0.01%)	:arrow_up:
tests/test_streams.py	100.00% <100.00%> (ø)

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[patchback[bot]]

Backport to 3.9: 💚 backport PR created

✅ Backport PR branch: patchback/backports/3.9/abafcdac6cbef06bc555cb77b1ebe724d2a098ec/pr-6916

Backported as https://github.com/aio-libs/aiohttp/pull/7106

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