.github: Reflect more kernel versions in the changelog

It happens that kernel update PRs are created faster than we merge
them. In such case we create version gaps in the changelog. Remedy
that by adding links to all the released kernel versions between the
current one and the just released one.

sdk_container/src/third_party/coreos-overlay/.github/workflows/common.sh

@@ -71,15 +71,36 @@ function regenerate_manifest() {
   popd || exit
 }
 
+function join_by() {
+  local delimiter="${1-}"
+  local first="${2-}"
+  if shift 2; then
+    printf '%s' "${first}" "${@/#/${delimiter}}";
+  fi
+}
+
 function generate_update_changelog() {
   local NAME="${1}"
   local VERSION="${2}"
   local URL="${3}"
   local UPDATE_NAME="${4}"
+  shift 4
+  local file="changelog/updates/$(date '+%Y-%m-%d')-${UPDATE_NAME}-update.md"
+  local -a old_links
 
   pushd "${SDK_OUTER_SRCDIR}/third_party/coreos-overlay" >/dev/null || exit
   if [[ -d changelog/updates ]]; then
-      echo "- ${NAME} ([${VERSION}](${URL}))" > "changelog/updates/$(date '+%Y-%m-%d')-${UPDATE_NAME}-update.md"
+    printf '%s %s ([%s](%s)' '-' "${NAME}" "${VERSION}" "${URL}" > "${file}"
+    if [[ $# -gt 0 ]]; then
+      echo -n ' (includes ' >> "${file}"
+      while [[ $# -gt 1 ]]; do
+        old_links+=( "[${1}](${2})" )
+        shift 2
+      done
+      printf '%s' "$(join_by ', ' "${old_links[@]}")" >> "${file}"
+      echo -n ')' >> "${file}"
+    fi
+    echo ')' >> "${file}"
   fi
   popd >/dev/null || exit
 }

sdk_container/src/third_party/coreos-overlay/.github/workflows/kernel-apply-patch.sh

@@ -36,19 +36,42 @@ done
 
 popd >/dev/null || exit
 
-if ! curl -sfA 'Chrome' -L 'http://www.google.com/search?hl=en&q=site%3Alwn.net+linux+'"${VERSION_NEW}" -o search.html; then
+function get_lwn_link() {
-  echo 'curl failed'
+  local LINUX_VERSION="${1}"
-  touch search.html
+  local url
-fi
-# can't use grep -m 1 -o … to replace head -n 1, because all the links
-# seem to happen in one line, so grep prints all the links in the line
-URL=$({ grep -o 'https://lwn.net/Articles/[0-9]\+' search.html || true ; } | head -n 1)
-if [[ ! "${URL}" ]]; then
-    URL="https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tag/?h=v${VERSION_NEW}"
-fi
-rm search.html
 
-generate_update_changelog 'Linux' "${VERSION_NEW}" "${URL}" 'linux'
+  if ! curl -sfA 'Chrome' -L 'http://www.google.com/search?hl=en&q=site%3Alwn.net+linux+'"${LINUX_VERSION}" -o search.html >&2; then
+    echo 'curl failed' >&2
+    touch search.html
+  fi
+  # can't use grep -m 1 -o … to replace head -n 1, because all the links
+  # seem to happen in one line, so grep prints all the links in the line
+  url=$({ grep -o 'https://lwn.net/Articles/[0-9]\+' search.html || true ; } | head -n 1)
+  if [[ ! "${url}" ]]; then
+    echo 'no valid links found in the search result' >&2
+    url="https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tag/?h=v${LINUX_VERSION}"
+  fi
+  rm search.html
+  echo "${url}"
+}
+
+PATCH_VERSION_OLD=${VERSION_OLD##*.}
+PATCH_VERSION_NEW=${VERSION_NEW##*.}
+
+PATCH_NUM=$((PATCH_VERSION_NEW - 1))
+
+OLD_VERSIONS_AND_URLS=()
+
+while [[ ${PATCH_NUM} -gt ${PATCH_VERSION_OLD} ]]; do
+  TMP_VERSION="${VERSION_SHORT}.${PATCH_NUM}"
+  TMP_URL=$(get_lwn_link "${TMP_VERSION}")
+  OLD_VERSIONS_AND_URLS+=( "${TMP_VERSION}" "${TMP_URL}" )
+  : $((PATCH_NUM--))
+done
+
+URL=$(get_lwn_link "${VERSION_NEW}")
+
+generate_update_changelog 'Linux' "${VERSION_NEW}" "${URL}" 'linux' "${OLD_VERSIONS_AND_URLS[@]}"
 
 generate_patches sys-kernel coreos-sources Kernel