bpo-5001: More-informative multiprocessing error messages (#3079)
* Make error message more informative
Replace assertions in error-reporting code with more-informative version that doesn't cause confusion over where and what the error is.
* Additional clarification + get travis to check
* Change from SystemError to TypeError
As suggested in PR comment by @pitrou, changing from SystemError; TypeError appears appropriate.
* NEWS file installation; ACKS addition (will do my best to justify it by additional work)
* Making current AssertionErrors in multiprocessing more informative
* Blurb added re multiprocessing managers.py, queues.py cleanup
* Further multiprocessing cleanup - went through pool.py
* Fix two asserts in multiprocessing/util.py
* Most asserts in multiprocessing more informative
* Didn't save right version
* Further work on multiprocessing error messages
* Correct typo
* Correct typo v2
* Blasted colon... serves me right for trying to work on two things at once
* Simplify NEWS entry
* Update 2017-08-18-17-16-38.bpo-5001.gwnthq.rst
* Update 2017-08-18-17-16-38.bpo-5001.gwnthq.rst
OK, never mind.
* Corrected (thanks to pitrou) error messages for notify
* Remove extraneous backslash in docstring.
diff --git a/Lib/multiprocessing/reduction.py b/Lib/multiprocessing/reduction.py
index 7f65947..deca19c 100644
--- a/Lib/multiprocessing/reduction.py
+++ b/Lib/multiprocessing/reduction.py
@@ -165,7 +165,10 @@
if len(cmsg_data) % a.itemsize != 0:
raise ValueError
a.frombytes(cmsg_data)
- assert len(a) % 256 == msg[0]
+ if len(a) % 256 != msg[0]:
+ raise AssertionError(
+ "Len is {0:n} but msg[0] is {1!r}".format(
+ len(a), msg[0]))
return list(a)
except (ValueError, IndexError):
pass