From 0a3eb22360bdb5e948ef8e7cb8f41958c541b54b Mon Sep 17 00:00:00 2001
From: Yaroslav Bolyukin <iam@lach.pw>
Date: Sat, 19 Jul 2025 23:52:32 +0200
Subject: [PATCH] fix: wait on incomplete assignment in REPL

Fixes: https://github.com/NixOS/nix/issues/13507
---
 src/libcmd/repl.cc | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/src/libcmd/repl.cc b/src/libcmd/repl.cc
index 5c6dd7ffb..38d06336b 100644
--- a/src/libcmd/repl.cc
+++ b/src/libcmd/repl.cc
@@ -869,14 +869,8 @@ void NixRepl::addVarToScope(const Symbol name, Value & v)
 
 Expr * NixRepl::parseString(std::string s)
 {
-    return state->parseExprFromString(std::move(s), state->rootPath("."), staticEnv);
-}
-
-void NixRepl::evalString(std::string s, Value & v)
-{
-    Expr * e;
     try {
-        e = parseString(s);
+        return state->parseExprFromString(std::move(s), state->rootPath("."), staticEnv);
     } catch (ParseError & e) {
         if (e.msg().find("unexpected end of file") != std::string::npos)
             // For parse errors on incomplete input, we continue waiting for the next line of
@@ -885,6 +879,11 @@ void NixRepl::evalString(std::string s, Value & v)
         else
             throw;
     }
+}
+
+void NixRepl::evalString(std::string s, Value & v)
+{
+    Expr * e = parseString(s);
     e->eval(*state, *env, v);
     state->forceValue(v, v.determinePos(noPos));
 }