Restore original pidproxy arg parsing behavior. References Supervisor#1418

Issue Supervisor#1418 reported that pidproxy did not parse arguments correctly.
A fix was suggested that was committed in ab26970.

After actually running pidproxy to verify that fix, I found that pidproxy
no longer worked.  The original code in pidproxy was correct.

This change partially reverts ab26970,
restoring the original pidproxy behavior but leaving the unit tests.  Two
new end-to-end tests for pidproxy were added: one to verify a command
without any arguments, and one with.

Author: mnaberez

CHANGES.rst

@@ -1,9 +1,6 @@
 4.3.0.dev0 (Next Release)
 -------------------------
 
-- Fixed a bug where ``pidproxy`` would not pass arguments to the command
-  it runs.
-
 4.2.2 (2021-02-26)
 ------------------
 

supervisor/pidproxy.py

@@ -19,17 +19,16 @@ class PidProxy:
 
     def __init__(self, args):
         try:
-            self.pidfile = args[1]
-            command_and_cmdargs = args[2:]
-            self.command = os.path.abspath(command_and_cmdargs[0])
-            self.cmdargs = command_and_cmdargs[1:]
+            self.pidfile, cmdargs = args[1], args[2:]
+            self.abscmd = os.path.abspath(cmdargs[0])
+            self.cmdargs = cmdargs
         except (ValueError, IndexError):
             self.usage()
             sys.exit(1)
 
     def go(self):
         self.setsignals()
-        self.pid = os.spawnv(os.P_NOWAIT, self.command, self.cmdargs)
+        self.pid = os.spawnv(os.P_NOWAIT, self.abscmd, self.cmdargs)
         while 1:
             time.sleep(5)
             try:

supervisor/tests/test_end_to_end.py

@@ -279,6 +279,20 @@ def test_issue_1298(self):
         self.addCleanup(bash.kill, signal.SIGINT)
         bash.expect('spewage 2', timeout=30)
 
+    def test_issue_1481_pidproxy_cmd_with_no_args(self):
+        args = ['-m', 'supervisor.pidproxy', 'nonexistent-pidfile', "/bin/echo"]
+        pidproxy = pexpect.spawn(sys.executable, args, encoding='utf-8')
+        self.addCleanup(pidproxy.kill, signal.SIGINT)
+        pidproxy.expect(pexpect.EOF)
+        self.assertEqual(pidproxy.before.strip(), "")
+
+    def test_issue_1481_pidproxy_cmd_with_args(self):
+        args = ['-m', 'supervisor.pidproxy', 'nonexistent-pidfile', "/bin/echo", "1", "2"]
+        pidproxy = pexpect.spawn(sys.executable, args, encoding='utf-8')
+        self.addCleanup(pidproxy.kill, signal.SIGINT)
+        pidproxy.expect(pexpect.EOF)
+        self.assertEqual(pidproxy.before.strip(), "1 2")
+
 def test_suite():
     return unittest.findTestCases(sys.modules[__name__])
 

supervisor/tests/test_pidproxy.py

@@ -13,5 +13,5 @@ def test_ctor_parses_args(self):
         args = ["pidproxy.py", "/path/to/pidfile", "./cmd", "-arg1", "-arg2"]
         pp = self._makeOne(args)
         self.assertEqual(pp.pidfile, "/path/to/pidfile")
-        self.assertEqual(pp.command, os.path.abspath("./cmd"))
-        self.assertEqual(pp.cmdargs, ["-arg1", "-arg2"])
+        self.assertEqual(pp.abscmd, os.path.abspath("./cmd"))
+        self.assertEqual(pp.cmdargs, ["./cmd", "-arg1", "-arg2"])