How to exit bash function if error?

Question

I am making a presubmit script. It looks like this:

function presubmit() {
  gradle test android
  gradle test ios
  gradle test server
  git push origin master
}

I want the function to exit, if any of the tests fail so it won't push a bug to git. How?

Answer 1

1. Use subshell ( .. ) with set -e; to make it more concise, you can do this:

build() {( set -e        # Fail early
  build_cmd_step_1
  build_cmd_step_2
  build_cmd_step_3
  ...
)}

Then, the function will fail on the first failure and you can intercept the exit status:

build
exit_status=$?
if [ ${exit_status} -ne 0 ]; then
  echo "We have error - build failed!"
  exit "${exit_status}"
fi

2. Alternatively, the && \ chaining inside a function is also good (https://stackoverflow.com/a/51913013/1375784), though it might get bad if you have a bigger function.

Both methods can be good, depending on your use case (in some cases using subshells may cause some unwanted side effects)

Answer 2

The way I do it is to add && \ after every command in the function (except the last one).

function presubmit() {
    gradle test android && \
    gradle test ios && \
    gradle test server && \
    git push origin master
}

Answer 3

I would make script more granulated:

#!/bin/bash

function test() {
  gradle test android
  gradle test ios
  gradle test server
}
function push() {
  git push origin master
}
# this subshell runs similar to try/catch
(
  # this flag will make to exit from current subshell on any error inside test or push
  set -e
  test
  push
)
# you catch errors with this if
if [ $? -ne 0 ]; then
  echo "We have error"
  exit $?
fi

We track error only inside test and push. You can add more actions outside of subshell where test and push run. You can also this way add different scope for errors (let consider it as try/catch)