apport-unpack: fix reading from stdin

[bdrung]

Reading a report from stdin fails:

Traceback (most recent call last):
  File "bin/apport-unpack", line 91, in <module>
    main()
  File "bin/apport-unpack", line 70, in main
    report.load(report_file, binary=False)
  File "problem_report.py", line 155, in load
    self._assert_bin_mode(file)
  File "problem_report.py", line 792, in _assert_bin_mode
    assert not hasattr(file, "encoding"), "file stream must be in binary mode"
AssertionError: file stream must be in binary mode

This failure has been found by mypy after adding type hints to ProblemReport.load.

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (7c9c1cd) 83.80% compared to head (648d445) 83.84%.

Files	Patch %	Lines
bin/apport-unpack	95.23%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #255      +/-   ##
==========================================
+ Coverage   83.80%   83.84%   +0.03%     
==========================================
  Files          93       93              
  Lines       18837    18851      +14     
==========================================
+ Hits        15787    15805      +18     
+ Misses       3050     3046       -4     

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[schopin-pro]

LGTM, but I'm really confused, what's the original bug exactly? It lookt to me that the previous code was always giving in sys.stdin, which is a TextIOWrapper so not binary.

[bdrung]

That the crash with apport 2.27.0:

$ echo "foo" | apport-unpack - /tmp/foo
Traceback (most recent call last):
  File "/usr/bin/apport-unpack", line 92, in <module>
    main()
  File "/usr/bin/apport-unpack", line 68, in main
    report = load_report(args.report)
             ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/bin/apport-unpack", line 41, in load_report
    report.load(sys.stdin, binary=False)
  File "/usr/lib/python3/dist-packages/problem_report.py", line 151, in load
    self._assert_bin_mode(file)
  File "/usr/lib/python3/dist-packages/problem_report.py", line 769, in _assert_bin_mode
    assert not hasattr(file, "encoding"), "file stream must be in binary mode"
AssertionError: file stream must be in binary mode

[schopin-pro]

LGTM, there's a wider issue but it's out of scope.