Re: [kvm-unit-tests RFC PATCH 01/17] Add initial shellcheck checking

[Andrew Jones <andrew.jones@linux.dev>]

On Fri, Apr 05, 2024 at 07:00:33PM +1000, Nicholas Piggin wrote:
> This adds a basic shellcheck sytle file, some directives to help
> find scripts, and a make shellcheck target.
> 
> When changes settle down this could be made part of the standard
> build / CI flow.
> 
> Suggested-by: Andrew Jones <andrew.jones@linux.dev>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  .shellcheckrc       | 32 ++++++++++++++++++++++++++++++++
>  Makefile            |  4 ++++
>  README.md           |  2 ++
>  scripts/common.bash |  5 ++++-
>  4 files changed, 42 insertions(+), 1 deletion(-)
>  create mode 100644 .shellcheckrc
> 
> diff --git a/.shellcheckrc b/.shellcheckrc
> new file mode 100644
> index 000000000..2a9a57c42
> --- /dev/null
> +++ b/.shellcheckrc
> @@ -0,0 +1,32 @@
> +# shellcheck configuration file
> +external-sources=true
> +
> +# Optional extras --  https://www.shellcheck.net/wiki/Optional
> +# Possibilities, e.g., -
> +# quote‐safe‐variables
> +# require-double-brackets
> +# require-variable-braces
> +# add-default-case
> +
> +# Disable SC2004 style? I.e.,
> +# In run_tests.sh line 67:
> +#            if (( $unittest_run_queues <= 0 )); then
> +#                  ^------------------^ SC2004 (style): $/${} is unnecessary on arithmetic variables.
> +disable=SC2004

I vote keep disabled. The problem pointed out in the wiki can be handled
with ($a), similar to how one handles variables to C preprocessor macros.

> +
> +# Disable SC2034 - config.mak contains a lot of these unused variable errors.
> +# Maybe we could have a script extract the ones used by shell script and put
> +# them in a generated file, to re-enable the warning.
> +#
> +# In config.mak line 1:
> +# SRCDIR=/home/npiggin/src/kvm-unit-tests
> +# ^----^ SC2034 (warning): SRCDIR appears unused. Verify use (or export if used externally).
> +disable=SC2034

Maybe we should export everything in config.mak.

> +
> +# Disable SC2086 for now, double quote to prevent globbing and word
> +# splitting. There are lots of places that use it for word splitting
> +# (e.g., invoking commands with arguments) that break. Should have a
> +# more consistent approach for this (perhaps use arrays for such cases)
> +# but for now disable.
> +# SC2086 (info): Double quote to prevent globbing and word splitting.
> +disable=SC2086

Agreed. We can cross this bridge later.

> diff --git a/Makefile b/Makefile
> index 4e0f54543..4863cfdc6 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -141,6 +141,10 @@ cscope:
>  		-name '*.[chsS]' -exec realpath --relative-base=$(CURDIR) {} \; | sort -u > ./cscope.files
>  	cscope -bk
>  
> +.PHONY: shellcheck
> +shellcheck:
> +	shellcheck -a run_tests.sh */run */efi/run scripts/mkstandalone.sh
> +
>  .PHONY: tags
>  tags:
>  	ctags -R
> diff --git a/README.md b/README.md
> index 6e82dc225..77718675e 100644
> --- a/README.md
> +++ b/README.md
> @@ -193,3 +193,5 @@ with `git config diff.orderFile scripts/git.difforder` enables it.
>  
>  We strive to follow the Linux kernels coding style so it's recommended
>  to run the kernel's ./scripts/checkpatch.pl on new patches.
> +
> +Also run make shellcheck before submitting a patch.

which touches Bash scripts.


> diff --git a/scripts/common.bash b/scripts/common.bash
> index ee1dd8659..3aa557c8c 100644
> --- a/scripts/common.bash
> +++ b/scripts/common.bash
> @@ -82,8 +82,11 @@ function arch_cmd()
>  }
>  
>  # The current file has to be the only file sourcing the arch helper
> -# file
> +# file. Shellcheck can't follow this so help it out. There doesn't appear to be a
> +# way to specify multiple alternatives, so we will have to rethink this if things
> +# get more complicated.
>  ARCH_FUNC=scripts/${ARCH}/func.bash
>  if [ -f "${ARCH_FUNC}" ]; then
> +# shellcheck source=scripts/s390x/func.bash
>  	source "${ARCH_FUNC}"
>  fi
> -- 
> 2.43.0
>

Other than the extension to the sentence in the README,

Reviewed-by: Andrew Jones <andrew.jones@linux.dev>

Thanks,
drew