mirror: Apply "known differences" before comparing files on kernel sync
At the end of the sync up process, sync-kernel.sh compares the resulting
files in the mirror with the reference files in the Linux repository,
and highlights any difference. There are _always_ differences to check,
because a few files (e.g. src/Makefile) differ between the mirror and
the kernel repository. The issue, with the generated diff, is that it is
easy to miss a new, relevant difference that would be "hidden" in the
middle of the other "known" changes.
To help detect the relevant changes, hide the known differences by first
attempting to apply (temporarily) a patch containing these known
differences to the mirror, so that they are ignored when comparing the
files with their version from the kernel.
Signed-off-by: Quentin Monnet <[email protected]>
diff --git a/scripts/sync-kernel.sh b/scripts/sync-kernel.sh
index 366cbd3..643711a 100755
--- a/scripts/sync-kernel.sh
+++ b/scripts/sync-kernel.sh
@@ -360,6 +360,14 @@
FILTER_BRANCH_SQUELCH_WARNING=1 git filter-branch -f --tree-filter "${BPFTOOL_TREE_FILTER}" ${VIEW_TAG}^..${VIEW_TAG}
FILTER_BRANCH_SQUELCH_WARNING=1 git filter-branch -f --subdirectory-filter __bpftool ${VIEW_TAG}^..${VIEW_TAG}
git ls-files -- ${BPFTOOL_VIEW_PATHS[@]} | grep -v -E "${LINUX_VIEW_EXCLUDE_REGEX}" > ${TMP_DIR}/linux-view.ls
+# Before we compare each file, try to apply to the mirror a patch containing the
+# expected differences between the two repositories; this is to avoid checking
+# "known" differences visually and taking the risk of missing a new, relevant
+# differences.
+echo "Patching to account for expected differences..."
+patch -d "${LINUX_ABS_DIR}" -p0 -f --reject-file=- --no-backup-if-mismatch < "${GITHUB_ABS_DIR}/scripts/sync-kernel-expected-diff.patch" || true
+git add -u
+git commit -m 'tmp: apply expected differences to compare github/kernel repos' || true
cd_to ${BPFTOOL_REPO}
git ls-files -- ${BPFTOOL_VIEW_PATHS[@]} | grep -v -E "${BPFTOOL_VIEW_EXCLUDE_REGEX}" > ${TMP_DIR}/github-view.ls
@@ -374,11 +382,24 @@
CONSISTENT=0
fi
done
+echo ""
if ((${CONSISTENT} == 1)); then
echo "Great! Content is identical!"
else
ignore_inconsistency=n
echo "Unfortunately, there are some inconsistencies, please double check."
+ echo "Some of them may come from patches in bpf tree but absent from bpf-next."
+ echo "Note: I applied scripts/sync-kernel-expected-diff.patch before checking,"
+ echo "to account for expected changes. If this patch needs an update,"
+ echo "you can do it now with:"
+ echo "------"
+ echo " (cd \"${LINUX_ABS_DIR}\" && git -c advice.detachedHead=false checkout HEAD~)"
+ echo " for f in \$(cat \"${TMP_DIR}/linux-view.ls\"); do"
+ echo " diff -u --label \"\${f}\" --label \"\${f}\" \\"
+ echo " \"${LINUX_ABS_DIR}/\${f}\" \\"
+ echo " \"${GITHUB_ABS_DIR}/\${f}\""
+ echo " done > \"${GITHUB_ABS_DIR}/scripts/sync-kernel-expected-diff.patch\""
+ echo "------"
read -p "Does everything look good? [y/N]: " ignore_inconsistency
case "${ignore_inconsistency}" in
"y" | "Y")
