Trap does not check for the first argument being an unsigned integer

[jasom]

From the POSIX spec:

If the first operand is an unsigned decimal integer, the shell shall treat all operands as conditions, and shall reset each condition to the default value. Otherwise, if there are operands, the first is treated as an action and the remaining as conditions.

I really don't want to know what buggy ill-specified behavior in an old Unix shell caused it to be standardized this way, but other shells appear to implement this:

$ for sh in bash dash ksh osh; do $sh -c 'trap "echo hi" EXIT; trap 1 EXIT'; done
  1
  ^
[ trap word at ? ]:1

[??? no location ???] '1' not found (OILS-ERR-100)

[andychu]

Oh weird, never heard that rule ...

This may need some more work in https://github.com/oils-for-unix/oils/blob/master/frontend/signal_gen.py

[jasom]

This should only require work in https://github.com/oils-for-unix/oils/blob/master/builtin/trap_osh.py to call RemoveUser{Trap|Hook} when the first argument is an unsigned integer, no?

[andychu]

Oh maybe ... the spec tests can answer that. The text is hard for me to parse

Are you interested in adding some tests and maybe implementing it? If it is only clearing traps it should be straightforward

$ test/spec.sh builtin-trap
builtin-trap.test.sh
case    line    dash    bash    mksh    ash     osh
  0       6     pass    pass    pass    pass    pass    trap accepts/ignores --
  1      14     pass    pass    pass    pass    ok      trap 'echo hi' KILL (regression test, caught by smoosh suite)
  2      40     pass    pass    pass    pass    pass    Register invalid trap
  3      44     pass    pass    pass    pass    pass    Remove invalid trap

in spec/builtin-trap.test.sh

https://github.com/oils-for-unix/oils/wiki/Spec-Tests