Implement `set -e` alternative about xonsh HOT 5 OPEN

Indeed, $RAISE_SUBPROC_ERROR is to raise error in any case when any command fails but set -e treat the line as whole:

Exit immediately if a pipeline (see Pipelines), which may consist of a single simple command (see Simple Commands), a list (see Lists of Commands), or a compound command (see Compound Commands) returns a non-zero status.

So we need additional setting e.g. $XONSH_RAISE_SUBPROC_PIPELINE_ERROR to do the same as bash. PR is welcome!

from xonsh.

JFYI. For this:

set -e
ls nonono || true     # false || true
echo "success"

the xonsh equvalent for now is this:

$RAISE_SUBPROC_ERROR = True
try:
    ls nonono
except:               # OR except subprocess.CalledProcessError:
    pass
echo "success"

from xonsh.

You can create syntax sugar for this using macro call:

import subprocess
def ignore_error(cmd):
    """Ignore failing of the command."""
    try:
        execx(cmd)
    except subprocess.CalledProcessError:
        pass
        
        
$RAISE_SUBPROC_ERROR = False      
ignore_error!(echo 1 and (ls nonono or echo 2))
echo success
# success
        
$RAISE_SUBPROC_ERROR = True        
ignore_error!(echo 1 and (ls nonono or echo 2))
echo success
# success

from xonsh.

I'm aware that I can do a try-except block to ignore errors, though that still doesn't help with the underlying problem of boolean logic being broken with subprocess return codes.

from xonsh.

I figured this out the case.

What bash doing. In fact it implicitly overrides the execution of a logical expression and the execution of process. If we run echo 1 and ls nonono the result of this logical will be treated as "return code" and if it's not 0 and set -e the error will be raised.

In xonsh we have separation between process running and logical expression running. If we run echo 1 and ls nonono we have 2 separate processes and logical expression and RAISE_SUBPROC_ERROR will work on process level.

In fact in this issue was requested an additional mode like RAISE_COMMAND_ERROR that will work for the whole logical expression.

Current behavior:

$RAISE_SUBPROC_ERROR=False
echo 1 and (ls no or echo 2)
# run logical: `echo 1`, `ls no`, `echo 2`.
__xonsh__.history[-1]
# rtn=0
echo 1 and (echo 2 or ls no)
# run logical: `echo 1`, `echo 2`.
__xonsh__.history[-1]
# rtn=0

$RAISE_SUBPROC_ERROR=True
echo 1 and (ls no or echo 2)
# run logical: `echo 1`, `ls no` (raise and stop).
__xonsh__.history[-1]
# rtn=2
echo 1 and (echo 2 or ls no)
# run logical: `echo 1`, `echo 2`.
__xonsh__.history[-1]
# rtn=0

from xonsh.