Assertion `memcached_failed(rc)' failed

[christopheg]

Hi,

We might be hitting a bug here when using PHP to connect tot Memcached:

Nov 21 15:41:47 job0.myapplication.net application_service[2627697]: account_import (15242218): ./src/libmemcached/storage.cc:257: memcached_return_t memcached_send_ascii(Memcached*, memcached_instance_st*, const char*, size_t, const char*, size_t, time_t, uint32_t, uint64_t, bool, bool, memcached_storage_action_t): Assertion `memcached_failed(rc)' failed.
Dec 02 18:12:05 job0.myapplication.net application_service[1667523]: account_import (15860032): ./src/libmemcached/storage.cc:257: memcached_return_t memcached_send_ascii(Memcached*, memcached_instance_st*, const char*, size_t, const char*, size_t, time_t, uint32_t, uint64_t, bool, bool, memcached_storage_action_t): Assertion `memcached_failed(rc)' failed.
Dec 03 11:37:50 job0.myapplication.net application_service[1885508]: order_execute (15912452): ./src/libmemcached/storage.cc:257: memcached_return_t memcached_send_ascii(Memcached*, memcached_instance_st*, const char*, size_t, const char*, size_t, time_t, uint32_t, uint64_t, bool, bool, memcached_storage_action_t): Assertion `memcached_failed(rc)' failed.
Dec 03 13:14:59 job0.myapplication.net application_service[1924822]: order_execute (15944444): ./src/libmemcached/storage.cc:257: memcached_return_t memcached_send_ascii(Memcached*, memcached_instance_st*, const char*, size_t, const char*, size_t, time_t, uint32_t, uint64_t, bool, bool, memcached_storage_action_t): Assertion `memcached_failed(rc)' failed.
Dec 03 14:44:02 job0.myapplication.net application_service[1958669]: order_execute (15971006): ./src/libmemcached/storage.cc:257: memcached_return_t memcached_send_ascii(Memcached*, memcached_instance_st*, const char*, size_t, const char*, size_t, time_t, uint32_t, uint64_t, bool, bool, memcached_storage_action_t): Assertion `memcached_failed(rc)' failed.
Dec 03 18:12:40 job0.myapplication.net application_service[2037836]: order_execute (16030452): ./src/libmemcached/storage.cc:257: memcached_return_t memcached_send_ascii(Memcached*, memcached_instance_st*, const char*, size_t, const char*, size_t, time_t, uint32_t, uint64_t, bool, bool, memcached_storage_action_t): Assertion `memcached_failed(rc)' failed.

When looking in the code, this seems to be the line we are triggering:
https://github.com/awesomized/libmemcached/blame/v1.x/src/libmemcached/storage.cc#L257
which calls
https://github.com/awesomized/libmemcached/blob/v1.x/include/libmemcached-1.0/return.h#L24

Can somebody explain me the purpose of this? I don't understand why the library should do an 'assert' here.
It seems this line has been here for 14 years. Before this commit, this function would return 'rc':
https://github.com/awesomized/libmemcached/blame/v1.x/src/libmemcached/storage.cc#L257
For my understanding, this stops the code execution in rc is not within one define constants.

A similar issue was already opened before (#49) but I fail to understand how the proposed commit solved this issue.

Another user posted a similar problem: https://stackoverflow.com/questions/16067307/weird-memcached-issue-with-apache
One of the proposed solutions was to switch to binary protocol.

pylibmc seems to have an issue which looks similar: lericson/pylibmc#218
Also here, they think libmemcached should not trigger an abort.

Would it be able for someone to have a look at it?

Kind regards,
Christophe