Follow up to #30563 too many quotes in maxima.py

[fbissey]

In #30563 one particular setting of MAXIMA used in sage-on-gentoo (maximax -l ecl) was extensively tested when applied to bin/sage. It unfortunately hadn't been so thoroughly tested in interfaces/maxima.py.

The __init__ method in maxima.py quote the variable MAXIMA when building the command for pexpect

                        command = '"{0}" -p "{1}"'.format(MAXIMA, STARTUP),

this leads the whole expression maxima -l ecl, with spaces, to be considered a command by pexpect. Removing the double quotes fix the problem and doesn't introduce any issue with more conventional values of MAXIMA.

[fbissey]

@strogdon, you may have seen that issue.

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New commits:

​8bef77e

Remove superfluous, and dangerous, double quotes.

[mkoeppe]

STARTUP should probably be quoted in case the directory contains whitespace.

[fbissey]

OK, I guess someone would have complained already if putting double quote there broke things.

I'll add that in fact sage-on-broken was potentially broken if you had maxima with sbcl and ecl installed - from the day interfaces/maxima.py started to use MAXIMA. So those improvements were really needed.

[fbissey]

Hum, then it may break things if MAXIMA is a path with spaces in it. A situation which could be common on windows.

[fbissey]

#30563 would already cause trouble if MAXIMA is a path with spaces in it because I didn't double quote in that ticket either. Which may mean no bots has that kind of configuration.

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

​a6f2b0c

Unqute MAXIMA so that "maxima -l ecl" is not considered one single command by pexpect

[fbissey]

If there are complaints I have a plan B.

[mkoeppe]

Well, since MAXIMA is used as the beginning of a shell command line (this could be documented...), one would be able to use shell quoting within the value of this variable.

[fbissey]

Replying to mkoeppe:

Well, since MAXIMA is used as the beginning of a shell command line (this could be documented...), one would be able to use shell quoting within the value of this variable.

Can you give a concrete example of your line of thought there? I am not completely sure of what your idea is and how to put it in practice.

[mkoeppe]

If maxima lies in /path with spaces/, then MAXIMA could be set to '"/path with spaces/maxima" -l ecl' and that would work with the current version on the branch.

Unrelated, but perhaps an improvement:

- command = '{0} -p "{1}"'.format(MAXIMA, STARTUP)
+ command = '{0} -p {1}'.format(MAXIMA, shlex.quote(STARTUP))

​https://docs.python.org/3/library/shlex.html

[fbissey]

Thanks for the explanation, that was helpful.

Using stuff like shlex more seems like a good idea to me and quote is available from 3.3 so it is ok to use. I'll redo the branch shortly.

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

​48fde54

Unquote MAXIMA to allow composite command and switch to shlex.quote for STARTUP.

[strogdon]

Does shlex have to be imported somewhere? interfaces/maxima.py fails here on s-o-g unless I explicitly import shlex.

[fbissey]

I'll confess that I thought it would be OK without import and it was foolish. I'll fix that.

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​c330344

Import shlex as it is needed

[fbissey]

Done.

[strogdon]

This works here.

@mkoeppe please add yourself if you see fit as I would never have thought of using shlex.