changeset 45825:8f07f5a9c3de

worker: raise exception instead of calling sys.exit() with child's code When a worker process returns an error code, we would call `sys.exit()` with that exit code on the main process. The `SystemExit` exception would then get caught in `scmutil.callcatch()`, which would return that error code. The comment there says "Commands shouldn't sys.exit directly", which I agree with. This patch changes it so we raise a specific exception when a worker fails so we can catch instead. I think that means that `SystemExit` is now always an internal error. (I had earlier thought that this call to `sys.exit()` was from within the child process until Matt Harbison made me look again, so thanks for that!) Differential Revision: https://phab.mercurial-scm.org/D9287
author Martin von Zweigbergk <martinvonz@google.com>
date Sat, 07 Nov 2020 21:50:28 -0800
parents 9ac96b9fa76e
children 21733e8c924f
files mercurial/error.py mercurial/scmutil.py mercurial/worker.py tests/test-worker.t
diffstat 4 files changed, 14 insertions(+), 3 deletions(-) [+]
line wrap: on
line diff
--- a/mercurial/error.py	Tue Nov 03 09:56:02 2020 -0800
+++ b/mercurial/error.py	Sat Nov 07 21:50:28 2020 -0800
@@ -130,6 +130,13 @@
     __bytes__ = _tobytes
 
 
+class WorkerError(Exception):
+    """Exception raised when a worker process dies."""
+
+    def __init__(self, status_code):
+        self.status_code = status_code
+
+
 class InterventionRequired(Hint, Exception):
     """Exception raised when a command requires human intervention."""
 
--- a/mercurial/scmutil.py	Tue Nov 03 09:56:02 2020 -0800
+++ b/mercurial/scmutil.py	Sat Nov 07 21:50:28 2020 -0800
@@ -219,6 +219,9 @@
         ui.error(_(b"abort: %s\n") % inst.message)
         if inst.hint:
             ui.error(_(b"(%s)\n") % inst.hint)
+    except error.WorkerError as inst:
+        # Don't print a message -- the worker already should have
+        return inst.status_code
     except ImportError as inst:
         ui.error(_(b"abort: %s!\n") % stringutil.forcebytestr(inst))
         m = stringutil.forcebytestr(inst).split()[-1]
--- a/mercurial/worker.py	Tue Nov 03 09:56:02 2020 -0800
+++ b/mercurial/worker.py	Sat Nov 07 21:50:28 2020 -0800
@@ -300,7 +300,7 @@
     if status:
         if status < 0:
             os.kill(os.getpid(), -status)
-        sys.exit(status)
+        raise error.WorkerError(status)
     if hasretval:
         yield True, retval
 
--- a/tests/test-worker.t	Tue Nov 03 09:56:02 2020 -0800
+++ b/tests/test-worker.t	Sat Nov 07 21:50:28 2020 -0800
@@ -85,11 +85,12 @@
   [255]
 
   $ hg --config "extensions.t=$abspath" --config 'worker.numcpus=8' \
-  > test 100000.0 abort --traceback 2>&1 | egrep '(SystemExit|Abort)'
+  > test 100000.0 abort --traceback 2>&1 | egrep '(WorkerError|Abort)'
       raise error.Abort(b'known exception')
   mercurial.error.Abort: known exception (py3 !)
   Abort: known exception (no-py3 !)
-  SystemExit: 255
+      raise error.WorkerError(status)
+  mercurial.error.WorkerError: 255
 
 Traceback must be printed for unknown exceptions