From f058567e9af9be999cfc0d52188931c8134f0f93 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Wed, 9 Apr 2025 00:15:08 +0200
Subject: [PATCH] Fix printAmbiguous() / printValueAsJSON()

---
 .../include/nix/expr/print-ambiguous.hh       |  8 +++----
 src/libexpr/print-ambiguous.cc                | 24 +++++++++++--------
 src/libexpr/value-to-json.cc                  |  4 +++-
 src/nix-env/user-env.cc                       |  2 +-
 src/nix-instantiate/nix-instantiate.cc        |  7 ++++--
 5 files changed, 27 insertions(+), 18 deletions(-)

diff --git a/src/libexpr/include/nix/expr/print-ambiguous.hh b/src/libexpr/include/nix/expr/print-ambiguous.hh
index 09a849c49..1dafd5d56 100644
--- a/src/libexpr/include/nix/expr/print-ambiguous.hh
+++ b/src/libexpr/include/nix/expr/print-ambiguous.hh
@@ -15,10 +15,10 @@ namespace nix {
  * See: https://github.com/NixOS/nix/issues/9730
  */
 void printAmbiguous(
-    Value &v,
-    const SymbolTable &symbols,
-    std::ostream &str,
-    std::set<const void *> *seen,
+    EvalState & state,
+    Value & v,
+    std::ostream & str,
+    std::set<const void *> * seen,
     int depth);
 
 }
diff --git a/src/libexpr/print-ambiguous.cc b/src/libexpr/print-ambiguous.cc
index 0646783c2..e5bfe3ccd 100644
--- a/src/libexpr/print-ambiguous.cc
+++ b/src/libexpr/print-ambiguous.cc
@@ -7,10 +7,10 @@ namespace nix {
 
 // See: https://github.com/NixOS/nix/issues/9730
 void printAmbiguous(
-    Value &v,
-    const SymbolTable &symbols,
-    std::ostream &str,
-    std::set<const void *> *seen,
+    EvalState & state,
+    Value & v,
+    std::ostream & str,
+    std::set<const void *> * seen,
     int depth)
 {
     checkInterrupt();
@@ -26,9 +26,13 @@ void printAmbiguous(
     case nBool:
         printLiteralBool(str, v.boolean());
         break;
-    case nString:
-        printLiteralString(str, v.string_view());
+    case nString: {
+        NixStringContext context;
+        copyContext(v, context);
+        // FIXME: make devirtualization configurable?
+        printLiteralString(str, state.devirtualize(v.string_view(), context));
         break;
+    }
     case nPath:
         str << v.path().to_string(); // !!! escaping?
         break;
@@ -40,9 +44,9 @@ void printAmbiguous(
             str << "«repeated»";
         else {
             str << "{ ";
-            for (auto & i : v.attrs()->lexicographicOrder(symbols)) {
-                str << symbols[i->name] << " = ";
-                printAmbiguous(*i->value, symbols, str, seen, depth - 1);
+            for (auto & i : v.attrs()->lexicographicOrder(state.symbols)) {
+                str << state.symbols[i->name] << " = ";
+                printAmbiguous(state, *i->value, str, seen, depth - 1);
                 str << "; ";
             }
             str << "}";
@@ -56,7 +60,7 @@ void printAmbiguous(
             str << "[ ";
             for (auto v2 : v.listItems()) {
                 if (v2)
-                    printAmbiguous(*v2, symbols, str, seen, depth - 1);
+                    printAmbiguous(state, *v2, str, seen, depth - 1);
                 else
                     str << "(nullptr)";
                 str << " ";
diff --git a/src/libexpr/value-to-json.cc b/src/libexpr/value-to-json.cc
index 51652db1f..6230fa585 100644
--- a/src/libexpr/value-to-json.cc
+++ b/src/libexpr/value-to-json.cc
@@ -31,7 +31,9 @@ json printValueAsJSON(EvalState & state, bool strict,
 
         case nString:
             copyContext(v, context);
-            out = v.c_str();
+            // FIXME: only use the context from `v`.
+            // FIXME: make devirtualization configurable?
+            out = state.devirtualize(v.c_str(), context);
             break;
 
         case nPath:
diff --git a/src/nix-env/user-env.cc b/src/nix-env/user-env.cc
index e149b6aeb..c49f2885d 100644
--- a/src/nix-env/user-env.cc
+++ b/src/nix-env/user-env.cc
@@ -110,7 +110,7 @@ bool createUserEnv(EvalState & state, PackageInfos & elems,
        environment. */
     auto manifestFile = ({
         std::ostringstream str;
-        printAmbiguous(manifest, state.symbols, str, nullptr, std::numeric_limits<int>::max());
+        printAmbiguous(state, manifest, str, nullptr, std::numeric_limits<int>::max());
         StringSource source { toView(str) };
         state.store->addToStoreFromDump(
             source, "env-manifest.nix", FileSerialisationMethod::Flat, ContentAddressMethod::Raw::Text, HashAlgorithm::SHA256, references);
diff --git a/src/nix-instantiate/nix-instantiate.cc b/src/nix-instantiate/nix-instantiate.cc
index c1b6cc66a..4ae82b2bf 100644
--- a/src/nix-instantiate/nix-instantiate.cc
+++ b/src/nix-instantiate/nix-instantiate.cc
@@ -52,7 +52,10 @@ void processExpr(EvalState & state, const Strings & attrPaths,
             else
                 state.autoCallFunction(autoArgs, v, vRes);
             if (output == okRaw)
-                std::cout << *state.coerceToString(noPos, vRes, context, "while generating the nix-instantiate output");
+                std::cout <<
+                    state.devirtualize(
+                        *state.coerceToString(noPos, vRes, context, "while generating the nix-instantiate output"),
+                        context);
                 // We intentionally don't output a newline here. The default PS1 for Bash in NixOS starts with a newline
                 // and other interactive shells like Zsh are smart enough to print a missing newline before the prompt.
             else if (output == okXML)
@@ -63,7 +66,7 @@ void processExpr(EvalState & state, const Strings & attrPaths,
             } else {
                 if (strict) state.forceValueDeep(vRes);
                 std::set<const void *> seen;
-                printAmbiguous(vRes, state.symbols, std::cout, &seen, std::numeric_limits<int>::max());
+                printAmbiguous(state, vRes, std::cout, &seen, std::numeric_limits<int>::max());
                 std::cout << std::endl;
             }
         } else {