fix(podman): mount managed /etc/hosts for all custom services

internal/podman/quadlet_embed_test.go

@@ -404,8 +404,19 @@ func TestGenerateCustomQuadlet_NoShareHosts(t *testing.T) {
 		Image: "docker.io/library/mongo:7",
 	}
 	out := GenerateCustomQuadlet(svc)
-	if strings.Contains(out, "/etc/hosts") {
-		t.Errorf("should not mount hosts file when ShareHosts=false, got:\n%s", out)
+	// Even without ShareHosts, a sidecar service must mount lerd's managed
+	// /etc/hosts. Otherwise podman falls back to base_hosts_file (the host's
+	// /etc/hosts by default), where a stale or client-shim "127.0.0.1 lerd-<svc>"
+	// entry shadows the container-DNS name and breaks connections — e.g.
+	// lerd-phpmyadmin resolving lerd-mysql to its own loopback (#issue).
+	wantVolume := "Volume=" + config.ContainerHostsFile() + ":/etc/hosts:ro,z"
+	if !strings.Contains(out, wantVolume) {
+		t.Errorf("ShareHosts=false must mount the managed container hosts file to override host inheritance, got:\n%s", out)
+	}
+	// The browser-testing hosts variant is reserved for ShareHosts=true.
+	browserVolume := "Volume=" + config.BrowserHostsFile() + ":/etc/hosts:ro,z"
+	if strings.Contains(out, browserVolume) {
+		t.Errorf("ShareHosts=false must not mount the browser hosts file, got:\n%s", out)
 	}
 }
 

internal/podman/quadlet_generate.go

@@ -50,8 +50,20 @@ func GenerateCustomQuadlet(svc *config.CustomService) string {
 		b.WriteString("PodmanArgs=--init\n")
 	}
 
+	// Always mount a lerd-managed /etc/hosts. Without an explicit mount podman
+	// synthesises the file from base_hosts_file, which defaults to the host's
+	// own /etc/hosts — so any "127.0.0.1 lerd-<svc>" entry there (a stale line
+	// from an older lerd, or one written for a client shim / host-proxy app)
+	// shadows the container-DNS name and the service resolves to its own
+	// loopback instead of the peer container, e.g. lerd-phpmyadmin failing to
+	// reach lerd-mysql with "Connection refused". PHP-FPM containers already
+	// bind-mount this file; sidecar services (phpmyadmin, pgadmin, mongo-express)
+	// need it too. ShareHosts services additionally want .test domains resolved
+	// to nginx, so they get the browser-hosts variant.
 	if svc.ShareHosts {
 		fmt.Fprintf(&b, "Volume=%s:/etc/hosts:ro,z\n", config.BrowserHostsFile())
+	} else {
+		fmt.Fprintf(&b, "Volume=%s:/etc/hosts:ro,z\n", config.ContainerHostsFile())
 	}
 
 	for _, port := range svc.Ports {