diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc index 5e2f71649..86251adf7 100644 --- a/src/libexpr/eval.cc +++ b/src/libexpr/eval.cc @@ -1665,7 +1665,8 @@ void EvalState::callFunction(Value & fun, size_t nrArgs, Value * * args, Value & try { fn->fun(*this, vCur.determinePos(noPos), args, vCur); } catch (Error & e) { - addErrorTrace(e, pos, "while calling the '%1%' builtin", fn->name); + if (fn->addTrace) + addErrorTrace(e, pos, "while calling the '%1%' builtin", fn->name); throw; } @@ -1713,7 +1714,8 @@ void EvalState::callFunction(Value & fun, size_t nrArgs, Value * * args, Value & // so the debugger allows to inspect the wrong parameters passed to the builtin. fn->fun(*this, vCur.determinePos(noPos), vArgs, vCur); } catch (Error & e) { - addErrorTrace(e, pos, "while calling the '%1%' builtin", fn->name); + if (fn->addTrace) + addErrorTrace(e, pos, "while calling the '%1%' builtin", fn->name); throw; } diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh index f15d19653..f45971290 100644 --- a/src/libexpr/eval.hh +++ b/src/libexpr/eval.hh @@ -69,6 +69,13 @@ struct PrimOp */ const char * doc = nullptr; + /** + * Add a trace item, `while calling the '' builtin` + * + * This is used to remove the redundant item for `builtins.addErrorContext`. + */ + bool addTrace = true; + /** * Implementation of the primop. */ diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index 84f24de5a..729271828 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -826,7 +826,7 @@ static void prim_addErrorContext(EvalState & state, const PosIdx pos, Value * * auto message = state.coerceToString(pos, *args[0], context, "while evaluating the error message passed to builtins.addErrorContext", false, false).toOwned(); - e.addTrace(nullptr, HintFmt(message)); + e.addTrace(nullptr, HintFmt(message), TracePrint::Always); throw; } } @@ -834,6 +834,8 @@ static void prim_addErrorContext(EvalState & state, const PosIdx pos, Value * * static RegisterPrimOp primop_addErrorContext(PrimOp { .name = "__addErrorContext", .arity = 2, + // The normal trace item is redundant + .addTrace = false, .fun = prim_addErrorContext, }); diff --git a/src/libutil/error.cc b/src/libutil/error.cc index d1e864a1a..036e19e26 100644 --- a/src/libutil/error.cc +++ b/src/libutil/error.cc @@ -11,9 +11,9 @@ namespace nix { -void BaseError::addTrace(std::shared_ptr && e, HintFmt hint) +void BaseError::addTrace(std::shared_ptr && e, HintFmt hint, TracePrint print) { - err.traces.push_front(Trace { .pos = std::move(e), .hint = hint }); + err.traces.push_front(Trace { .pos = std::move(e), .hint = hint, .print = print }); } void throwExceptionSelfCheck(){ @@ -163,7 +163,7 @@ static bool printPosMaybe(std::ostream & oss, std::string_view indent, const std return hasPos; } -void printTrace( +static void printTrace( std::ostream & output, const std::string_view & indent, size_t & count, @@ -379,29 +379,39 @@ std::ostream & showErrorInfo(std::ostream & out, const ErrorInfo & einfo, bool s // A consecutive sequence of stack traces that are all in `tracesSeen`. std::vector skippedTraces; size_t count = 0; + bool truncate = false; for (const auto & trace : einfo.traces) { if (trace.hint.str().empty()) continue; if (!showTrace && count > 3) { - oss << "\n" << ANSI_WARNING "(stack trace truncated; use '--show-trace' to show the full trace)" ANSI_NORMAL << "\n"; - break; + truncate = true; } - if (tracesSeen.count(trace)) { - skippedTraces.push_back(trace); - continue; + if (!truncate || trace.print == TracePrint::Always) { + + if (tracesSeen.count(trace)) { + skippedTraces.push_back(trace); + continue; + } + + tracesSeen.insert(trace); + + printSkippedTracesMaybe(oss, ellipsisIndent, count, skippedTraces, tracesSeen); + + count++; + + printTrace(oss, ellipsisIndent, count, trace); } - tracesSeen.insert(trace); - - printSkippedTracesMaybe(oss, ellipsisIndent, count, skippedTraces, tracesSeen); - - count++; - - printTrace(oss, ellipsisIndent, count, trace); } + printSkippedTracesMaybe(oss, ellipsisIndent, count, skippedTraces, tracesSeen); + + if (truncate) { + oss << "\n" << ANSI_WARNING "(stack trace truncated; use '--show-trace' to show the full, detailed trace)" ANSI_NORMAL << "\n"; + } + oss << "\n" << prefix; } diff --git a/src/libutil/error.hh b/src/libutil/error.hh index 89f5ad021..d23625a54 100644 --- a/src/libutil/error.hh +++ b/src/libutil/error.hh @@ -61,9 +61,22 @@ void printCodeLines(std::ostream & out, const Pos & errPos, const LinesOfCode & loc); +/** + * When a stack frame is printed. + */ +enum struct TracePrint { + /** + * The default behavior; always printed when `--show-trace` is set. + */ + Default, + /** Always printed. Produced by `builtins.addErrorContext`. */ + Always, +}; + struct Trace { std::shared_ptr pos; HintFmt hint; + TracePrint print = TracePrint::Default; }; inline bool operator<(const Trace& lhs, const Trace& rhs); @@ -161,7 +174,7 @@ public: addTrace(std::move(e), HintFmt(std::string(fs), args...)); } - void addTrace(std::shared_ptr && e, HintFmt hint); + void addTrace(std::shared_ptr && e, HintFmt hint, TracePrint print = TracePrint::Default); bool hasTrace() const { return !err.traces.empty(); } diff --git a/tests/functional/lang.sh b/tests/functional/lang.sh index 12df32c87..e35795a7a 100755 --- a/tests/functional/lang.sh +++ b/tests/functional/lang.sh @@ -68,8 +68,16 @@ done for i in lang/eval-fail-*.nix; do echo "evaluating $i (should fail)"; i=$(basename "$i" .nix) + flags="$( + if [[ -e "lang/$i.flags" ]]; then + sed -e 's/#.*//' < "lang/$i.flags" + else + # note that show-trace is also set by init.sh + echo "--eval --strict --show-trace" + fi + )" if - expectStderr 1 nix-instantiate --eval --strict --show-trace "lang/$i.nix" \ + expectStderr 1 nix-instantiate $flags "lang/$i.nix" \ | sed "s!$(pwd)!/pwd!g" > "lang/$i.err" then diffAndAccept "$i" err err.exp diff --git a/tests/functional/lang/eval-fail-addErrorContext-example.err.exp b/tests/functional/lang/eval-fail-addErrorContext-example.err.exp new file mode 100644 index 000000000..4fad8f5c8 --- /dev/null +++ b/tests/functional/lang/eval-fail-addErrorContext-example.err.exp @@ -0,0 +1,24 @@ +error: + … while counting down; n = 10 + + … while counting down; n = 9 + + … while counting down; n = 8 + + … while counting down; n = 7 + + … while counting down; n = 6 + + … while counting down; n = 5 + + … while counting down; n = 4 + + … while counting down; n = 3 + + … while counting down; n = 2 + + … while counting down; n = 1 + + (stack trace truncated; use '--show-trace' to show the full, detailed trace) + + error: kaboom diff --git a/tests/functional/lang/eval-fail-addErrorContext-example.flags b/tests/functional/lang/eval-fail-addErrorContext-example.flags new file mode 100644 index 000000000..9b1f6458f --- /dev/null +++ b/tests/functional/lang/eval-fail-addErrorContext-example.flags @@ -0,0 +1 @@ +--eval --strict --no-show-trace diff --git a/tests/functional/lang/eval-fail-addErrorContext-example.nix b/tests/functional/lang/eval-fail-addErrorContext-example.nix new file mode 100644 index 000000000..996b24688 --- /dev/null +++ b/tests/functional/lang/eval-fail-addErrorContext-example.nix @@ -0,0 +1,9 @@ +let + countDown = n: + if n == 0 + then throw "kaboom" + else + builtins.addErrorContext + "while counting down; n = ${toString n}" + ("x" + countDown (n - 1)); +in countDown 10