pulp does not work on COIN_CMD

[zxt5]

I want to use pulp with COIN_CMD, but it does not work. For reference, PULP_CBC_CMD works fine, and cbc also works correctly from command line. Here is an example:

from pulp import *

solver = COIN_CMD()
# solver = PULP_CBC_CMD() # works fine
file_path = "seed.mps"

vars, prob = LpProblem.fromMPS(file_path)
prob.solve(solver)

status = LpStatus.get(prob.status)
print(f"Status: {status}")

output:

Welcome to the CBC MILP Solver
Version: Devel (unstable)
Build Date: Apr  7 2025
command line - /tmp/86b414af1de948e5bac2808cfcb3937b-pulp.mps -timeMode elapsed -branch -printingOptions all -solution /tmp/86b414af1de948e5bac2808cfcb3937b-pulp.sol (default strategy 1)
At line 2 NAME          MODEL
At line 3 ROWS
At line 23 COLUMNS
At line 202 RHS
At line 221 BOUNDS
At line 240 ENDATA
Problem MODEL has 18 rows, 9 columns and 162 elements
Coin0008I MODEL read with 0 errors
Option for timeMode changed from cpu to elapsed
Total time (CPU seconds):       0.000299   (Wallclock seconds):       0.000605106
Status: Undefined

Was I using pulp wrong? Any suggestion is appreciated.

[zxt5]

I guess this is because the newest cbc need an explicit cmd option -solve to solve the problem

[pchtsp]

Try reproducing this behavior via the command line (without pulp) and see if you make it work. If you do, open an issue in the cbc github: https://github.com/coin-or/cbc