# Receiving badarg converting list to reference on GitHub workflow and EUnit test **URL:** \ **Category:** Questions / Help\ **Tags:** eunit, github\ **Created:** [May 21, 2023, 12:16am UTC](https://erlangforums.com/t/receiving-badarg-converting-list-to-reference-on-github-workflow-and-eunit-test/2619 "2023-05-21T00:16:35Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![williamthome](https://erlangforums.com/user_avatar/erlangforums.com/williamthome/32/471_2.png) [@williamthome](https://erlangforums.com/u/williamthome)\ **Post date:** [May 21, 2023, 12:16am UTC](https://erlangforums.com/t/receiving-badarg-converting-list-to-reference-on-github-workflow-and-eunit-test/2619/1 "2023-05-21T00:16:35Z")
Hey all. I have a falling eunit test on GitHub, but locally all tests are ok. The GitHub action log: ```erlang Run rebar3 do eunit, ct ===> Verifying dependencies... ===> Analyzing applications... ===> Compiling changeset ===> Performing EUnit tests... .............F.. Failures: 1) changeset_reference_validator:validate_change_test/0: module 'changeset_reference_validator' Failure/Error: {error,badarg, [{erlang,list_to_ref, ["#Ref<0.4192537678.4073193475.71181>"], [{error_info,#{module => erl_erts_errors}}]}, {changeset_reference_validator,validate_change_test, 0, [{file, "/__w/changeset/changeset/src/validators/changeset_reference_validator.erl"}, {line,35}]}, {eunit_test,'-mf_wrapper/2-fun-0-',2, [{file,"eunit_test.erl"},{line,273}]}, {eunit_test,run_testfun,1, [{file,"eunit_test.erl"},{line,71}]}, {eunit_proc,run_test,1, [{file,"eunit_proc.erl"},{line,531}]}, {eunit_proc,with_timeout,3, [{file,"eunit_proc.erl"},{line,356}]}, {eunit_proc,handle_test,2, [{file,"eunit_proc.erl"},{line,514}]}, {eunit_proc,tests_inorder,3, [{file,"eunit_proc.erl"},{line,456}]}]} Output: Finished in 0.178 seconds 16 tests, 1 failures ===> Error running tests Error: Process completed with exit code 1. ``` This is falling ```erlang list_to_ref("#Ref<0.4192537678.4073193475.71181>"). ``` but why? This is my machine log: ```erlang rebar3 do eunit, ct ===> Verifying dependencies... ===> Analyzing applications... ===> Compiling changeset ===> Performing EUnit tests... ................ Finished in 0.113 seconds 16 tests, 0 failures ===> Verifying dependencies... ===> Analyzing applications... ===> Compiling changeset ===> Running Common Test suites... All 0 tests passed. ``` GitHub workflow and my machine are using the same `25.3.2` OTP version. The lib repo: [GitHub - williamthome/changeset: An OTP library to validate data based on Ecto changeset library (Elixir).](https://github.com/williamthome/changeset) I appreciate any help. ---
**Author:** ![fancycade](https://erlangforums.com/user_avatar/erlangforums.com/fancycade/32/1187_2.png) [@fancycade](https://erlangforums.com/u/fancycade)\ **Post date:** [May 21, 2023, 1:42am UTC](https://erlangforums.com/t/receiving-badarg-converting-list-to-reference-on-github-workflow-and-eunit-test/2619/2 "2023-05-21T01:42:39Z")
Not much help but I reproduced your CI issue locally on my local machine (FreeBSD). ~~Maybe a missing dependency?~~ eunit failed, but everything else worked. ---
**Author:** ![fancycade](https://erlangforums.com/user_avatar/erlangforums.com/fancycade/32/1187_2.png) [@fancycade](https://erlangforums.com/u/fancycade)\ **Post date:** [May 21, 2023, 2:09am UTC](https://erlangforums.com/t/receiving-badarg-converting-list-to-reference-on-github-workflow-and-eunit-test/2619/3 "2023-05-21T02:09:13Z")
Submitted a PR: [Fix list\_to\_ref string in unit test by fancycade · Pull Request #1 · williamthome/changeset · GitHub](https://github.com/williamthome/changeset/pull/1) Passing build: [build #993137 - success](https://builds.sr.ht/~fancycade/job/993137) ---
**Author:** ![williamthome](https://erlangforums.com/user_avatar/erlangforums.com/williamthome/32/471_2.png) [@williamthome](https://erlangforums.com/u/williamthome)\ **Post date:** [May 21, 2023, 7:24am UTC](https://erlangforums.com/t/receiving-badarg-converting-list-to-reference-on-github-workflow-and-eunit-test/2619/4 "2023-05-21T07:24:51Z")
Thanks, @fancycade! `make_ref()` makes much more sense here. BTW, I got the reference value from the `list_to_ref` example in [Erlang docs](https://www.erlang.org/doc/man/erlang.html#list_to_ref-1): ```erlang > list_to_ref("#Ref<0.4192537678.4073193475.71181>"). #Ref<0.4192537678.4073193475.71181> ``` Sounds strange to me why this happened. Any idea? ---
