From 65e142d19317d26f99ad1a9ec91a7aabdf119ef8 Mon Sep 17 00:00:00 2001
From: Johannes Kirschbauer <hsjobeki@gmail.com>
Date: Fri, 6 Jun 2025 12:02:44 +0200
Subject: [PATCH] primops/import: add preflight check to parseExprFromFile

---
 src/libexpr/eval.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index eacbf4c9b..70d6bf00f 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -3055,6 +3055,8 @@ Expr * EvalState::parseExprFromFile(const SourcePath & path)
 Expr * EvalState::parseExprFromFile(const SourcePath & path, std::shared_ptr<StaticEnv> & staticEnv)
 {
     auto buffer = path.resolveSymlinks().readFile();
+
+    if (buffer.size() == 0) throw Error("cannot import empty file '%s'", path);
     // readFile hopefully have left some extra space for terminators
     buffer.append("\0\0", 2);
     return parse(buffer.data(), buffer.size(), Pos::Origin(path), path.parent(), staticEnv);