pythongh-134954: Hard-cap max file descriptors in subprocess test fd_status (pythonGH-134955)

itamaro · miss-islington · commit a476a4634227 · 2025-05-31T14:29:10.000Z
* Hard-cap max file descriptors in subprocess test fd_status On some systems, `SC_OPEN_MAX` may return a very large value (i.e. 10**30), leading to the subprocess test timing out (or run forever). Prevent this situation by applying a hard cap on how many file descriptors are checked. * Fix typo in usage docstring s/fd_stats/fd_status/ (cherry picked from commit f58873e) Co-authored-by: Itamar Oren <itamarost@gmail.com>
diff --git a/Lib/test/subprocessdata/fd_status.py b/Lib/test/subprocessdata/fd_status.py
@@ -2,7 +2,7 @@
 file descriptors on stdout.
 
 Usage:
-fd_stats.py: check all file descriptors
+fd_status.py: check all file descriptors (up to 255)
 fd_status.py fd1 fd2 ...: check only specified file descriptors
 """
 
@@ -18,7 +18,7 @@
             _MAXFD = os.sysconf("SC_OPEN_MAX")
         except:
             _MAXFD = 256
-        test_fds = range(0, _MAXFD)
+        test_fds = range(0, min(_MAXFD, 256))
     else:
         test_fds = map(int, sys.argv[1:])
     for fd in test_fds:
