Update wiki around SC2213 to include examples of long option names handling with getopts

[andyfeller]

For bugs

• Rule Id (if any, e.g. SC1000): SC2213
• My shellcheck version (shellcheck --version or "online"): 0.7.2
• The rule's wiki page does not already cover this (e.g. https://shellcheck.net/wiki/SC2086)
• I tried on https://www.shellcheck.net/ and verified that this is still a problem on the latest commit

For new checks and feature suggestions

• https://www.shellcheck.net/ (i.e. the latest commit) currently gives no useful warnings about this
• I searched through https://github.com/koalaman/shellcheck/issues and didn't find anything related

Here's a snippet or screenshot that shows the problem:

#!/bin/sh

LOCK_REPOSITORIES=false

while getopts "af:hlo:r:t:-:" OPT; do
  if [ "$OPT" = "-" ]; then   # long option: reformulate OPT and OPTARG
    OPT="${OPTARG%%=*}"       # extract long option name
    OPTARG="${OPTARG#$OPT}"   # extract long option argument (may be empty)
    OPTARG="${OPTARG#=}"      # if long option argument, remove assigning `=`
  fi

  case "$OPT" in
    lock-repositories)
      LOCK_REPOSITORIES=true
      ;;
  esac
done

Here's what shellcheck currently says:

In ... line 60:
lock-repositories)
^---------------^ SC2214: This case is not specified by getopts.

Here's what I wanted or expected to see:

I would like to see https://github.com/koalaman/shellcheck/wiki/SC2213 containing an example of how it recommends long options being handled as it appears v0.7.2 release has logic around them. I know this is a very gray area, so I'm just focusing on how to do long option names in a way that passes shellcheck 👍

[koalaman]

getopts does not support long options, and this is an interesting way around that that I haven't seen before. I've updated the check to bail if it sees the getopts variable being modified, and added some suggestions to the wiki like using getopt (no "s"), or checking in a -) branch. Thanks!

(The getopts code you link to is unrelated, it's what ShellCheck uses internally for analysis purposes)

[andyfeller]

Thanks for the follow up and insight, @koalaman! 🙇 Really happy I ran into this project and appreciate the work you're doing.. Let me grok the updates and try them out.