From c263070d376d47012c57462f8d943109a34d3ae6 Mon Sep 17 00:00:00 2001
From: Rebecca Turner <rbt@sent.as>
Date: Mon, 3 Feb 2025 15:03:53 -0800
Subject: [PATCH] Fix crash in debugger mode using `with`

Fixes this crash (#592):

    $ nix repl --debugger
    Lix 2.92.0-dev-pre20241120-66f6dbd debugger
    Type :? for help.
    nix-repl> let x = 4; in __seq x (with x; (x: builtins.break x) 1)
    info: breakpoint reached

    [1]    949722 segmentation fault (core dumped)  nix repl --debugger

Change-Id: I13c72941dc325ff984dcce2a84c01c89b1c552af
---
 lix/libexpr/eval.cc                           |  4 ++--
 .../data/regression_l592.nix                  |  1 +
 .../data/regression_l592.test                 | 21 +++++++++++++++++++
 .../repl_characterization.cc                  |  1 +
 4 files changed, 25 insertions(+), 2 deletions(-)
 create mode 100644 tests/functional/repl_characterization/data/regression_l592.nix
 create mode 100644 tests/functional/repl_characterization/data/regression_l592.test

diff --git a/lix/libexpr/eval.cc b/lix/libexpr/eval.cc
index e2f3b8544..2e365f2b7 100644
--- a/lix/libexpr/eval.cc
+++ b/lix/libexpr/eval.cc
@@ -629,7 +629,7 @@ void printStaticEnvBindings(const SymbolTable & st, const StaticEnv & se)
 // just for the current level of Env, not the whole chain.
 void printWithBindings(const SymbolTable & st, const Env & env)
 {
-    if (!env.values[0]->isThunk()) {
+    if (env.values[0]->type() == nAttrs) {
         std::set<std::string_view> bindings;
         for (const auto & attr : *env.values[0]->attrs)
             bindings.emplace(st[attr.name]);
@@ -686,7 +686,7 @@ void mapStaticEnvBindings(const SymbolTable & st, const StaticEnv & se, const En
     if (env.up && se.up) {
         mapStaticEnvBindings(st, *se.up, *env.up, vm);
 
-        if (se.isWith && !env.values[0]->isThunk()) {
+        if (se.isWith && env.values[0]->type() == nAttrs) {
             // add 'with' bindings.
             Bindings::iterator j = env.values[0]->attrs->begin();
             while (j != env.values[0]->attrs->end()) {
diff --git a/tests/functional/repl_characterization/data/regression_l592.nix b/tests/functional/repl_characterization/data/regression_l592.nix
new file mode 100644
index 000000000..0962725b8
--- /dev/null
+++ b/tests/functional/repl_characterization/data/regression_l592.nix
@@ -0,0 +1 @@
+let x = 4; in __seq x (with x; (x: builtins.break x) 1)
diff --git a/tests/functional/repl_characterization/data/regression_l592.test b/tests/functional/repl_characterization/data/regression_l592.test
new file mode 100644
index 000000000..b0ba331ae
--- /dev/null
+++ b/tests/functional/repl_characterization/data/regression_l592.test
@@ -0,0 +1,21 @@
+@args --debugger
+
+  breakpoint reached
+
+  nix-repl> :quit
+  error:
+         … while evaluating the file '$TEST_DATA/regression_l592.nix':
+
+         … while calling the 'seq' builtin
+           at $TEST_DATA/regression_l592.nix:1:15:
+              1| let x = 4; in __seq x (with x; (x: builtins.break x) 1)
+               |               ^
+              2|
+
+         … while calling the 'break' builtin
+           at $TEST_DATA/regression_l592.nix:1:36:
+              1| let x = 4; in __seq x (with x; (x: builtins.break x) 1)
+               |                                    ^
+              2|
+
+         error: breakpoint reached
diff --git a/tests/functional/repl_characterization/repl_characterization.cc b/tests/functional/repl_characterization/repl_characterization.cc
index eccaeaf8e..8fde93c4a 100644
--- a/tests/functional/repl_characterization/repl_characterization.cc
+++ b/tests/functional/repl_characterization/repl_characterization.cc
@@ -177,6 +177,7 @@ REPL_TEST(no_nested_debuggers);
 REPL_TEST(regression_9917);
 REPL_TEST(regression_9918);
 REPL_TEST(regression_l145);
+REPL_TEST(regression_l592);
 REPL_TEST(repl_overlays);
 REPL_TEST(repl_overlays_compose);
 REPL_TEST(repl_overlays_destructure_without_dotdotdot_errors);