Public bug reported:
In a nutshell, if the package command-not-found is removed, but not
purged, sourcing this file leads to silent failures if a command is not
found.
I don't use Ubuntu, but I assume that the file bash_command_not_found in
the bzr repository is installed to /etc
./x is your bash_command_not_found with /usr/ replaced by /ur/ to
simulate that the packages is removed but not purged.
I use a self written printexitvalue (see tcsh and zsh), which prints the
line "bash: exit $?" via $PROMPT_COMMAND - this is unrelated to the bug,
but shown in the output below.
$ unset -f command_not_found_handle
$ cat x
command_not_found_handle() {
if [ -x /ur/lib/command-not-found ]; then
/ur/lib/command-not-found -- "$1"
return $?
else
return 127
fi
}
$ foo
bash: foo: command not found
bash: exit 127
$ . ./x
$ foo
bash: exit 127
$
As you can see, trying to run the non-available command foo results in
no output (except of the one I do in $PROMPT_COMMAND) and correctly
fails with exit code 127. It does not print "bash: foo: command not
found", as it should.
command_not_found_handle() is not command_not_found_handler() (note the
trailing 'r' in the word handler, that's not in the word handle). man
bash (for the former function) and man zshall (for the latter function)
contain the glory details how both functions work and how they differ.
If /usr/lib/command-not-found is available, your
command_not_found_handle() implementation behaves as it should, but if
/usr/lib/command-not-found is not available it behaves as zsh's
command_not_found_handler() should, but not as a
command_not_found_handle() should.
An untested, but presumably correct implementation, except of the
unconditional overwriting of the function (I don't know how to prevent
this in bash properly), and returning 127 when it should return 126 (see
man p exec), based on /etc/zsh_command_not_found, is shown below.
Please replace two leading spaces with a tab, four leading spaces with
two tabs and so on; and don't replace "|| return $?" with "\nreturn $?",
in case someone uses set -e interactively. I quoted the words return and
builtin to guard against weird alias definitions (I did not do this in
the zsh snipppet because, in general, I expect zsh users to have at
least basic shell knowledge, and sometimes zsh users do ugly things on
purpose.
# (c) Zygmunt Krynicki 2007,
# Licensed under GPL, see COPYING for the whole text
#
# This script will look-up command in the database and suggest
# installation of packages available from the repository
if [[ -x /usr/lib/command-not-found ]] ; then
command_not_found_handle() {
[[ -x /usr/lib/command-not-found ]] || {
\builtin printf >&2 'bash: %scommand not found\n' ${1+"$1: "}
\return 127
}
/usr/lib/command-not-found -- ${1+"$1"} || \return $?
}
fi
** Affects: command-not-found (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/1479805
Title:
/etc/bash_command_not_found is utterly broken
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