lean4-htt/tests/lean/run/trace.lean
Sebastian Ullrich f47dfe9e7f
perf: Options.hasTrace (#12001)
Drastically speeds up `isTracingEnabledFor` in the common case, which
has evolved from "no options set" to "`Elab.async` and probably some
linter options set but no `trace`".

## Breaking changes

`Lean.Options` is now an opaque type. The basic but not all of the
`KVMap` API has been redefined on top of it.
2026-01-16 09:03:40 +00:00

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2.1 KiB
Text

import Lean.CoreM
open Lean
structure MyState where
(trace_state : TraceState := {})
(s : Nat := 0)
abbrev M := CoreM
def tst1 : M Unit :=
do trace[module] (m!"hello" ++ MessageData.nest 9 (m!"\n" ++ "world"));
trace[module.aux] "another message";
pure ()
def tst2 (b : Bool) : M Unit :=
withTraceNode `module (fun _ => return "message") do
tst1;
trace[bughunt] "at test2";
if b then throwError "error";
tst1;
pure ()
partial def ack : Nat → Nat → Nat
| 0, n => n+1
| m+1, 0 => ack m 1
| m+1, n+1 => ack m (ack (m+1) n)
def slow (b : Bool) : Nat :=
ack 4 (cond b 0 1)
def tst3 (b : Bool) : M Unit :=
do withTraceNode `module.slow (fun _ => return m!"slow: {slow b}") do {
tst2 b;
tst1
};
trace[bughunt] "at end of tst3";
-- Messages are computed lazily. The following message will only be computed
-- if `trace.slow is active.
trace[slow] (m!"slow message: " ++ toString (slow b))
-- This is true even if it is a monad computation:
trace[slow] (m!"slow message: " ++ (← pure (toString (slow b))))
def run (x : M Unit) : M Unit :=
withReader
(fun ctx =>
-- Try commenting/uncommeting the following `setBool`s
let opts := ctx.options;
let opts := opts.set `trace.module true;
-- let opts := opts.set `trace.module.aux false;
let opts := opts.set `trace.bughunt true;
-- let opts := opts.set `trace.slow true;
{ ctx with options := opts })
(tryCatch (tryFinally x printTraces) (fun _ => IO.println "ERROR"))
/--
info: [module] message
[module] hello
world
[bughunt] at test2
ERROR
---
trace: [module] message
[module] hello
world
[bughunt] at test2
-/
#guard_msgs in
#eval run (tst3 true)
/--
info: [module] message
[module] hello
world
[bughunt] at test2
[module] hello
world
[module] hello
world
[bughunt] at end of tst3
---
trace: [module] message
[module] hello
world
[bughunt] at test2
[module] hello
world
[module] hello
world
[bughunt] at end of tst3
-/
#guard_msgs in
#eval run (tst3 false)