From d63954ba78501615220ab8887da615584647e7a5 Mon Sep 17 00:00:00 2001
From: Ariadne Conill <ariadne@ariadne.space>
Date: Mon, 12 Oct 2026 13:00:51 -0700
Subject: [PATCH] automation: do not fail backport retries when nothing needs
 retrying

retry-backports.sh filters the pull request numbers it collects through
grep under pipefail. When no mainline pull request is waiting and no
backport is stale, grep matches nothing and exits 1, so the script fails.
That is the usual case: the retry job has failed on every nightly run of
edera/6.18-lts since it was added, and lts-backport-merged.yml fails the
same way whenever a backport merges with nothing waiting.

Let an empty list through, and add tests for the script against a fake
gh, including the empty case.
---
 .github/scripts/retry-backports.sh            |  4 +-
 .github/scripts/tests/retry-backports.test.sh | 66 +++++++++++++++++++
 .github/workflows/automation-selftest.yml     |  3 +
 3 files changed, 72 insertions(+), 1 deletion(-)
 create mode 100755 .github/scripts/tests/retry-backports.test.sh

diff --git a/.github/scripts/retry-backports.sh b/.github/scripts/retry-backports.sh
index 723955972a35a8..5eaca535f0b508 100755
--- a/.github/scripts/retry-backports.sh
+++ b/.github/scripts/retry-backports.sh
@@ -12,6 +12,8 @@
 # read, and GITHUB_REPOSITORY.
 #
 # Usage: retry-backports.sh [--stale]
+#
+# Nothing to retry is the usual case and exits 0.
 
 set -euo pipefail
 
@@ -29,7 +31,7 @@ R=$GITHUB_REPOSITORY
 			-q ".[] | select(.headRefName | startswith(\"$PREFIX\")) | select(.mergeable == \"CONFLICTING\") | .headRefName" |
 			sed "s|^$PREFIX||"
 	fi
-} | grep -xE '[0-9]+' | sort -un | while read -r n; do
+} | { grep -xE '[0-9]+' || true; } | sort -un | while read -r n; do
 	echo "Dispatching the backport of #$n"
 	gh workflow run kernel-nightly.yml --repo "$R" --ref "$TARGET" -f backport_pr="$n"
 done
diff --git a/.github/scripts/tests/retry-backports.test.sh b/.github/scripts/tests/retry-backports.test.sh
new file mode 100755
index 00000000000000..5f900c5c1672b6
--- /dev/null
+++ b/.github/scripts/tests/retry-backports.test.sh
@@ -0,0 +1,66 @@
+#!/usr/bin/env bash
+# Tests for .github/scripts/retry-backports.sh against a fake gh.
+#
+# The fake answers the two pull request listings from WAITING and STALE and
+# records every dispatch, so each case checks exactly which backports the
+# script started, and that having nothing to retry is a success.
+#
+# Run from anywhere: bash .github/scripts/tests/retry-backports.test.sh
+set -uo pipefail
+
+HERE=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
+RETRY="$HERE/../retry-backports.sh"
+
+WORK=$(mktemp -d)
+trap 'rm -rf "$WORK"' EXIT
+mkdir "$WORK/bin"
+cat >"$WORK/bin/gh" <<'GH'
+#!/usr/bin/env bash
+case "$1 $2" in
+"pr list")
+	case " $* " in
+	*" --label backport-waiting "*) [ -z "$WAITING" ] || printf '%s\n' $WAITING ;;
+	*) [ -z "$STALE" ] || printf '%s\n' $STALE ;;
+	esac ;;
+"workflow run") echo "$*" >>"$DISPATCHED" ;;
+*) echo "unexpected: gh $*" >&2; exit 2 ;;
+esac
+GH
+chmod +x "$WORK/bin/gh"
+export PATH="$WORK/bin:$PATH" GITHUB_REPOSITORY=edera-dev/linux DISPATCHED="$WORK/dispatched"
+
+failures=0
+ok() { echo "ok   $1"; }
+bad() {
+	echo "FAIL $1" >&2
+	[ -z "${2:-}" ] || printf '     %s\n' "${2//$'\n'/$'\n'     }" >&2
+	failures=$((failures + 1))
+}
+
+# check <name> <args> <waiting> <stale> <expected pr numbers, space separated>
+check() {
+	local name=$1 args=$2 out got
+	: >"$DISPATCHED"
+	# shellcheck disable=SC2086 # $args is zero or one word
+	if ! out=$(WAITING=$3 STALE=$4 bash "$RETRY" $args 2>&1); then
+		bad "$name" "exited non-zero: $out"
+		return
+	fi
+	got=$(sed -E 's/.*backport_pr=([0-9]+).*/\1/' "$DISPATCHED" | xargs)
+	if [ "$got" = "$5" ]; then ok "$name"; else bad "$name" "dispatched '$got', expected '$5'"; fi
+}
+
+check "nothing waiting, no --stale" "" "" "" ""
+check "nothing waiting, nothing stale" --stale "" "" ""
+check "waiting pull requests are dispatched" "" "7 12" "" "7 12"
+check "stale backports are dispatched by number" --stale "" \
+	"backport/edera-6.18-lts/pr-23 backport/edera-6.18-lts/pr-9" "9 23"
+check "stale backports are ignored without --stale" "" "" "backport/edera-6.18-lts/pr-23" ""
+check "a pull request both waiting and stale goes once" --stale "23" \
+	"backport/edera-6.18-lts/pr-23" "23"
+
+if [ "$failures" -ne 0 ]; then
+	echo "$failures failure(s)" >&2
+	exit 1
+fi
+echo "all passed"
diff --git a/.github/workflows/automation-selftest.yml b/.github/workflows/automation-selftest.yml
index fff5f1f7ac104d..0f5b41444b775e 100644
--- a/.github/workflows/automation-selftest.yml
+++ b/.github/workflows/automation-selftest.yml
@@ -64,5 +64,8 @@ jobs:
       - name: Backport tests
         run: bash .github/scripts/tests/backport.test.sh
 
+      - name: Backport retry tests
+        run: bash .github/scripts/tests/retry-backports.test.sh
+
       - name: Shellcheck
         run: shellcheck .github/scripts/*.sh .github/scripts/tests/*.sh