Bug 374875 – sys-apps/openrc: warn about removal of bash array support

• Product: Gentoo Hosted Projects
• Status: RESOLVED FIXED

[Description William Hubbs 2011-07-11 17:17:50 UTC]

All,

It was pointed out to me that someone is using bash arrays in their
/etc/conf.d/net file with openrc.

After investigation, I have discovered that even though our
documentation (net.example) and the migration guide say that we do not
support bash arrays, we do in parts of oldnet.

I would like to remove that support since if users have followed the
migration guide they are no longer using it.

[Comment 1 William Hubbs 2011-07-11 17:21:57 UTC]

Another reason to remove this is that openrc should only have posix
compatible features, and bash arrays do not fit that design.

[Comment 2 David Leverton 2011-07-11 21:04:56 UTC]

If it's not documented, surely that's a problem with the documentation? ;-)

Note that this issue caused a bit of drama a few years back, notably http://marc.info/?l=gentoo-dev&w=2&r=1&s=baselayout+bash+arrays&q=b and http://marc.info/?t=117085436800005&r=1&w=2 (there was even talk of forking baselayout so the array and POSIX people could both be happy, until I came up with (almost) the current solution), so I'd suggest proceeding with caution if you really want to do this.

[Comment 3 William Hubbs 2011-07-12 20:38:05 UTC]

Created attachment 279911 [details]
0001-add-error-messages-for-the-use-of-bash-arrays.patch

All,

here is the first patch I would like to add to deal with bash arrays.
This patch generates error message when a bash array is detected to
encourage users not to use them.

What are your thoughts?

William

[Comment 4 SpanKY 2011-07-12 21:05:36 UTC]

s/eerror/ewarn/

and quote the string:
    ewarn "...."

[Comment 5 William Hubbs 2011-07-14 17:24:40 UTC]

Mike,

the changes you suggested have been made and this has been pushed as
commit e3b02ab.

Should we retitle this bug and close it now and open another bug later
to officially remove the bash array support?

[Comment 6 SpanKY 2011-07-14 17:29:01 UTC]

that's fine.  we'll need ebuild updates before we can remove support anyways.

[Comment 7 Scott Jones 2017-11-02 19:10:55 UTC]

Sorry to revive and old bug, but it's not "closed".  Is this still open for discussion?

Other than posixness, is there a technical reason why openrc shouldn't allow bash arrays?  I was working on updating an init script and its conf to use associative arrays, and found that it just wouldn't work through openrc.  It also didn't trigger an error (as this bug report suggests it should have).

To run multiple instances of an init (sort of like net does), associative arrays make for a much more elegant and intuitive configuration.  I have worked around it by using eval, but that solution just makes me feel icky... even though the end result does work.

The below examples obviously need more stuff to make them work, but the POSIX route requires more variable manipulation to achieve the same result as what modern bash supports.

For example:
init.d/dummy
init.d/dummy -> dummy.blah1
init.d/dummy -> dummy.blah2

Associative:
echo ${DUMMY_PORT[${RC_SVCNAME#*.}]}

POSIX:
DUMMY_INSTANCE="${RC_SVCNAME#*.}"
echo $(eval \${DUMMY_PORT_${DUMMY_INSTANCE^^}})


conf.d/dummy:

Associative:
DECLARE -A DUMMY_PORT
DUMMY_PORT=12345         # this gets assigned as DUMMY_PORT[0]
DUMMY_PORT[blah1]=12346
DUMMY_PORT[blah2]=12347

POSIX:
DUMMY_PORT=12345
DUMMY_PORT_BLAH1=12346
DUMMY_PORT_BLAH2=12347


The associative route would allow some fun stuff like this in the conf file too:
DECLARE -A DUMMY_PORT=("[blah1]" "[blah2]")
DUMMY_BASE_PORT=12345
__PORT=${DUMMY_BASE_PORT}
for i in ${!DUMMY_PORT[@]} ; do DUMMY_PORT[$i]=$(( __PORT++ )) ; done
DUMMY_PORT=${DUMMY_BASE_PORT}

# because I don't care what the port # is, each daemon just needs its own port

[Comment 8 Robin Johnson 2017-11-02 19:45:56 UTC]

(In reply to Scott Jones from comment #7)
> Sorry to revive and old bug, but it's not "closed".  Is this still open for
> discussion?
OpenRC needs to be able to run without bash present on the system, and init scripts cannot assume that their environment is full bash. 

> Other than posixness, is there a technical reason why openrc shouldn't allow
> bash arrays?  I was working on updating an init script and its conf to use
> associative arrays, and found that it just wouldn't work through openrc.  It
> also didn't trigger an error (as this bug report suggests it should have).
That should have triggered an error, can you please report it as a new bug?

> 
> To run multiple instances of an init (sort of like net does), associative
> arrays make for a much more elegant and intuitive configuration.  I have
> worked around it by using eval, but that solution just makes me feel icky...
> even though the end result does work.
Look at mysql-init-scripts, they support multiple instances fine without arrays (admittedly, they did use arrays before, but moved away from them).

[Comment 9 Scott Jones 2017-11-02 21:57:21 UTC]

Thanks! I'll check out mysql-init-scripts and create a bug report for how to reproduce what I was doing that didn't generate an error.  I'll also make sure my new deluge init script is posix compliant before posting it  :)