DebugStackTracker class in one place

src/libcmd/command.cc

@@ -75,6 +75,8 @@ ref<EvalState> EvalCommand::getEvalState()
 
                 printStaticEnvBindings(expr);
 
+                std::cout << evalState->vCallFlake << std::endl;
+
                 std::cout << "expr: " << std::endl;
                 expr.show(std::cout);
                 std::cout << std::endl;

src/libcmd/repl.cc

@@ -451,6 +451,7 @@ bool NixRepl::processLine(string line)
         }
         else if (arg == "error") {
           if (this->debugError.has_value()) {
+            // TODO user --show-trace setting?
             showErrorInfo(std::cout, (*debugError)->info(), true);
           }
           else

src/libexpr/eval.cc

@@ -17,6 +17,7 @@
 #include <sys/resource.h>
 #include <iostream>
 #include <fstream>
+#include <functional>
 
 #include <sys/resource.h>
 
@@ -854,13 +855,20 @@ LocalNoInlineNoReturn(void throwAssertionError(const Pos & pos, const char * s,
 
 LocalNoInlineNoReturn(void throwUndefinedVarError(const Pos & pos, const char * s, const string & s1, Env & env, Expr *expr))
 {
+    std::cout << "throwUndefinedVarError" << std::endl;
+
+    std::cout << "loggerSettings.showTrace: " << loggerSettings.showTrace << std::endl;
+
     auto error = UndefinedVarError({
         .msg = hintfmt(s, s1),
         .errPos = pos
     });
 
-    if (debuggerHook && expr)
+    if (debuggerHook && expr) {
+    
+         std::cout << "throwUndefinedVarError debuggerHook" << std::endl;
         debuggerHook(error, env, *expr);
+    }
 
     throw error;
 }
@@ -888,6 +896,16 @@ 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(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)
 {
     v.mkString(dupString(s));
@@ -934,7 +952,7 @@ inline Value * EvalState::lookupVar(Env * env, const ExprVar & var, bool noEval)
             return j->value;
         }
         if (!env->prevWith) {
-            throwUndefinedVarError(var.pos, "undefined variable '%1%'", var.name, *env, 0);
+            throwUndefinedVarError(var.pos, "undefined variable '%1%'", var.name, *env, (Expr*)&var);
         }
         for (size_t l = env->prevWith; l; --l, env = env->up) ;
     }
@@ -1092,6 +1110,39 @@ void EvalState::resetFileCache()
     fileParseCache.clear();
 }
 
+class DebugTraceStacker {
+  public:
+   DebugTraceStacker(EvalState &evalState, Trace t)
+    :evalState(evalState), trace(t)
+    {
+        evalState.debugTraces.push_front(t);
+    }
+   ~DebugTraceStacker() {
+     // assert(evalState.debugTraces.front() == trace);
+     evalState.debugTraces.pop_front();
+   }
+   
+   EvalState &evalState;
+   Trace trace;
+                         
+};
+
+// 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;
+
+// };
+
+
 
 void EvalState::cacheFile(
     const Path & path,
@@ -1103,6 +1154,15 @@ 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>();
+
+          // 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 &&
@@ -1472,6 +1532,7 @@ void EvalState::callFunction(Value & fun, size_t nrArgs, Value * * args, Value &
             try {
                 lambda.body->eval(*this, env2, vCur);
             } catch (Error & e) {
+                std::cout << "eval showErrorInfo showTrace: " << loggerSettings.showTrace.get() << std::endl;
                 if (loggerSettings.showTrace.get()) {
                     addErrorTrace(e, lambda.pos, "while evaluating %s",
                         (lambda.name.set()

src/libexpr/eval.hh

@@ -109,6 +109,8 @@ public:
     RootValue vCallFlake = nullptr;
     RootValue vImportedDrvToDerivation = nullptr;
 
+    std::list<Trace> debugTraces;
+
 private:
     SrcToStore srcToStore;
 

src/libexpr/nixexpr.hh

@@ -84,6 +84,7 @@ struct Expr
     virtual void setName(Symbol & name);
 
     std::shared_ptr<const StaticEnv> staticenv;
+    virtual Pos* getPos() = 0;
 };
 
 std::ostream & operator << (std::ostream & str, const Expr & e);
@@ -100,6 +101,8 @@ struct ExprInt : Expr
     ExprInt(NixInt n) : n(n) { mkInt(v, n); };
     COMMON_METHODS
     Value * maybeThunk(EvalState & state, Env & env);
+
+    Pos* getPos() { return 0; }
 };
 
 struct ExprFloat : Expr
@@ -109,6 +112,8 @@ struct ExprFloat : Expr
     ExprFloat(NixFloat nf) : nf(nf) { mkFloat(v, nf); };
     COMMON_METHODS
     Value * maybeThunk(EvalState & state, Env & env);
+
+    Pos* getPos() { return 0; }
 };
 
 struct ExprString : Expr
@@ -118,6 +123,8 @@ struct ExprString : Expr
     ExprString(const Symbol & s) : s(s) { mkString(v, s); };
     COMMON_METHODS
     Value * maybeThunk(EvalState & state, Env & env);
+
+    Pos* getPos() { return 0; }
 };
 
