On Sun 25 Dec 2022 00:51:38 GMT, Masahiro Yamada wrote:
> The top .gitignore comments about how to detect files breaking
> .gitignore rules, but people rarely care about it.
> 
> Add a new W=1 warning to detect files that are tracked but ignored by
> git. If git is not installed or the source tree is not tracked by git
> at all, this script does not print anything.
> 
> Running it on the v6.1 kernel detected the following:
> 
>   $ make W=1 misc-check
>   Documentation/devicetree/bindings/.yamllint: warning: ignored by one of the .gitignore files
>   drivers/clk/.kunitconfig: warning: ignored by one of the .gitignore files
>   drivers/gpu/drm/tests/.kunitconfig: warning: ignored by one of the .gitignore files
>   drivers/hid/.kunitconfig: warning: ignored by one of the .gitignore files
>   fs/ext4/.kunitconfig: warning: ignored by one of the .gitignore files
>   fs/fat/.kunitconfig: warning: ignored by one of the .gitignore files
>   kernel/kcsan/.kunitconfig: warning: ignored by one of the .gitignore files
>   lib/kunit/.kunitconfig: warning: ignored by one of the .gitignore files
>   mm/kfence/.kunitconfig: warning: ignored by one of the .gitignore files
>   tools/testing/selftests/arm64/tags/.gitignore: warning: ignored by one of the .gitignore files
>   tools/testing/selftests/arm64/tags/Makefile: warning: ignored by one of the .gitignore files
>   tools/testing/selftests/arm64/tags/run_tags_test.sh: warning: ignored by one of the .gitignore files
>   tools/testing/selftests/arm64/tags/tags_test.c: warning: ignored by one of the .gitignore files
> 
> These are ignored by the '.*' or 'tags' in the top .gitignore, but
> there is no rule to negate it.
> 
> You might be tempted to do 'git add -f' but I want to have the real
> issue fixed (by fixing a .gitignore, or by renaming files, etc.).
> 
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> ---
> 
> Changes in v2:
>   - Add $(srctree)/ to make it work with O=
> 
>  Makefile           |  6 ++++++
>  scripts/misc-check | 19 +++++++++++++++++++
>  2 files changed, 25 insertions(+)
>  create mode 100755 scripts/misc-check
> 
> diff --git a/Makefile b/Makefile
> index 44239352d2bf..f6ff8f77a669 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1852,6 +1852,12 @@ rust-analyzer:
>  # Misc
>  # ---------------------------------------------------------------------------
>  
> +PHONY += misc-check
> +misc-check:
> +	$(Q)$(srctree)/scripts/misc-check
> +
> +all: misc-check
> +
>  PHONY += scripts_gdb
>  scripts_gdb: prepare0
>  	$(Q)$(MAKE) $(build)=scripts/gdb
> diff --git a/scripts/misc-check b/scripts/misc-check
> new file mode 100755
> index 000000000000..bf68712d1ac1
> --- /dev/null
> +++ b/scripts/misc-check
> @@ -0,0 +1,19 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0-only
> +
> +set -e
> +
> +# Detect files that are tracked but ignored by git. This is checked only when
> +# ${KBUILD_EXTRA_WARN} contains 1, git is installed, and the source tree is
> +# tracked by git.
> +check_tracked_ignored_files () {
> +	case "${KBUILD_EXTRA_WARN}" in
> +	*1*) ;;
> +	*) return;;
> +	esac
> +
> +	git ls-files -i -c --exclude-per-directory=.gitignore 2>/dev/null |
> +		sed 's/$/: warning: ignored by one of the .gitignore files/' >&2

I like that check.  It doesn't work with O=...; works for me with 
something like:

  git ${abs_srctree:+-C "${abs_srctree}"} ls-files ...

Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>