Bash: stop on error in sourced script

Question

In a shell script to be executed, I can abort on errors using set -e.

In a sourced script, however, using set -e will kill the original shell if a later command exits with an error status.

source set_e.sh
./exit_1.sh
# shell dies

A trivial solution would be to set +e at the end of the script, but this would break the parent's set -e if used (which may very well happen if someone wraps my script in the future).

How can I get abort-on-error functionality in a sourced script?

Answer 1

It's impossible. However you can opt to use a subshell if you want:

(
    set -e
    source another.sh
)

Only that environment of calling script can never be altered by the called script.

Note: It may be important to separate both commands with newline and not use a semicolon.

Answer 2

Well, the question is not very clear re: what the original author wanted after intercepting the error in the sourced script, however, as an entry point for the solution the following will suffice:

You can set a trap on ERR and handle the error inside the sourced script there. Below are two scenarios: one with the sourced script using "set -e" and another with the sourced script NOT using "set -e".

The primary script is calling the secondary script with defined "set -e" and catches an error:

[galaxy => ~]$ cat primary.sh
#!/bin/sh

set -e
echo 'Primary script'
trap 'echo "Got an error from the secondary script"' ERR
source secondary.sh
trap - ERR
echo 'Primary script exiting'
[galaxy => ~]$ cat secondary.sh
#!/bin/sh

echo 'Secondary script'
set -e
echo 'Secondary script generating an error'
false
echo 'Secondary script - should not be reached'
[galaxy => ~]$ ./primary.sh
Primary script
Secondary script
Secondary script generating an error
Got an error from the secondary script
[galaxy => ~]$

The primary script is calling the secondary script without "set -e" and catches an error:

[galaxy => ~]$ cat primary.sh
#!/bin/sh

set -e
echo 'Primary script'
trap 'echo "Got an error from the secondary script"' ERR
source secondary.sh
trap - ERR
echo 'Primary script exiting'
[galaxy => ~]$ cat secondary.sh
#!/bin/sh

echo 'Secondary script'
echo 'Secondary script generating an error'
false
echo 'Secondary script - should not be reached if sourced by primary.sh'
[galaxy => ~]$ ./primary.sh
Primary script
Secondary script
Secondary script generating an error
Got an error from the secondary script
[galaxy => ~]$

As a bonus: intercepting an error in the sourced script and continuing:

[galaxy => ~]$ cat primary.sh
#!/bin/sh

echo 'Primary script'
i=0
while [ $i = 0 ]; do
    i=1
    trap 'echo "Got an error from the secondary script"; break' ERR
    source secondary.sh
done
trap - ERR
echo 'Primary script exiting'
[galaxy => ~]$ cat secondary.sh
#!/bin/sh

echo 'Secondary script'
echo 'Secondary script generating an error'
false
echo 'Secondary script - should not be reached if sourced by primary.sh'
[galaxy => ~]$ ./primary.sh
Primary script
Secondary script
Secondary script generating an error
Got an error from the secondary script
Primary script exiting
[galaxy => ~]$