From fece0bbef9dc72b35bf7e0749b7d512854c066d1 Mon Sep 17 00:00:00 2001
From: Kinvert <keith@kinvert.com>
Date: Mon, 17 Aug 2026 17:09:51 -0400
Subject: [PATCH] Fix seethestars segfault on empty dataset

---
 src/constellation.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/constellation.c b/src/constellation.c
index 9520da0f05..7661ba6ae5 100644
--- a/src/constellation.c
+++ b/src/constellation.c
@@ -1096,6 +1096,10 @@ Dataset load_dataset(const char* path) {
     }
     free(line);
     fclose(fp);
+    if (data.n == 0) {
+        fprintf(stderr, "no data in %s -- run ./cache_data after training\n", path);
+        exit(1);
+    }
     return data;
 }