quadlet kube: consider empty pod as running

Since commit 945aade38b we do tear down the kube units if all pods
failed to start. This however broke the use case of an empty pod as we
did not consider that being starting successfully which is wrong and
caused a regression for at least one user.

To fix this special case the empty pod and consider that running.

Fixes: #25786
Fixes: 945aade38b ("quadlet kube: correctly mark unit as failed")

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

pkg/domain/infra/abi/play.go

@@ -287,8 +287,16 @@ func (ic *ContainerEngine) PlayKube(ctx context.Context, body io.Reader, options
 	setRanContainers := func(r *entities.PlayKubeReport) {
 		if !ranContainers {
 			for _, p := range r.Pods {
+				numCons := len(p.Containers) + len(p.InitContainers)
+				if numCons == 0 {
+					// special case, the pod has no containers (besides infra)
+					// That seems to be valid per https://github.com/containers/podman/issues/25786
+					// and users could depend on it so mark it as running in that case.
+					ranContainers = true
+					break
+				}
 				// If the list of container errors is less then the total number of pod containers then we know it did start.
-				if len(p.ContainerErrors) < len(p.Containers)+len(p.InitContainers) {
+				if len(p.ContainerErrors) < numCons {
 					ranContainers = true
 					break
 				}

test/system/252-quadlet.bats

@@ -1160,6 +1160,35 @@ EOF
     kill "$nc_pid"
 }
 
+# https://github.com/containers/podman/issues/25786
+@test "quadlet kube - pod without containers" {
+    local port=$(random_free_port)
+    # Create the YAML file
+    pod_name="p-$(safename)"
+    yaml_source="$PODMAN_TMPDIR/no_cons_$(safename).yaml"
+    cat >$yaml_source <<EOF
+apiVersion: v1
+kind: Pod
+metadata:
+  name: $pod_name
+EOF
+
+    # Create the Quadlet file
+    local quadlet_file=$PODMAN_TMPDIR/no_cons_$(safename).kube
+    cat > $quadlet_file <<EOF
+[Kube]
+Yaml=${yaml_source}
+EOF
+
+    run_quadlet "$quadlet_file"
+    service_setup $QUADLET_SERVICE_NAME
+
+    run_podman pod ps --format "{{.Name}}--{{.Status}}"
+    assert "$output" =~ "$pod_name--Running" "pod is running"
+
+    service_cleanup $QUADLET_SERVICE_NAME inactive
+}
+
 @test "quadlet - image files" {
     local quadlet_tmpdir=$PODMAN_TMPDIR/quadlets