From c51b527c280ee08b3ce3ca6d229139c4292b3176 Mon Sep 17 00:00:00 2001
From: Ben Burdette <bburdette@gmail.com>
Date: Fri, 7 Jan 2022 16:37:44 -0700
Subject: [PATCH] add env to DebugTrace

---
 src/libcmd/repl.cc  | 1 +
 src/libexpr/eval.cc | 9 ++++++---
 src/libexpr/eval.hh | 6 +++++-
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/libcmd/repl.cc b/src/libcmd/repl.cc
index 57463bd79..fdd63621f 100644
--- a/src/libcmd/repl.cc
+++ b/src/libcmd/repl.cc
@@ -927,6 +927,7 @@ void runRepl(
           DebugTrace 
                 {.pos = debugError->info().errPos,
                  .expr = expr,
+                 .env = *repl->env,
                  .hint = debugError->info().msg
                 });
 
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 585042b9d..e01147169 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -913,7 +913,7 @@ LocalNoInline(void addErrorTrace(Error & e, const Pos & pos, const char * s, con
 }
 
 LocalNoInline(std::unique_ptr<DebugTraceStacker>
-  makeDebugTraceStacker(EvalState &state, Expr &expr, std::optional<ErrPos> pos, const char * s, const string & s2))
+  makeDebugTraceStacker(EvalState &state, Expr &expr, Env &env, std::optional<ErrPos> pos, const char * s, const string & s2))
 {
   return std::unique_ptr<DebugTraceStacker>(
       new DebugTraceStacker(
@@ -921,6 +921,7 @@ LocalNoInline(std::unique_ptr<DebugTraceStacker>
           DebugTrace 
                 {.pos = pos,
                  .expr = expr,
+                 .env = env,
                  .hint = hintfmt(s, s2)
                 }));
 }
@@ -1161,6 +1162,7 @@ void EvalState::cacheFile(
                 makeDebugTraceStacker(
                     *this,
                     *e,
+                    this->baseEnv,
                     (e->getPos() ? std::optional(ErrPos(*e->getPos())) : std::nullopt),
                     "while evaluating the file '%1%':", resolvedPath)
                 : nullptr;
@@ -1394,6 +1396,7 @@ void ExprSelect::eval(EvalState & state, Env & env, Value & v)
               makeDebugTraceStacker(
                   state,
                   *this,
+                  env,
                   *pos2,
                   "while evaluating the attribute '%1%'",
                   showAttrPath(state, env, attrPath))
@@ -1543,7 +1546,7 @@ void EvalState::callFunction(Value & fun, size_t nrArgs, Value * * args, Value &
             try {
                 auto dts =
                     debuggerHook ?
-                        makeDebugTraceStacker(*this, *lambda.body, lambda.pos,
+                        makeDebugTraceStacker(*this, *lambda.body, env2, lambda.pos,
                                            "while evaluating %s",
                                            (lambda.name.set()
                                                ? "'" + (string) lambda.name + "'"
@@ -1948,7 +1951,7 @@ void EvalState::forceValueDeep(Value & v)
                       debuggerHook ?
                           // if the value is a thunk, we're evaling.  otherwise no trace necessary.
                           (i.value->isThunk() ? 
-                              makeDebugTraceStacker(*this, *v.thunk.expr, *i.pos,
+                              makeDebugTraceStacker(*this, *v.thunk.expr, *v.thunk.env, *i.pos,
                                                 "while evaluating the attribute '%1%'", i.name)
                               : nullptr)
                       : nullptr;
diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index 5dbb9b5e5..3c74bb4a1 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -77,6 +77,7 @@ std::shared_ptr<RegexCache> makeRegexCache();
 struct DebugTrace {
     std::optional<ErrPos> pos;
     const Expr &expr;
+    const Env &env;
     hintformat hint;
 };
 
@@ -203,7 +204,7 @@ public:
        trivial (i.e. doesn't require arbitrary computation). */
     void evalFile(const Path & path, Value & v, bool mustBeTrivial = false);
 
-    /* Like `cacheFile`, but with an already parsed expression. */
+    /* Like `evalFile`, but with an already parsed expression. */
     void cacheFile(
         const Path & path,
         const Path & resolvedPath,
@@ -416,6 +417,9 @@ class DebugTraceStacker {
         DebugTraceStacker(EvalState &evalState, DebugTrace t)
         :evalState(evalState), trace(t)
         {
+         
+            // evalState.debuggerHook(const Error & error, const Env & env, const Expr & expr);
+
             evalState.debugTraces.push_front(t);
         }
         ~DebugTraceStacker()