Shellscript throws errors but somehow is still working - shell

Question

I have this shellscrip to deploy code from travis on another machine.
#!/bin/sh
codecov
function sshDeploy {
printf -v __ %q "$1"
ssh -oStrictHostKeyChecking=no deployuser#178.62.252.23 "cd api; git pull origin master; git checkout $__;./sbt clean; ./sbt stage; ./neeedo restart; exit $?"
}
sshDeploy $TRAVIS_COMMIT
exit $?
This script runs without any errors on my macbook. However when I run it on travis(unfortunately I can't tell you which unix they run on their buildagents because I dont have direct access to them) I observe strange behaviour.
Errors are thrown but the script is somehow still being executed.
./after-success.sh: 3: ./after-success.sh: function: not found
./after-success.sh: 4: printf: Illegal option -v
Warning: Permanently added '178.62.252.23' (ECDSA) to the list of known hosts.
From https://github.com/HTW-Projekt-2014-Commercetools/api
* branch master -> FETCH_HEAD
... Git Log ...
Stopping Neeedo-API: ..done.
Starting Neeedo-API: ....done.
./after-success.sh: 6: ./after-success.sh: Syntax error: "}" unexpected
Now I have 2 problems/question:
Why are these errors thrown and how can I make this shellscript as plattform independent as possible? I dont know which buildagent is running my script so it should run on the common unix systems.
How can I make sure that the script returns an errorcode different than 0 if something fails to make sure that the travis build fails. At the moment its still returning a green build and also the app is started somehow as you can see in the logs...
(3.) Is there a way to format the commands that are sent through ssh in a better way than in a long string?

Answer 1

Change it to a bash script.
First line: #!/bin/bash.
sh
$ printf -v ___ %q "$1"
sh: 1: printf: Illegal option -v
bash
$ printf -v ___ %q "$1"
<no error>

Answer 2

The errors are thrown because the function keyword and the -v argument to printf aren't being understood by /bin/sh on the remote host.
Changing the shebang line to #!/bin/bash will fix those errors.
The reason the script still "works" even with the above errors (quotes because it isn't really working I don't think) is because you got lucky. /bin/sh didn't understand the function keyword so it ignored that line entirely which then meant that it likely ran the ssh command directly (not through the function call) and didn't use $__ correctly (because of the printf -v error) so didn't run the correct git checkout command.
I would have expected to see an error about not knowing what the sshDeploy command was but maybe it didn't do that or maybe it got hidden by something else.
That all being said there's no real reason for that function at all.
The exit status from a script is the exit status of the last command that ran so there's no need to end with exit $?.
With that and without the function your script just becomes.
codecov
printf -v __ %q "$TRAVIS_COMMIT"
ssh -oStrictHostKeyChecking=no deployuser#178.62.252.23 "cd api; git pull origin master; git checkout $__;./sbt clean; ./sbt stage; ./neeedo restart"
And you can even avoid the printf -v most likely since git refs are unlikely (if not incapable) of containing any shell metacharacters that would need escaping when expanded in a shell string like that (I believe at least). Though this is certainly safer if you don't mind the bash requirement.