From 2d4c9d8f4a41520e53441985b1fce5be87b731c8 Mon Sep 17 00:00:00 2001 From: Robert Hensing Date: Tue, 23 Apr 2024 01:21:50 +0200 Subject: [PATCH] Add builtins.warn --- src/libexpr/eval-settings.cc | 4 ++++ src/libexpr/eval-settings.hh | 34 +++++++++++++++++++++++++++++---- src/libexpr/primops.cc | 37 ++++++++++++++++++++++++++++++++++++ tests/functional/lang.sh | 7 +++++++ 4 files changed, 78 insertions(+), 4 deletions(-) diff --git a/src/libexpr/eval-settings.cc b/src/libexpr/eval-settings.cc index 2ccbe327f..85b1677ea 100644 --- a/src/libexpr/eval-settings.cc +++ b/src/libexpr/eval-settings.cc @@ -48,6 +48,10 @@ EvalSettings::EvalSettings() { auto var = getEnv("NIX_PATH"); if (var) nixPath = parseNixPath(*var); + + var = getEnv("NIX_ABORT_ON_WARN"); + if (var && (var == "1" || var == "yes" || var == "true")) + builtinsAbortOnWarn = true; } Strings EvalSettings::getDefaultNixPath() diff --git a/src/libexpr/eval-settings.hh b/src/libexpr/eval-settings.hh index dbfc3b2c7..f1fb539bd 100644 --- a/src/libexpr/eval-settings.hh +++ b/src/libexpr/eval-settings.hh @@ -158,13 +158,39 @@ struct EvalSettings : Config Setting builtinsTraceDebugger{this, false, "debugger-on-trace", R"( - If set to true and the `--debugger` flag is given, - [`builtins.trace`](@docroot@/language/builtins.md#builtins-trace) will - enter the debugger like - [`builtins.break`](@docroot@/language/builtins.md#builtins-break). + If set to true and the `--debugger` flag is given, the following functions + will enter the debugger like [`builtins.break`](@docroot@/language/builtins.md#builtins-break). + + * [`builtins.trace`](@docroot@/language/builtins.md#builtins-trace) + * [`builtins.traceVerbose`](@docroot@/language/builtins.md#builtins-traceVerbose) + if [`trace-verbose`](#conf-trace-verbose) is set to true. + * [`builtins.warn`](@docroot@/language/builtins.md#builtins-warn) This is useful for debugging warnings in third-party Nix code. )"}; + + Setting builtinsDebuggerOnWarn{this, false, "debugger-on-warn", + R"( + If set to true and the `--debugger` flag is given, [`builtins.warn`](@docroot@/language/builtins.md#builtins-warn) + will enter the debugger like [`builtins.break`](@docroot@/language/builtins.md#builtins-break). + + This is useful for debugging warnings in third-party Nix code. + + Use [`debugger-on-trace`](#conf-debugger-on-trace) to also enter the debugger on legacy warnings that are logged with [`builtins.trace`](@docroot@/language/builtins.md#builtins-trace). + )"}; + + Setting builtinsAbortOnWarn{this, false, "abort-on-warn", + R"( + If set to true, [`builtins.warn`](@docroot@/language/builtins.md#builtins-warn) will throw an error when logging a warning. + + This will give you a stack trace that leads to the location of the warning. + + This is useful for finding information about warnings in third-party Nix code when you can not start the interactive debugger, such as when Nix is called from a non-interactive script. See [`debugger-on-warn`](#conf-debugger-on-warn). + + Currently, a stack trace can only be produced when the debugger is enabled, or when evaluation is aborted. + + This option can be enabled by setting `NIX_ABORT_ON_WARN=1` in the environment. + )"}; }; extern EvalSettings evalSettings; diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index 7371bd488..9319709c1 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -1043,6 +1043,43 @@ static RegisterPrimOp primop_trace({ .fun = prim_trace, }); +static void prim_warn(EvalState & state, const PosIdx pos, Value * * args, Value & v) +{ + state.forceValue(*args[0], pos); + if (args[0]->type() == nString) + printMsg(lvlWarn, ANSI_WARNING "warning:" ANSI_NORMAL " %1%", args[0]->string_view()); + else + printMsg(lvlWarn, ANSI_WARNING "warning:" ANSI_NORMAL " %1%", ValuePrinter(state, *args[0])); + + if (evalSettings.builtinsAbortOnWarn) { + state.error("aborting to reveal stack trace of warning, as abort-on-warn is set").debugThrow(); + } + if ((evalSettings.builtinsTraceDebugger || evalSettings.builtinsDebuggerOnWarn) && state.debugRepl && !state.debugTraces.empty()) { + const DebugTrace & last = state.debugTraces.front(); + state.runDebugRepl(nullptr, last.env, last.expr); + } + state.forceValue(*args[1], pos); + v = *args[1]; +} + +static RegisterPrimOp primop_warn({ + .name = "__warn", + .args = {"e1", "e2"}, + .doc = R"( + Evaluate *e1*, which must be a string and print iton standard error as a warning. + Then return *e2*. + This function is useful for non-critical situations where attention is advisable. + + If the + [`debugger-on-trace`](@docroot@/command-ref/conf-file.md#conf-debugger-on-trace) + or [`debugger-on-warn`](@docroot@/command-ref/conf-file.md#conf-debugger-on-warn) + option is set to `true` and the `--debugger` flag is given, the + interactive debugger will be started when `warn` is called (like + [`break`](@docroot@/language/builtins.md#builtins-break)). + )", + .fun = prim_warn, +}); + /* Takes two arguments and evaluates to the second one. Used as the * builtins.traceVerbose implementation when --trace-verbose is not enabled diff --git a/tests/functional/lang.sh b/tests/functional/lang.sh index a853cfd81..843ff7cfa 100755 --- a/tests/functional/lang.sh +++ b/tests/functional/lang.sh @@ -36,6 +36,13 @@ nix-instantiate --eval -E 'let x = builtins.trace { x = x; } true; in x' \ nix-instantiate --eval -E 'let x = { repeating = x; tracing = builtins.trace x true; }; in x.tracing'\ 2>&1 | grepQuiet -F 'trace: { repeating = «repeated»; tracing = «potential infinite recursion»; }' +nix-instantiate --eval -E 'builtins.warn "Hello" 123' 2>&1 | grepQuiet 'warning: Hello' +nix-instantiate --eval -E 'builtins.addErrorContext "while doing ${"something"} interesting" (builtins.warn "Hello" 123)' 2>/dev/null | grepQuiet 123 +nix-instantiate --eval -E 'let x = builtins.warn { x = x; } true; in x' \ + 2>&1 | grepQuiet -E 'warning: { x = «potential infinite recursion»; }' +expectStderr 1 nix-instantiate --eval --abort-on-warn -E 'builtins.warn "Hello" 123' | grepQuiet Hello +NIX_ABORT_ON_WARN=1 expectStderr 1 nix-instantiate --eval -E 'builtins.addErrorContext "while doing ${"something"} interesting" (builtins.warn "Hello" 123)' | grepQuiet "while doing something interesting" + set +x badDiff=0