[lldb] Make several attempts to read the PID in TestAppleSimulatorOSType

[JDevlieghere]

Summary

The current code fails when the the first attempt to read the PID from stderr doesn't match the given regex. This patch changes the code to make up to 10 attempts.

[aprantl]

lldb/test/API/tools/lldb-server/TestAppleSimulatorOSType.py

66

I'm not sure I would call this RETRIES since we're just reading more lines from stderr. May MAX_LINES?

[JDevlieghere]

Forgot the link in the commit message. Landed in 7adf5bd18147b8acdab6e2720b4073e8c35bdf9a

lldb/test/API/tools/lldb-server/TestAppleSimulatorOSType.py

 
 
 import gdbremote_testcase
 import lldbgdbserverutils
 from lldbsuite.test.decorators import *
 from lldbsuite.test.lldbtest import *
 from lldbsuite.test import lldbutil
 
 import json
 
 class TestAppleSimulatorOSType(gdbremote_testcase.GdbRemoteTestCaseBase):
 
     mydir = TestBase.compute_mydir(__file__)
 
+    # Number of attempts to read the PID from the simctl output.
+    PID_RETRIES = 10
+
     def check_simulator_ostype(self, sdk, platform, arch='x86_64'):
-        sim_devices_str = subprocess.check_output(['xcrun', 'simctl', 'list',
-                                                   '-j', 'devices']).decode("utf-8")
+        cmd = ['xcrun', 'simctl', 'list', '-j', 'devices']
+        self.trace(' '.join(cmd))
+        sim_devices_str = subprocess.check_output(cmd).decode("utf-8")
         sim_devices = json.loads(sim_devices_str)['devices']
         # Find an available simulator for the requested platform
         deviceUDID = None
         deviceRuntime = None
         for simulator in sim_devices:
             if isinstance(simulator,dict):
                 runtime = simulator['name']
                 devices = simulator['devices']
def check_simulator_ostype(self, sdk, platform, arch='x86_64'):
         # Launch the process using simctl
         self.assertIsNotNone(deviceUDID)
         exe_name = 'test_simulator_platform_{}'.format(platform)
         sdkroot = subprocess.check_output(['xcrun', '--show-sdk-path', '--sdk',
                                            sdk]).decode("utf-8")
         self.build(dictionary={ 'EXE': exe_name, 'SDKROOT': sdkroot.strip(),
                                 'ARCH': arch })
         exe_path = self.getBuildArtifact(exe_name)
-        sim_launcher = subprocess.Popen(['xcrun', 'simctl', 'spawn', '-s',
-                                         deviceUDID, exe_path,
-                                         'print-pid', 'sleep:10'],
-                                        stderr=subprocess.PIPE)
+        cmd = [
+            'xcrun', 'simctl', 'spawn', '-s', deviceUDID, exe_path,
+            'print-pid', 'sleep:10'
+        ]
+        self.trace(' '.join(cmd))
+        sim_launcher = subprocess.Popen(cmd, stderr=subprocess.PIPE)
         # Get the PID from the process output
         pid = None
-        while not pid:
+
+        # Make PID_RETRIES attempt to get the PID.
+        for _ in range(0, self.PID_RETRIES):
             stderr = sim_launcher.stderr.readline().decode("utf-8")
-            if stderr == '':
+            if not stderr:
                 continue
-            m = re.match(r"PID: (.*)", stderr)
-            self.assertIsNotNone(m)
-            pid = int(m.group(1))
+            match = re.match(r"PID: (.*)", stderr)
+            if match:
+                pid = int(match.group(1))
+                break
+
+        # Make sure we found the PID.
+        self.assertIsNotNone(pid)
 
         # Launch debug monitor attaching to the simulated process
         self.init_debugserver_test()
         server = self.connect_to_debug_monitor(attach_pid=pid)
 
         # Setup packet sequences
         self.add_no_ack_remote_stream()
         self.add_process_info_collection_packets()