process_iter(): use another global var to keep track of reused PIDs

psutil/__init__.py

@@ -85,6 +85,7 @@
 from ._common import NoSuchProcess
 from ._common import TimeoutExpired
 from ._common import ZombieProcess
+from ._common import debug
 from ._common import memoize_when_activated
 from ._common import wrap_numbers as _wrap_numbers
 from ._compat import PY3 as _PY3
@@ -613,8 +614,7 @@ def is_running(self):
             # time) and that is verified in __eq__.
             self._pid_reused = self != Process(self.pid)
             if self._pid_reused:
-                # remove this PID from `process_iter()` internal cache
-                _pmap.pop(self.pid, None)
+                _pids_reused.add(self.pid)
                 raise NoSuchProcess(self.pid)
             return True
         except ZombieProcess:
@@ -1464,6 +1464,7 @@ def pid_exists(pid):
 
 
 _pmap = {}
+_pids_reused = set()
 
 
 def process_iter(attrs=None, ad_value=None):
@@ -1501,6 +1502,10 @@ def remove(pid):
     gone_pids = b - a
     for pid in gone_pids:
         remove(pid)
+    while _pids_reused:
+        pid = _pids_reused.pop()
+        debug("refreshing Process instance for reused PID %s" % pid)
+        remove(pid)
     try:
         ls = sorted(list(pmap.items()) + list(dict.fromkeys(new_pids).items()))
         for pid, proc in ls:

psutil/tests/test_linux.py

@@ -1120,10 +1120,10 @@ def ifconfig(nic):
             except RuntimeError:
                 continue
             self.assertAlmostEqual(
-                stats.bytes_recv, ifconfig_ret['bytes_recv'], delta=1024 * 5
+                stats.bytes_recv, ifconfig_ret['bytes_recv'], delta=1024 * 10
             )
             self.assertAlmostEqual(
-                stats.bytes_sent, ifconfig_ret['bytes_sent'], delta=1024 * 5
+                stats.bytes_sent, ifconfig_ret['bytes_sent'], delta=1024 * 10
             )
             self.assertAlmostEqual(
                 stats.packets_recv, ifconfig_ret['packets_recv'], delta=1024

psutil/tests/test_misc.py

@@ -219,6 +219,7 @@ def test__all__(self):
         dir_psutil = dir(psutil)
         for name in dir_psutil:
             if name in (
+                'debug',
                 'long',
                 'tests',
                 'test',

psutil/tests/test_process.py

@@ -36,6 +36,7 @@
 from psutil._compat import PY3
 from psutil._compat import FileNotFoundError
 from psutil._compat import long
+from psutil._compat import redirect_stderr
 from psutil._compat import super
 from psutil.tests import APPVEYOR
 from psutil.tests import CI_TESTING
@@ -763,7 +764,6 @@ def test_long_cmdline(self):
             if ret == []:
                 # https://github.com/giampaolo/psutil/issues/2250
                 raise unittest.SkipTest("OPENBSD: returned EBUSY")
-            self.assertEqual(p.cmdline(), cmdline)
 
         self.assertEqual(p.cmdline(), cmdline)
 
@@ -1378,15 +1378,27 @@ def test_zombie_process_status_w_exc(self):
 
     def test_reused_pid(self):
         # Emulate a case where PID has been reused by another process.
+        if PY3:
+            from io import StringIO
+        else:
+            from StringIO import StringIO
+
         subp = self.spawn_testproc()
         p = psutil.Process(subp.pid)
         p._ident = (p.pid, p.create_time() + 100)
 
         list(psutil.process_iter())
         self.assertIn(p.pid, psutil._pmap)
         assert not p.is_running()
+
         # make sure is_running() removed PID from process_iter()
         # internal cache
+        with redirect_stderr(StringIO()) as f:
+            list(psutil.process_iter())
+        self.assertIn(
+            "refreshing Process instance for reused PID %s" % p.pid,
+            f.getvalue(),
+        )
         self.assertNotIn(p.pid, psutil._pmap)
 
         assert p != psutil.Process(subp.pid)