From 1c55544a428c61448dcaa4b431f20bde52c3991e Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Sat, 1 Apr 2023 22:05:06 +0200
Subject: eval: Fix crash on missing printValue tBlackhole case

Fixes #8119
---
 src/libexpr/eval.cc | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to 'src')

diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 584bbc879..22337a3ff 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -173,7 +173,17 @@ void Value::print(const SymbolTable & symbols, std::ostream & str,
     case tFloat:
         str << fpoint;
         break;
+    case tBlackhole:
+        // Although we know for sure that it's going to be an infinite recursion
+        // when this value is accessed _in the current context_, it's likely
+        // that the user will misinterpret a simpler «infinite recursion» output
+        // as a definitive statement about the value, while in fact it may be
+        // a valid value after `builtins.trace` and perhaps some other steps
+        // have completed.
+        str << "«potential infinite recursion»";
+        break;
     default:
+        printError("Nix evaluator internal error: Value::print(): invalid value type %1%", internalType);
         abort();
     }
 }
-- 
cgit v1.2.3