[Lldb-commits] [lldb] [lldb/test] Retry the remote platform connection in dotest (PR #215425)

[Med Ismail Bennani via lldb-commits]

https://github.com/medismailben created https://github.com/llvm/llvm-project/pull/215425

Connecting to a remote platform through port forwarding can fail transiently even when the device and the tunnel are healthy, which aborts the entire test suite run before a single test executes.

Retry the `ConnectRemote` call a few times with a short backoff before giving up. Each failed attempt is still printed with its attempt number, and a device that is genuinely unreachable fails with the same error on every attempt and then exits as before, so this does not mask a broken connection, it only adds a few seconds in that case.

>From 84573c65cc8a2e08e3e7a6442df78a1db71f7d49 Mon Sep 17 00:00:00 2001
From: Med Ismail Bennani <ismail at bennani.ma>
Date: Mon, 10 Aug 2026 15:43:22 -0700
Subject: [PATCH] [lldb/test] Retry the remote platform connection in dotest

Connecting to a remote platform through port forwarding can fail
transiently even when the device and the tunnel are healthy, which aborts
the entire test suite run before a single test executes.

Retry the ConnectRemote call a few times with a short backoff before giving up.
Each failed attempt is still printed with its attempt number, and a device that
is genuinely unreachable fails with the same error on every attempt and then
exits as before, so this does not mask a broken connection: it only costs a few
seconds in that case.

Signed-off-by: Med Ismail Bennani <ismail at bennani.ma>
---
 lldb/packages/Python/lldbsuite/test/dotest.py | 28 +++++++++++++++----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/lldb/packages/Python/lldbsuite/test/dotest.py b/lldb/packages/Python/lldbsuite/test/dotest.py
index 2bd1d085f6ceb..680b2ab3da06f 100644
--- a/lldb/packages/Python/lldbsuite/test/dotest.py
+++ b/lldb/packages/Python/lldbsuite/test/dotest.py
@@ -31,6 +31,7 @@
 import subprocess
 import sys
 import tempfile
+import time
 
 # Third-party modules
 import unittest
@@ -1135,14 +1136,31 @@ def run_suite():
             platform_connect_options = lldb.SBPlatformConnectOptions(
                 configuration.lldb_platform_url
             )
-            err = lldb.remote_platform.ConnectRemote(platform_connect_options)
+            # Connecting to a remote platform through a port forward can fail
+            # transiently while the connection itself is perfectly healthy, so
+            # retry a few times before giving up. Every attempt is reported, and
+            # a device that is genuinely unreachable still fails quickly with the
+            # same error on each attempt, so this doesn't hide a broken device.
+            max_connect_attempts = 4
+            for attempt in range(1, max_connect_attempts + 1):
+                err = lldb.remote_platform.ConnectRemote(platform_connect_options)
+                if err.Success():
+                    break
+                print(
+                    "error: failed to connect to remote platform using URL "
+                    "'%s': %s (attempt %d of %d)"
+                    % (
+                        configuration.lldb_platform_url,
+                        err,
+                        attempt,
+                        max_connect_attempts,
+                    )
+                )
+                if attempt < max_connect_attempts:
+                    time.sleep(attempt)
             if err.Success():
                 print("Connected.")
             else:
-                print(
-                    "error: failed to connect to remote platform using URL '%s': %s"
-                    % (configuration.lldb_platform_url, err)
-                )
                 exitTestSuite(1)
         else:
             configuration.lldb_platform_url = None