diff options
| -rw-r--r-- | src/libexpr/eval.hh | 3 | ||||
| -rw-r--r-- | src/libexpr/primops.cc | 21 | ||||
| -rw-r--r-- | tests/lang.sh | 2 |
3 files changed, 26 insertions, 0 deletions
diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh index 4eaa3c9b0..7db954bf4 100644 --- a/src/libexpr/eval.hh +++ b/src/libexpr/eval.hh @@ -646,6 +646,9 @@ struct EvalSettings : Config Setting<bool> useEvalCache{this, true, "eval-cache", "Whether to use the flake evaluation cache."}; + + Setting<bool> traceVerbose{this, false, "trace-verbose", + "Whether `builtins.traceVerbose` should trace its first argument when evaluated."}; }; extern EvalSettings evalSettings; diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index eea274301..ac84e26c3 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -970,6 +970,15 @@ static RegisterPrimOp primop_trace({ }); +/* Takes two arguments and evaluates to the second one. Used as the + * builtins.traceVerbose implementation when --trace-verbose is not enabled + */ +static void prim_second(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceValue(*args[1], pos); + v = *args[1]; +} + /************************************************************* * Derivations *************************************************************/ @@ -3926,6 +3935,18 @@ void EvalState::createBaseEnv() addPrimOp("__exec", 1, prim_exec); } + addPrimOp({ + .fun = evalSettings.traceVerbose ? prim_trace : prim_second, + .arity = 2, + .name = symbols.create("__traceVerbose"), + .args = { "e1", "e2" }, + .doc = R"( + Evaluate *e1* and print its abstract syntax representation on standard + error if `--trace-verbose` is enabled. Then return *e2*. This function + is useful for debugging. + )", + }); + /* Add a value containing the current Nix expression search path. */ mkList(v, searchPath.size()); int n = 0; diff --git a/tests/lang.sh b/tests/lang.sh index f09eaeb31..c0b0fc58c 100644 --- a/tests/lang.sh +++ b/tests/lang.sh @@ -5,6 +5,8 @@ export NIX_REMOTE=dummy:// nix-instantiate --eval -E 'builtins.trace "Hello" 123' 2>&1 | grep -q Hello nix-instantiate --eval -E 'builtins.addErrorContext "Hello" 123' 2>&1 +nix-instantiate --trace-verbose --eval -E 'builtins.traceVerbose "Hello" 123' 2>&1 | grep -q Hello +(! nix-instantiate --eval -E 'builtins.traceVerbose "Hello" 123' 2>&1 | grep -q Hello) (! nix-instantiate --show-trace --eval -E 'builtins.addErrorContext "Hello" 123' 2>&1 | grep -q Hello) nix-instantiate --show-trace --eval -E 'builtins.addErrorContext "Hello" (throw "Foo")' 2>&1 | grep -q Hello |