Hard timeout abort

Currently, Cozy will hang at the following state for a long time:

$ time cozy examples/select-flatmap.ds -t 10
Checking call legality...
Checking invariant preservation...
Done!
Adding query q...
STARTING IMPROVEMENT JOB q
updating with 1 new solutions
update order:
  --> q
considering update 1/1...
SOLUTION FOR q AT 0:00:00.037117 [size=74]
----------------------------------------
  _var131 : Bag<{ A : Int, B : String }> = Rs
  _var132 : Bag<{ B : String, C : Int }> = Ss
  _var133 : Bag<{ B : String, C : Int }> = Qs
  _var134 : Bag<{ B : String, C : Int }> = Ws
  return FlatMap {r -> FlatMap {s -> FlatMap {q -> Map {w -> ((r).A, (s).C, (q).B, (w).C)} (Filter {w -> (((q).B == (w).B) and ((r).A == 15))} (_var134))} (_var133)} (_var132)} (_var131)
----------------------------------------
Stopping jobs
requesting stop for ImproveQueryJob[q]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Waiting on 1 jobs...
  --> ImproveQueryJob[q] [pid=26128]
Stopping SafeQueue...
Done!
Generating IR...
Inlining calls...
Generating code for extension types...
Concretization functions:

_var79 : Bag<{ A : Int, B : String }> = Rs
_var80 : Bag<{ B : String, C : Int }> = Ss
_var81 : Bag<{ B : String, C : Int }> = Qs
_var82 : Bag<{ B : String, C : Int }> = Ws

SelectFlatmap:
  type R = { A : Int, B : String }
  type S = { B : String, C : Int }
  type Q = { B : String, C : Int }
  type W = { B : String, C : Int }
  state _var79 : Bag<{ A : Int, B : String }>
  state _var80 : Bag<{ B : String, C : Int }>
  state _var81 : Bag<{ B : String, C : Int }>
  state _var82 : Bag<{ B : String, C : Int }>

  query q():
    FlatMap {r -> FlatMap {s -> FlatMap {q -> Map {w -> ((r).A, (s).C, (q).B, (w).C)} (Filter {w -> (((q).B == (w).B) and ((r).A == 15))} (_var82))} (_var81)} (_var80)} (_var79)

Number of improvements done: 1
cozy examples/select-flatmap.ds -t 10  51.85s user 0.34s system 99% cpu 52.625 total

I guess Cozy is waiting for Z3 to return – but this might far exceed the specified timeout (10s).

We should be able to let Cozy give up early, kill the Z3 job and output immediately after timeout.

NOTE: some hints on the semantic of timeout https://github.com/CozySynthesizer/cozy/issues/52

[punndcoder28]

OK. If I run into any problems I will leave a comment here. Thanks.

[Calvin-L]

In the original example, it appears the job is actually busy converting the syntax tree into a Z3 query, so additionally:

• The solver should check the stop flag periodically while converting ASTs to Z3 queries.

(And perhaps we should look into optimizing encoding bag equality a little…)