automatic unsetting of inherit_errexit with function calls

[crstml]

Hello all,

Let's assume the following script named test-subst-and-error.sh:

 1  func()
 2  {
 3      echo "entering func"
 4      : $-
 5      bash -c "echo XXXXXXXX; exit 8"
 6      echo "exiting func"
 7  }
 8
 9   OUTPUT=$(cat non-existing-file.txt)
10   # OUTPUT=$(func)
11
12   echo "OUTPUT: '${OUTPUT}'"

Here are 2 execution cases:

Case 1:
     - line 9 active;  line 10 commented
     - execution command: bash -e test-subst-and-error.sh

     - the statement in the line 12 is NOT reached.

Case 2:
     - line 9 commented; line 10 active
     - execution command: bash -e test-subst-and-error.sh

     - the statement in the line 12 is reached.


Why is there any difference between the case 1 and the case 2?

According to may interpretation of the manual, in a subshell -e
should be automatically unset (unless in posix mode). In reality
I would prefer to not have an automatic unsetting of errexit,
but this is another topic.

My only question is: why in the case 1 when external program
is called errexit is not not automatically disabled but it is
disabled when a function is called?

Thank you in advance.
Cristian


P.S: As expected, when bash is started without -e the execution
     does not stop which is normal.