ci: keep the cache probe running past an expected failure (#234)

The runner starts `shell: bash` steps as `bash -e -o pipefail`, so run 453
stopped at the first TIMEOUT instead of probing the other addresses. Each
probe now swallows its own exit code, and the env listing and the forge
lookup no longer abort the step when they come back empty.

Refs #234

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.forgejo/workflows/diag-cache-probe.yml

@@ -16,6 +16,9 @@ name: Diag — cache server reachability (#234)
 #
 # Steps that use bash features set `shell: bash`: inside a container the runner
 # defaults to `sh`, and a job-level `defaults` block is refused by the runner.
+# The runner starts those steps as `bash -e -o pipefail`, so every probe that
+# is expected to fail must swallow its own exit code (run 453 stopped at the
+# first TIMEOUT for that reason).
 
 on:
   pull_request:
@@ -35,8 +38,8 @@ jobs:
         shell: bash
         run: |
           echo "Runner-provided variables (names only):"
-          compgen -e | grep -E 'ACTIONS|RUNNER|FORGEJO|GITEA' | sort | sed 's/^/  /'
-          compgen -e | grep -E '_RUNNER_VERSION$' | while read -r v; do echo "  $v=${!v}"; done
+          compgen -e | grep -E 'ACTIONS|RUNNER|FORGEJO|GITEA' | sort | sed 's/^/  /' || true
+          compgen -e | grep -E '_RUNNER_VERSION$' | while read -r v; do echo "  $v=${!v}"; done || true
 
           url="${ACTIONS_CACHE_URL:-}"
           if [ -z "$url" ]; then
@@ -58,7 +61,7 @@ jobs:
           case "$host" in *:*) shown="[$host]" ;; esac
           echo
           echo "Cache address advertised by the runner: $scheme://$shown:$port/<path redacted>"
-          forge=$(getent ahostsv4 git.lacompagniemaximus.com | awk '{ print $1; exit }')
+          forge=$(getent ahostsv4 git.lacompagniemaximus.com | awk '{ print $1; exit }') || true
           echo "git.lacompagniemaximus.com resolves to (IPv4): ${forge:-unresolved}"
           echo "Container addresses: $(hostname -I 2>/dev/null || echo unknown)"
           gw_hex=$(awk '$2 == "00000000" { print $3; exit }' /proc/net/route)
@@ -71,8 +74,7 @@ jobs:
           probe() {
             local label=$1 h=$2 p=$3 start ms rc err verdict
             start=$(date +%s%N)
-            err=$(timeout 10 bash -c "exec 3<>/dev/tcp/$h/$p" 2>&1)
-            rc=$?
+            err=$(timeout 10 bash -c "exec 3<>/dev/tcp/$h/$p" 2>&1) && rc=0 || rc=$?
             ms=$(( ($(date +%s%N) - start) / 1000000 ))
             case $rc in
               0)   verdict="OPEN" ;;
@@ -114,7 +116,7 @@ jobs:
           key="diag-234-$(date -u +%Y%m%dT%H%M%SZ)-$RANDOM"
           mkdir -p probe-payload
           printf '%s' "$key" > probe-payload/stamp
-          echo "key=$key" >> "$GITHUB_OUTPUT"
+          echo "key=$key" >> "${GITHUB_OUTPUT:-$FORGEJO_OUTPUT}"
           echo "payload key: $key"
 
       - name: Save it (actions/cache/save)