 /* Temporary class used during parsing of indented strings. */
@@ -125,6 +132,8 @@ struct ExprIndStr : Expr
 {
     string s;
     ExprIndStr(const string & s) : s(s) { };
+
+    Pos* getPos() { return 0; }
 };
 
 struct ExprPath : Expr
@@ -134,6 +143,7 @@ struct ExprPath : Expr
     ExprPath(const string & s) : s(s) { v.mkPath(this->s.c_str()); };
     COMMON_METHODS
     Value * maybeThunk(EvalState & state, Env & env);
+    Pos* getPos() { return 0; }
 };
 
 typedef uint32_t Level;
@@ -161,6 +171,7 @@ struct ExprVar : Expr
     ExprVar(const Pos & pos, const Symbol & name) : pos(pos), name(name) { };
     COMMON_METHODS
     Value * maybeThunk(EvalState & state, Env & env);
+    Pos* getPos() { return &pos; }
 };
 
 struct ExprSelect : Expr
@@ -171,6 +182,7 @@ struct ExprSelect : Expr
     ExprSelect(const Pos & pos, Expr * e, const AttrPath & attrPath, Expr * def) : pos(pos), e(e), def(def), attrPath(attrPath) { };
     ExprSelect(const Pos & pos, Expr * e, const Symbol & name) : pos(pos), e(e), def(0) { attrPath.push_back(AttrName(name)); };
     COMMON_METHODS
+    Pos* getPos() { return &pos; }
 };
 
 struct ExprOpHasAttr : Expr
@@ -179,6 +191,7 @@ struct ExprOpHasAttr : Expr
     AttrPath attrPath;
     ExprOpHasAttr(Expr * e, const AttrPath & attrPath) : e(e), attrPath(attrPath) { };
     COMMON_METHODS
+    Pos* getPos() { return e->getPos(); }
 };
 
 struct ExprAttrs : Expr
@@ -207,6 +220,7 @@ struct ExprAttrs : Expr
     ExprAttrs(const Pos &pos) : recursive(false), pos(pos) { };
     ExprAttrs() : recursive(false), pos(noPos) { };
     COMMON_METHODS
+    Pos* getPos() { return &pos; }
 };
 
 struct ExprList : Expr
@@ -214,6 +228,7 @@ struct ExprList : Expr
     std::vector<Expr *> elems;
     ExprList() { };
     COMMON_METHODS
+    Pos* getPos() { return 0; }
 };
 
 struct Formal
@@ -252,6 +267,7 @@ struct ExprLambda : Expr
     string showNamePos() const;
     inline bool hasFormals() const { return formals != nullptr; }
     COMMON_METHODS
+    Pos* getPos() { return &pos; }
 };
 
 struct ExprCall : Expr
@@ -263,6 +279,7 @@ struct ExprCall : Expr
         : fun(fun), args(args), pos(pos)
     { }
     COMMON_METHODS
+    Pos* getPos() { return &pos; }
 };
 
 struct ExprLet : Expr
@@ -271,6 +288,7 @@ struct ExprLet : Expr
     Expr * body;
     ExprLet(ExprAttrs * attrs, Expr * body) : attrs(attrs), body(body) { };
     COMMON_METHODS
+    Pos* getPos() { return 0; }
 };
 
 struct ExprWith : Expr
@@ -280,6 +298,7 @@ struct ExprWith : Expr
     size_t prevWith;
     ExprWith(const Pos & pos, Expr * attrs, Expr * body) : pos(pos), attrs(attrs), body(body) { };
     COMMON_METHODS
+    Pos* getPos() { return &pos; }
 };
 
 struct ExprIf : Expr
@@ -288,6 +307,7 @@ struct ExprIf : Expr
     Expr * cond, * then, * else_;
     ExprIf(const Pos & pos, Expr * cond, Expr * then, Expr * else_) : pos(pos), cond(cond), then(then), else_(else_) { };
     COMMON_METHODS
+    Pos* getPos() { return &pos; }
 };
 
 struct ExprAssert : Expr
@@ -296,6 +316,7 @@ struct ExprAssert : Expr
     Expr * cond, * body;
     ExprAssert(const Pos & pos, Expr * cond, Expr * body) : pos(pos), cond(cond), body(body) { };
     COMMON_METHODS
+    Pos* getPos() { return &pos; }
 };
 
 struct ExprOpNot : Expr
@@ -303,6 +324,7 @@ struct ExprOpNot : Expr
     Expr * e;
     ExprOpNot(Expr * e) : e(e) { };
     COMMON_METHODS
+    Pos* getPos() { return 0; }
 };
 
 #define MakeBinOp(name, s) \
@@ -321,6 +343,7 @@ struct ExprOpNot : Expr
             e1->bindVars(env); e2->bindVars(env); \
         } \
         void eval(EvalState & state, Env & env, Value & v); \
+        Pos* getPos() { return &pos; } \
     };
 
 MakeBinOp(ExprOpEq, "==")
@@ -339,6 +362,7 @@ struct ExprConcatStrings : Expr
     ExprConcatStrings(const Pos & pos, bool forceString, vector<Expr *> * es)
         : pos(pos), forceString(forceString), es(es) { };
     COMMON_METHODS
+    Pos* getPos() { return &pos; }
 };
 
 struct ExprPos : Expr
@@ -346,6 +370,7 @@ struct ExprPos : Expr
     Pos pos;
     ExprPos(const Pos & pos) : pos(pos) { };
     COMMON_METHODS
+    Pos* getPos() { return &pos; }
 };
 
 

src/libutil/error.cc

@@ -221,6 +221,8 @@ static std::string indent(std::string_view indentFirst, std::string_view indentR
 
 std::ostream & showErrorInfo(std::ostream & out, const ErrorInfo & einfo, bool showTrace)
 {
+    std::cout << "showErrorInfo showTrace: " << showTrace << std::endl;
+  
     std::string prefix;
     switch (einfo.level) {
         case Verbosity::lvlError: {

src/libutil/logging.hh

@@ -38,6 +38,7 @@ typedef uint64_t ActivityId;
 struct LoggerSettings : Config
 {
     Setting<bool> showTrace{
+        // this, false, "show-trace",
         this, false, "show-trace",
         R"(
           Where Nix should print out a stack trace in case of Nix