**Author:** ![williamthome](https://erlangforums.com/user_avatar/erlangforums.com/williamthome/32/471_2.png) [@williamthome](https://erlangforums.com/u/williamthome)\ **Post date:** [May 21, 2023, 9:30am UTC](https://erlangforums.com/t/receiving-badarg-converting-list-to-reference-on-github-workflow-and-eunit-test/2619/5 "2023-05-21T09:30:35Z")
Oh, there is a big warning in the docs: ```erlang This BIF is intended for debugging and is not to be used in application programs. ``` I will be considering this as the answer to my previous question. ---
**Author:** ![fancycade](https://erlangforums.com/user_avatar/erlangforums.com/fancycade/32/1187_2.png) [@fancycade](https://erlangforums.com/u/fancycade)\ **Post date:** [May 21, 2023, 4:44pm UTC](https://erlangforums.com/t/receiving-badarg-converting-list-to-reference-on-github-workflow-and-eunit-test/2619/6 "2023-05-21T16:44:45Z")
I noticed that warning as well, but doesn’t explain why the Erlang docs ref doesn’t work. ```erlang list_to_ref(ref_to_list(make_ref())) ``` As long as you use a different ref it works. My guess was a breaking change with ref formats since the docs were published, but maybe there is a difference deeper down the stack. What OS are you running? ---
**Author:** ![williamthome](https://erlangforums.com/user_avatar/erlangforums.com/williamthome/32/471_2.png) [@williamthome](https://erlangforums.com/u/williamthome)\ **Post date:** [May 21, 2023, 5:34pm UTC](https://erlangforums.com/t/receiving-badarg-converting-list-to-reference-on-github-workflow-and-eunit-test/2619/7 "2023-05-21T17:34:46Z")
> [@fancycade](#): > > What OS are you running? ```erlang cat /etc/lsb-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=22.04 DISTRIB_CODENAME=jammy DISTRIB_DESCRIPTION="Ubuntu 22.04.2 LTS" ``` ---
**Author:** ![fancycade](https://erlangforums.com/user_avatar/erlangforums.com/fancycade/32/1187_2.png) [@fancycade](https://erlangforums.com/u/fancycade)\ **Post date:** [May 21, 2023, 9:16pm UTC](https://erlangforums.com/t/receiving-badarg-converting-list-to-reference-on-github-workflow-and-eunit-test/2619/8 "2023-05-21T21:16:56Z")
Hmmm i wouldnt expect that to cause issues. Maybe someone more experienced can solve the mystery. ---
**Author:** ![gorillainduction](https://erlangforums.com/user_avatar/erlangforums.com/gorillainduction/32/1966_2.png) [@gorillainduction](https://erlangforums.com/u/gorillainduction)\ **Post date:** [May 23, 2023, 1:51pm UTC](https://erlangforums.com/t/receiving-badarg-converting-list-to-reference-on-github-workflow-and-eunit-test/2619/9 "2023-05-23T13:51:32Z")
> [@williamthome](#): > > ```erlang > This BIF is intended for debugging and is not to be used in application programs. > > ``` > > I will be considering this as the answer to my previous question. \ Yes, this is correct. Use this is for debugging and for logs exclusively. \ This is from memory, so it might not be totally correct, but rather an educated guess. As I recall it, the first number in the reference is the node id (e.g., 0 for the local node), and then there is a scheduler id embedded in the reference so that you don’t have to aquire a lock when creating a reference in a scheduler. There are other things going on as well, but I think this is the culprit. So, if you create a reference on a node with a lot of schedulers and you take the textual representation of the ref to another node with fewer schedulers, you might have created a ref that refers to a higher scheduler id than is avaliable on that node, but the 0 at the start tells the node that this should be treated as a ref that was created at the local node. When sending refs that are not textual inbetween nodes, there will be a new node number in the ref on the remote node, and it will work anyway. So, If I would hazard a guess, you were running the test on a decent development machine with a bunch of cores (and therefore a bunch of schedulers), and the ci system is running on fewer cores and hence fewer schedulers. As an experiment and as anecdotal proof 😉 ```erlang 1> list_to_ref("#Ref<0.4192537678.4073193475.71181>"). #Ref<0.4192537678.4073193475.71181> 2> erlang:system_info(schedulers). 3 ``` and ```erlang 1> list_to_ref("#Ref<0.4192537678.4073193475.71181>"). ** exception error: bad argument in function list_to_ref/1 called as list_to_ref("#Ref<0.4192537678.4073193475.71181>") *** argument 1: not a textual representation of a reference 2> erlang:system_info(schedulers). 2 ``` ---
**Author:** ![williamthome](https://erlangforums.com/user_avatar/erlangforums.com/williamthome/32/471_2.png) [@williamthome](https://erlangforums.com/u/williamthome)\ **Post date:** [May 24, 2023, 12:24am UTC](https://erlangforums.com/t/receiving-badarg-converting-list-to-reference-on-github-workflow-and-eunit-test/2619/10 "2023-05-24T00:24:14Z")
Interesting! I believe this is correct and will accept it as the solution. Glad to hear an experienced Erlanger. Thanks for the informative post, @gorillainduction!