style: address shellcheck warnings

[reubenmiller]

Addressing the warnings raised by shellcheck.

Using shellcheck (slightly) improves the style consistency and reduces the chance of subtle errors.

There are still two shellcheck warnings for missing shebangs (in mk/package.sh and mk/publish.sh, however looking at the scripts it seems these might be for windows environments running MinGW, where shebangs might be incompatible.

[briansmith]

Thanks. It would be great if somebody who is more familiar with shell scripting could review this. There are some things that seems strange to me. I'll point out a couple.

[briansmith]

This looks weird. I wonder if there's a better way of doing it. Maybe removing the "outermost"-looking double quotes, similar to the target_upper=... line above?

[reubenmiller]

Having outer quotes is fine because $() starts a new context (see SC2086) where the quoting is processed independently, so no escaping is required. However for consistency, I'll remove the outer quotes as it has not effect on the variable assignment.

[reubenmiller]

Resolved by 9a18e6f

[briansmith]

It looks weird to be inconsistent with having the double quotes only around the variable usage in "${llvm_root}"/llvm-profdata but then less tight in "$coverage_dir/$basename.profraw" and "$coverage_dir/$basename.profdata". Maybe I'm missing something, but some more consistency would be nice.

[reubenmiller]

Resolved by 31dc1e6.

Though I was thinking about normalizing the usage of ${example} vs $example using the following rules:

• Use $example when the variable is not being without additional characters or variable modifiers (e.g. ${example:-default_value}

  value="$example"
  if [ "$example" = "other" ]; then echo matches; fi

• Use ${example} otherwise, e.g. +${example}, my/path/${example} to make it more (visually) obvious that a string is being built from mixing strings with variables.

  value="+${value}"
  value2="${value:-default}"
  "${bin}/path/myexec" run

@briansmith Are you ok with this?