Assertion failure in "dune exec -w" with package management enabled

[liate7]

In the most recent dune developer preview build, dune exec -w … raises an assertion failure.

Expected Behavior

Run the program, then restart/run the program on a change to the dependencies

Actual Behavior

Prints the following stack trace, then exits 1.

File "src/dune_engine/build_system.ml", line 67, characters 11-17:
File "src/dune_engine/build_system.ml", line 67, characters 11-17: Assertion
failed
Raised at Dune_engine__Build_system.State.update_build_progress_exn in file
  "src/dune_engine/build_system.ml" (inlined), line 67, characters 11-23
Called from Dune_engine__Build_system.State.start_rule_exn in file
  "src/dune_engine/build_system.ml" (inlined), line 76, characters 4-122
Called from Dune_engine__Build_system.Exported.execute_rule_impl in file
  "src/dune_engine/build_system.ml", line 462, characters 41-66
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", lFile "src/dune_engine/build_system.ml", line 67, characters 11-17:
File "src/dune_engine/build_system.ml", line 67, characters 11-17: Assertion
failed
Raised at Dune_engine__Build_system.State.update_build_progress_exn in file
  "src/dune_engine/build_system.ml" (inlined), line 67, characters 11-23
Called from Dune_engine__Build_system.State.start_rule_exn in file
  "src/dune_engine/build_system.ml" (inlined), line 76, characters 4-122
Called from Dune_engine__Build_system.Exported.execute_rule_impl in file
  "src/dune_engine/build_system.ml", line 462, characters 41-66
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11
Re-raised at Stdune__Exn.raise_with_backtrace in file
  "otherlibs/stdune/src/exn.ml" (inlined), line 38, characters 27-56
Called from Stdune__Exn_with_backtrace.reraise in file
  "otherlibs/stdune/src/exn_with_backtrace.ml", line 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11

I must not crash.  Uncertainty is the mind-killer. Exceptions are the
little-death that brings total obliteration.  I will fully express my cases. 
Execution will pass over me and through me.  And when it has gone past, I
will unwind the stack along its path.  Where the cases are handled there will
be nothing.  Only I will remain.
ine 20, characters 33-71
Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
  line 76, characters 8-11

I must not crash.  Uncertainty is the mind-killer. Exceptions are the
little-death that brings total obliteration.  I will fully express my cases. 
Execution will pass over me and through me.  And when it has gone past, I
will unwind the stack along its path.  Where the cases are handled there will
be nothing.  Only I will remain.

Reproduction

Run

dune init project test
cd test
dune pkg lock
dune exec --watch test

Specifications

• Version of dune (output of dune --version): "Dune Developer Preview: build 2024-09-26T01:30:16+00:00, git revision 17071ec30d10390badcb6cb1f6a43984b1be54a6"
• Operating system (distribution and version): Linux 6.10.7, Guix System

Additional information

The error happens before it actually resolves the exec target; I accidentally tried dune exec --watch bin/test.exe when testing the minimal repro and it still raised that failure.

• Link to gist with verbose output (run dune with the --verbose flag): output of dune exec --watch --verbose test