Propagate exceptions in AndStatus and Signal.set to the user

ophyd/signal.py

@@ -225,7 +225,7 @@ def trigger(self):
         # NOTE: this is a no-op that exists here for bluesky purposes
         #       it may need to be moved in the future
         d = Status(self)
-        d._finished()
+        d.set_finished()
         return d
 
     def wait_for_connection(self, timeout=0.0):
@@ -394,10 +394,12 @@ def set(self, value, *, timeout=None, settle_time=None, **kwargs):
         )
 
         def set_thread():
+            _exception = None
+
             try:
                 self._set_and_wait(value, timeout, **kwargs)
-            except TimeoutError:
-                success = False
+            except TimeoutError as e:
+                _exception = e
                 self.log.warning(
                     "%s: _set_and_wait(value=%s, timeout=%s, atol=%s, rtol=%s, kwargs=%s)",
                     self.name,
@@ -407,8 +409,8 @@ def set_thread():
                     self.rtolerance,
                     kwargs,
                 )
-            except Exception:
-                success = False
+            except Exception as e:
+                _exception = e
                 self.log.exception(
                     "%s: _set_and_wait(value=%s, timeout=%s, atol=%s, rtol=%s, kwargs=%s)",
                     self.name,
@@ -419,7 +421,6 @@ def set_thread():
                     kwargs,
                 )
             else:
-                success = True
                 self.log.debug(
                     "%s: _set_and_wait(value=%s, timeout=%s, atol=%s, rtol=%s, kwargs=%s) succeeded => %s",
                     self.name,
@@ -439,7 +440,12 @@ def set_thread():
                 th = self._set_thread
                 # these two must be in this order to avoid a race condition
                 self._set_thread = None
-                st._finished(success=success)
+
+                if _exception is not None:
+                    st.set_exception(_exception)
+                else:
+                    st.set_finished()
+
                 del th
 
         if self._set_thread is not None:
@@ -2247,7 +2253,7 @@ def set(self, value, *, timeout=DEFAULT_WRITE_TIMEOUT, settle_time=None):
         st = Status(self, timeout=timeout, settle_time=settle_time)
 
         def put_callback(**kwargs):
-            st._finished(success=True)
+            st.set_finished()
 
         self.put(value, use_complete=True, callback=put_callback)
         return st

ophyd/status.py

@@ -2,7 +2,6 @@
 import threading
 import time
 from collections import deque
-from functools import partial
 from logging import LoggerAdapter
 from warnings import warn
 
@@ -593,13 +592,13 @@ def inner(status):
                         # At least one is done.
                         # If it failed, do not wait for the second one.
                         if (not l_success) and l_done:
-                            self._finished(success=False)
+                            self.set_exception(self.left.exception())
                         elif (not r_success) and r_done:
-                            self._finished(success=False)
+                            self.set_exception(self.right.exception())
 
                         elif l_success and r_success and l_done and r_done:
                             # Both are done, successfully.
-                            self._finished(success=True)
+                            self.set_finished()
                         # Else one is done, successfully, and we wait for #2,
                         # when this function will be called again.
 
@@ -793,7 +792,7 @@ def check_value(self, *args, **kwargs):
 
         # If successfull indicate completion
         if success:
-            self._finished(success=True)
+            self.set_finished()
 
     def set_finished(self):
         """
@@ -863,9 +862,7 @@ def __init__(
                 f"Stability time ({stability_time}) must be less than full status timeout ({timeout})"
             )
         self._stability_time = stability_time
-        self._stable_timer = threading.Timer(
-            self._stability_time, partial(self._finished, success=True)
-        )
+        self._stable_timer = threading.Timer(self._stability_time, self.set_finished)
 
         # Start timeout thread in the background
         super().__init__(
@@ -891,7 +888,7 @@ def check_value(self, *args, **kwargs):
             else:
                 self._stable_timer.cancel()
                 self._stable_timer = threading.Timer(
-                    self._stability_time, partial(self._finished, success=True)
+                    self._stability_time, self.set_finished
                 )
 
         # Do not fail silently