test: expect that files may disappear from /proc/PID/fd/ #31614

1. 
   vasild commented at 10:45 am on January 7, 2025: contributor

   get_socket_inodes() calls os.listdir() and then iterates on the results using os.readlink(). However a file may disappear from the directory after os.listdir() and before os.readlink() resulting in a FileNotFoundError exception.

   It is expected that this may happen for bitcoind which is running and could open or close files or sockets at any time. Thus ignore the FileNotFoundError exception.

2. test: expect that files may disappear from /proc/PID/fd/

   `get_socket_inodes()` calls `os.listdir()` and then iterates on the
   results using `os.readlink()`. However a file may disappear from the
   directory after `os.listdir()` and before `os.readlink()` resulting in a
   `FileNotFoundError` exception.
   
   It is expected that this may happen for `bitcoind` which is running and
   could open or close files or sockets at any time. Thus ignore the
   `FileNotFoundError` exception.

   b2e9fdc00f
3. 
   DrahtBot commented at 10:45 am on January 7, 2025: contributor

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/31614.

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   Type	Reviewers
   ACK	theuni
   Concept ACK	luke-jr

   If your review is incorrectly listed, please react with 👎 to this comment and the bot will ignore it on the next update.

4. DrahtBot added the label Tests on Jan 7, 2025
5. 
   vasild commented at 10:47 am on January 7, 2025: contributor

   A failure like this observed in #31349 in CI job https://github.com/bitcoin/bitcoin/actions/runs/12633511389/job/35241370470?pr=31349:

    02025-01-07T09:20:07.629000Z TestFramework (INFO): Bind test for ['[::1]']
    12025-01-07T09:20:08.155000Z TestFramework (ERROR): Unexpected exception caught during testing
    2Traceback (most recent call last):
    3  File "/home/runner/work/_temp/test/functional/test_framework/test_framework.py", line 135, in main
    4    self.run_test()
    5  File "/home/runner/work/_temp/ci/scratch/build-x86_64-pc-linux-gnu/test/functional/rpc_bind.py", line 99, in run_test
    6    self._run_loopback_tests()
    7  File "/home/runner/work/_temp/ci/scratch/build-x86_64-pc-linux-gnu/test/functional/rpc_bind.py", line 126, in _run_loopback_tests
    8    self.run_bind_test(['[::1]'], '[::1]', ['[::1]'],
    9  File "/home/runner/work/_temp/ci/scratch/build-x86_64-pc-linux-gnu/test/functional/rpc_bind.py", line 45, in run_bind_test
   10    assert_equal(set(get_bind_addrs(pid)), set(expected))
   11                     ^^^^^^^^^^^^^^^^^^^
   12  File "/home/runner/work/_temp/test/functional/test_framework/netutil.py", line 84, in get_bind_addrs
   13    inodes = get_socket_inodes(pid)
   14             ^^^^^^^^^^^^^^^^^^^^^^
   15  File "/home/runner/work/_temp/test/functional/test_framework/netutil.py", line 40, in get_socket_inodes
   16    target = os.readlink(os.path.join(base, item))
   17             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   18FileNotFoundError: [Errno 2] No such file or directory: '/proc/18148/fd/19'
   

6. luke-jr approved
7. 
   luke-jr commented at 4:20 am on January 8, 2025: member

   crACK
8. theuni approved
9. 
   theuni commented at 4:40 pm on January 8, 2025: member

   utACK b2e9fdc00f5c40c241a37739f7b73b74c2181e39

   I looked around for a way to iterate on a cached list using os.scandir, but one doesn’t seems to exist. So this makes sense to me.

10. DrahtBot requested review from luke-jr on Jan 8, 2025

Contributors
vasild DrahtBot luke-jr theuni

Review Requested
luke-jr

Labels
Tests