Bash, call a function sourced from a script?

Question

Say I have 2 scripts

test1.sh

#!/bin/sh
. ./test2.sh
foo

test2.sh

#!/bin/sh
foo(){
  echo "bar"
}

If I call first script it is ok

$ ./test1.sh
bar

But if I try to call foo after that it will not work.

$ foo
bash: foo: command not found

Answer 1

When you execute ./test1.sh, a subprocess is spawned. When test1.sh sources test2.sh, only the context of that subprocess is modified when foo() is defined. As soon as test1.sh completes, the subprocess terminates and your interactive shell has no knowledge of foo().