gh-91880: add try/except around `signal.signal` (#91881)

Fixes gh-91880.

1 files changed, 7 insertions, 1 deletions

diff --git a/Lib/asyncio/runners.py b/Lib/asyncio/runners.py
index 2bb9ca331f..d274576b10 100644
--- a/Lib/asyncio/runners.py
+++ b/Lib/asyncio/runners.py
@@ -100,7 +100,13 @@ class Runner:
             and signal.getsignal(signal.SIGINT) is signal.default_int_handler
         ):
             sigint_handler = functools.partial(self._on_sigint, main_task=task)
-            signal.signal(signal.SIGINT, sigint_handler)
+            try:
+                signal.signal(signal.SIGINT, sigint_handler)
+            except ValueError:
+                # `signal.signal` may throw if `threading.main_thread` does
+                # not support signals (e.g. embedded interpreter with signals
+                # not registered - see gh-91880)
+                signal_handler = None
         else:
             sigint_handler = None