Fixed issue where signal timer not resetting properly (#946)

Author: sternj

.github/workflows/test-smoketests.yml

@@ -51,6 +51,12 @@ jobs:
     - name: decorator smoke test
       run: python test/smoketest_profile_decorator.py
 
+      # NOTE: this is a regression test for signals not being
+      # restarted properly. It checks whether the program 
+      # halts or runs forever, not for correctness of timing.
+    - name: signal smoketest
+      run: python test/smoketest.py test/signal_test.py
+      timeout-minutes: 0.5
     # FIXME: these tests are broken under the current Github runner
     #
     # - name: line invalidation test

scalene/scalene_profiler.py

@@ -731,7 +731,6 @@ def cpu_signal_handler(
                         to_wait = min(remaining_time, next_interval)
                     else:
                         to_wait = next_interval
-                        Scalene.client_timer.reset()
                     Scalene.__signal_manager.restart_timer(to_wait)
                 else:
                     Scalene.__signal_manager.restart_timer(next_interval)

test/signal_test.py

@@ -0,0 +1,16 @@
+import signal
+
+iterations = 10
+
+def my_handler(sig, frame):
+    global iterations
+    print(f"seconds remaining: {iterations}")
+    if iterations > 0:
+        iterations -= 1
+        signal.setitimer(signal.ITIMER_REAL, 1.0, 0)
+    
+signal.signal(signal.SIGALRM, my_handler)
+signal.setitimer(signal.ITIMER_REAL, 1.0, 0)
+
+while iterations:
+    signal.pause()