From deb1fd66e8c884937827813c079135532913ca86 Mon Sep 17 00:00:00 2001
From: Ben Burdette <bburdette@gmail.com>
Date: Thu, 23 Dec 2021 09:08:41 -0700
Subject: [PATCH] makeDebugTraceStacker

---
 src/libexpr/eval.cc | 93 +++++++++++++++------------------------------
 1 file changed, 31 insertions(+), 62 deletions(-)

diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 15eaef667..d7deb550e 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -49,10 +49,8 @@ class DebugTraceStacker {
      // assert(evalState.debugTraces.front() == trace);
      evalState.debugTraces.pop_front();
    }
-   
    EvalState &evalState;
    Trace trace;
-                         
 };
 
 static char * dupString(const char * s)
@@ -882,8 +880,7 @@ LocalNoInlineNoReturn(void throwUndefinedVarError(const Pos & pos, const char *
     });
 
     if (debuggerHook && expr) {
-    
-         std::cout << "throwUndefinedVarError debuggerHook" << std::endl;
+        std::cout << "throwUndefinedVarError debuggerHook" << std::endl;
         debuggerHook(error, env, *expr);
     }
 
@@ -913,15 +910,17 @@ LocalNoInline(void addErrorTrace(Error & e, const Pos & pos, const char * s, con
     e.addTrace(pos, s, s2);
 }
 
-// LocalNoInline(void makeErrorTrace(Error & e, const char * s, const string & s2))
-// {
-//     Trace { .pos = e, .hint = hint }
-// }
+LocalNoInline(std::unique_ptr<DebugTraceStacker>
+  makeDebugTraceStacker(EvalState &state, std::optional<ErrPos> pos, const char * s, const string & s2))
+{
+  return std::unique_ptr<DebugTraceStacker>(
+      new DebugTraceStacker(
+          state,
+          Trace {.pos = pos,
+                 .hint = hintfmt(s, s2)
+                }));
+}
 
-// LocalNoInline(void makeErrorTrace(Error & e, const Pos & pos, const char * s, const string & s2))
-// {
-//   return Trace { .pos = e, .hint = hintfmt(s, s2); };
-// }
 
 void mkString(Value & v, const char * s)
 {
@@ -1127,20 +1126,6 @@ void EvalState::resetFileCache()
     fileParseCache.clear();
 }
 
-// class DebugTraceStacker {
-//    DebugTraceStacker(std::ref<EvalState> evalState, std::ref<Trace> t)
-//     :evalState(evalState), trace(t)
-//     {
-//         evalState->debugTraces.push_front(t);
-//     }
-//    ~DebugTraceStacker() {
-//      assert(evalState->debugTraces.pop_front() == trace);
-//    }
-
-//    std::ref<EvalState> evalState;
-//    std::ref<Trace> trace;
-
-// };
 
 
 
@@ -1154,15 +1139,14 @@ void EvalState::cacheFile(
     fileParseCache[resolvedPath] = e;
 
     try {
-        std::unique_ptr<DebugTraceStacker> dts = debuggerHook ? 
-          std::unique_ptr<DebugTraceStacker>(new DebugTraceStacker(*this, 
-          Trace { .pos = (e->getPos() ? std::optional(ErrPos(*e->getPos())) : std::nullopt), 
-                  .hint = hintfmt("while evaluating the file '%1%':", resolvedPath)
-                }
-        )) : std::unique_ptr<DebugTraceStacker>();
+        std::unique_ptr<DebugTraceStacker> dts =
+            debuggerHook ?
+                makeDebugTraceStacker(
+                    *this,
+                    (e->getPos() ? std::optional(ErrPos(*e->getPos())) : std::nullopt),
+                    "while evaluating the file '%1%':", resolvedPath)
+                : std::unique_ptr<DebugTraceStacker>();
 
-          // Trace( .pos = (e->getPos() ? std::optional(ErrPos(*e->getPos())): 
-          // 		std::nullopt), hintfmt("while evaluating the file '%1%':", resolvedPath)); 
         // Enforce that 'flake.nix' is a direct attrset, not a
         // computation.
         if (mustBeTrivial &&
@@ -1387,16 +1371,13 @@ void ExprSelect::eval(EvalState & state, Env & env, Value & v)
     e->eval(state, env, vTmp);
 
     try {
-        std::unique_ptr<DebugTraceStacker> dts = 
-          debuggerHook ? 
-          std::unique_ptr<DebugTraceStacker>(
-              new DebugTraceStacker(
-                      state, 
-                      Trace { .pos = *pos2, 
-                              .hint = hintfmt(
-                                "while evaluating the attribute '%1%'",
-                                showAttrPath(state, env, attrPath))
-                            }))
+        std::unique_ptr<DebugTraceStacker> dts =
+          debuggerHook ?
+              makeDebugTraceStacker(
+                  state,
+                  *pos2,
+                  "while evaluating the attribute '%1%'",
+                  showAttrPath(state, env, attrPath))
           : std::unique_ptr<DebugTraceStacker>();
 
         for (auto & i : attrPath) {
@@ -1541,21 +1522,15 @@ void EvalState::callFunction(Value & fun, size_t nrArgs, Value * * args, Value &
 
             /* Evaluate the body. */
             try {
-                std::unique_ptr<DebugTraceStacker> dts = 
-                    debuggerHook ? 
-                        std::unique_ptr<DebugTraceStacker>(
-                            new DebugTraceStacker(
-                                *this,
-                                Trace {.pos = lambda.pos,
-                                       .hint = hintfmt(
+                std::unique_ptr<DebugTraceStacker> dts =
+                    debuggerHook ?
+                        makeDebugTraceStacker(*this, lambda.pos,
                                            "while evaluating %s",
                                            (lambda.name.set()
                                                ? "'" + (string) lambda.name + "'"
                                                : "anonymous lambda"))
-                                      }))
                         : std::unique_ptr<DebugTraceStacker>();
 
-              
                 lambda.body->eval(*this, env2, vCur);
             } catch (Error & e) {
                 std::cout << "eval showErrorInfo showTrace: " << loggerSettings.showTrace.get() << std::endl;
@@ -1950,18 +1925,12 @@ void EvalState::forceValueDeep(Value & v)
         if (v.type() == nAttrs) {
             for (auto & i : *v.attrs)
                 try {
-                    std::unique_ptr<DebugTraceStacker> dts = 
-                      debuggerHook ? 
-                      std::unique_ptr<DebugTraceStacker>(
-                          new DebugTraceStacker(
-                                  *this, 
-                                  Trace { .pos = *i.pos, 
-                                          .hint = hintfmt(
+                    std::unique_ptr<DebugTraceStacker> dts =
+                      debuggerHook ?
+                          makeDebugTraceStacker(*this, *i.pos,
                                             "while evaluating the attribute '%1%'", i.name)
-                                        }))
                       : std::unique_ptr<DebugTraceStacker>();
 
-                  
                     recurse(*i.value);
                 } catch (Error & e) {
                     addErrorTrace(e, *i.pos, "while evaluating the attribute '%1%'", i.name);