On Sat, 2019-02-09 at 00:19 +0100, Michal Suchánek wrote:

If you look at bug lists in a distro such as Debian that sorts bugs per package you will find no shell is fully compliant. There is even a bug filed against dash for not failing to parse a perfectly valid shell code that bash and posh reject. There are even bugs filed pointing out differences in behavior and comments pointing out that both is compliant. Urgh. If one shell was good enough for the past 20 years let's keep its bugs and not introduce new ones unless there is *really* good reason backed by solid data.

Ack. And *if* we do so, we might as well simply define that /bin/sh is "bash", and consequently allow scripts and scriptlets to use the full feature set that bash has. Regards, Martin -- Dr. Martin Wilck , Tel. +49 (0)911 74053 2107 SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg) -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org

On Mon, 11 Feb 2019 12:18:29 +0100 Joerg Schilling wrote:

Michal Suchánek wrote:

...

If you look at bug lists in a distro such as Debian that sorts bugs per package you will find no shell is fully compliant. There is even a bug filed against dash for not failing to parse a perfectly valid shell code that bash and posh reject. There are even bugs filed pointing out differences in behavior and comments pointing out that both is compliant. Urgh. If one shell was good enough for the past 20 years let's keep its bugs and not introduce new ones unless there is *really* good reason backed by solid data.

Could you point to that bug please?

BTW:

- $(cmd) works best with bosh and mksh

- $((expr)) works best in bosh and ksh93 and has problems in bash and significant problems in dash.

In general however, the typical shell scripts on a platform should not cause related problems as the typical cases are handled correctly by most shells.

Here: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=382276 I have seen code artifically balancing case parentheses in our kernel build scripts and added some myself but I am not sure if the problem is in rpm spec parser or bash in this case. Thanks Michal -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org

Joerg Schilling wrote:

This is a bash bug that has been fixed in bash-5.

Let me give some background information: When David Korn introduced $(cmd) in ksh88, he thought that this could be implemented with a simple parser that just counts brackets. To permit this, he introduced the openning bracket: "switch ... case (x)" but it turns out that there are many other cases in the shell command language that need a recursive parser to support $(cmd), e.g. here documents that are par of a $(cmd) construct. Let me explain how bosh and mksh implement it: - First the parser is called with the string similar to: "cmd)" and told to stop parsing at a superfluous ")". - The syntax tree that is the output from the parser is then fed into the code that prints shell input from the binary tree (this has been introduced for printing functions. - This string is than kept in the syntax tree from the main parser call. If you do it this way, there is no need to fail in the parser... Jörg -- EMail:joerg@schily.net (home) Jörg Schilling D-13353 Berlin joerg.schilling@fokus.fraunhofer.de (work) Blog: http://schily.blogspot.com/ URL: http://cdrecord.org/private/ http://sf.net/projects/schilytools/files/' -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org

On Sat, 2019-02-09 at 14:36 +1030, Simon Lees wrote:

From a packaging perspective I don't mind so much either way if people want to put in the work. I have never rejected a review because of bashism's in a #!/bin/sh i'm guessing that I like many others simply don't know everything that is and isn't a bashism. I don't think that its reasonable to expect all developers to learn this. So if we did decide to enforce this kind of rule personally i'd like to see some form of automated checking whether its in rpmlint or something else so everyone isn't expected to just know. Until that point I don't think we should enforce it in reviews.

There's the "checkbashisms" script from Debian. It's available on factory as part of the "devscripts" package. I guess it should be possible to add that to a build check. We could even force it to run over any script with /bin/sh shebang... ... except that "checkbashisms" itself doesn't work under factory; it spits out all kinds of perl syntax problems. It's kind of ironic that this happens with just this script. Martin -- Dr. Martin Wilck , Tel. +49 (0)911 74053 2107 SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg) -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org