[OE-core] [PATCH] terminal.bbclass: use var-SHELL as the shebang of wrapper script

[Andre McCurdy]

On Tue, Sep 4, 2018 at 7:16 PM, Hongxu Jia <hongxu.jia at windriver.com> wrote:
> On 2018年09月05日 09:59, Andre McCurdy wrote:
>>
>> On Tue, Sep 4, 2018 at 6:02 PM, Hongxu Jia <hongxu.jia at windriver.com>
>> wrote:
>>>
>>> On 2018年09月05日 03:14, Andre McCurdy wrote:
>>>>
>>>> Maybe I'm missing something, but what's the advantage of using SHELL
>>>> to run this little wrapper script rather than hardcoding /bin/sh ?
>>>>
>>>> Task shell scripts created by bitbake use hardcoded /bin/sh (see
>>>> bitbake/lib/bb/build.py -> shell_trap_code())
>>>
>>> Keep align with the devshell as the comments mentioned above
>>
>> Yeah, I've read the comments. I still don't really understand why.
>>
>>> The devshell.bbclass set var-SHELL to var-DEVSHELL, and terminal.bbclass
>>> initial var-SHELL with `bash'. Keep sync with it, use var-SHELL rather
>>> than hardcoded `/bin/sh' as the shebang of wrapper script.
>>>
>>> On Ubuntu host, default shell is dash (/bin/sh -> dash), even though
>>> we assign var-SHELL with `/bin/bash', the wrapper script is still
>>> dashism.
>>
>> What exactly is a dashism?
>
>
> In another word, it does not support bashism.
>
> Here is a case which `export -f' is bashism although
>
> devshell using bash, but /bin/sh -> dash
>
> [case]
>
> function foobar { echo foobar; };
>  export -f foobar
> bitbake -c devshell virtual/kernel
>
> [case]
>
>
> BTW, I've sent anther patch to fix it `[OE-core] [PATCH]
> devshell.bbclass/terminal.bbclass: add a shell check at devshell'

OK, but run.do_terminal.xxx is a trivial wrapper which (apart from
exporting environment variables) just contains something like:

  do_terminal() {
  exec pseudo /bin/bash
  }

  do_terminal

I'm not sure what the problem is running that with /bin/sh, regardless
of whether /bin/sh points to bash or dash?