1	import Base
2	import ./Console.bend as Console
3	
4	# Pure checkpoint policy. Console.get_env maps an unset value to "", so the
5	# non-empty guard distinguishes disabled injection from an exact empty match.
6	def nonempty(value: String) -> Bool:
7	  match value:
8	    case SNil{}: False{}
9	    case SCon{_, _}: True{}
10	
11	def enabled(+configured: String, requested: String) -> Bool:
12	  Bool.and(nonempty(configured), String.eq(configured, requested))
13	
14	# Irreducible host boundary: emit an unbuffered marker and stop this process.
15	def stop(name: String) -> IO(Result<&1, &1, U32 & String, Unit>):
16	  import "./effs/crash_point.c"
17	  import "./effs/crash_point.js"
18	
19	def hit_decision(active: Bool, name: String) -> IO(Result<&1, &1, U32 & String, Unit>):
20	  match active:
21	    case True{}:
22	      stop(name)
23	    case False{}:
24	      IO.pure(Result<&1, &1, U32 & String, Unit>, Done{Unit{}})
25	
26	# Test-only checkpoint. Environment lookup and activation policy stay in Bend;
27	# only marker emission and SIGSTOP remain in the host twins.
28	def hit(+name: String) -> IO(Result<&1, &1, U32 & String, Unit>):
29	  do IO<Result<&1, &1, U32 & String, Unit>>:
30	    configured : String <- IO.try(String, Console.get_env("MYLSM_CRASH_POINT"))
31	    hit_decision(enabled(configured, name), name)