kbuild: give up untracked files for source package builds

When the source tree is dirty and contains untracked files, package
builds may fail, for example, when a broken symlink exists, a file
path contains whitespaces, etc.

Since commit 05e96e96a315 ("kbuild: use git-archive for source package
creation"), the source tarball only contains committed files because
it is created by 'git archive'. scripts/package/gen-diff-patch tries
to address the diff from HEAD, but including untracked files by the
hand-crafted script introduces more complexity. I wrote a patch [1] to
make it work in most cases, but still wonder if this is what we should
aim for.

To simplify the code, this patch just gives up untracked files. Going
forward, it is your responsibility to do 'git add' for what you want in
the source package. The script shows a warning just in case you forgot
to do so. It should be checked only when building source packages.

[1]: https://lore.kernel.org/all/CAK7LNAShbZ56gSh9PrbLnBDYKnjtTkHMoCXeGrhcxMvqXGq9=g@mail.gmail.com/2-0001-kbuild-make-package-builds-more-robust.patch

Fixes: 05e96e96a315 ("kbuild: use git-archive for source package creation")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

1 files changed, 27 insertions, 35 deletions

diff --git a/scripts/package/gen-diff-patch b/scripts/package/gen-diff-patch
index f842ab50a780..8a98b7bb78a0 100755
--- a/scripts/package/gen-diff-patch
+++ b/scripts/package/gen-diff-patch
@@ -1,44 +1,36 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0-only
 
-diff_patch="${1}"
-untracked_patch="${2}"
-srctree=$(dirname $0)/../..
+diff_patch=$1
 
-rm -f ${diff_patch} ${untracked_patch}
+mkdir -p "$(dirname "${diff_patch}")"
 
-if ! ${srctree}/scripts/check-git; then
-	exit
-fi
-
-mkdir -p "$(dirname ${diff_patch})" "$(dirname ${untracked_patch})"
+git -C "${srctree:-.}" diff HEAD > "${diff_patch}"
 
-git -C "${srctree}" diff HEAD > "${diff_patch}"
-
-if [ ! -s "${diff_patch}" ]; then
-	rm -f "${diff_patch}"
+if [ ! -s "${diff_patch}" ] ||
+   [ -z "$(git -C "${srctree:-.}" ls-files --other --exclude-standard | head -n1)" ]; then
 	exit
 fi
 
-git -C ${srctree} status --porcelain --untracked-files=all |
-while read stat path
-do
-	if [ "${stat}" = '??' ]; then
-
-		if ! diff -u /dev/null "${srctree}/${path}" > .tmp_diff &&
-			! head -n1 .tmp_diff | grep -q "Binary files"; then
-			{
-				echo "--- /dev/null"
-				echo "+++ linux/$path"
-				cat .tmp_diff | tail -n +3
-			} >> ${untracked_patch}
-		fi
-	fi
-done
-
-rm -f .tmp_diff
-
-if [ ! -s "${diff_patch}" ]; then
-	rm -f "${diff_patch}"
-	exit
-fi
+# The source tarball, which is generated by 'git archive', contains everything
+# you committed in the repository. If you have local diff ('git diff HEAD'),
+# it will go into ${diff_patch}. If untracked files are remaining, the resulting
+# source package may not be correct.
+#
+# Examples:
+#  - You modified a source file to add #include "new-header.h"
+#    but forgot to add new-header.h
+#  - You modified a Makefile to add 'obj-$(CONFIG_FOO) += new-dirver.o'
+#    but you forgot to add new-driver.c
+#
+# You need to commit them, or at least stage them by 'git add'.
+#
+# This script does not take care of untracked files because doing so would
+# introduce additional complexity. Instead, print a warning message here if
+# untracked files are found.
+# If all untracked files are just garbage, you can ignore this warning.
+echo >&2 "============================ WARNING ============================"
+echo >&2 "Your working tree has diff from HEAD, and also untracked file(s)."
+echo >&2 "Please make sure you did 'git add' for all new files you need in"
+echo >&2 "the source package."
+echo >&2 "================================================================="