"write" methods don't work after `redirectOutput()`

[mattmilten]

After calling redirectOutput(), e.g. writeProblem() does not produce a file but prints the problem description to the outstream.

Apparently, we redirect everything to the new messagehandler.

[fserra]

interseting my search didn't tell me about this

[CGraczyk]

I assume this is still relevant so i will leave this open.

[Joao-Dionisio]

Is this still relevant, @mattmilten @fserra?

[camold]

Still not solved. Here is a minimal example:

import pyscipopt
m = pyscipopt.Model("test")
m.redirectOutput()
m.optimize()
# writes out the usual log files
m.writeProblem("test.mps")
# writes the model description (in mps format) to the python console but not to file
# test.mps is created but is empty

PySCIPOpt 4.3.0
SCIPOptSuite-8.0.4-Linux

[LuizSuzana]

A possible related issue happens when calling setLogfile and writeProblem. The problem description is written to a file (argument of writeProblem), and also to the logfile. I would expect it to not be included in the logfile.

import pyscipopt
m = pyscipopt.Model("test2")
x = m.addVar("x", vtype="B")
m.addCons(x >= 1, name="C1")
m.setLogfile('file.log')
m.optimize()
m.writeProblem("test.lp")
# file.log is created with the output from the solver, but it also contains the problem description in the lp format
# test.lp is correctly created with the problem description in the lp format

[DominikKamp]

I guess relayMessage() in scip.pxi should still write to file if it is not stdout and in this case the same as in logMessage should happen (otherwise file == NULL was translated into file == stdout in messagePrintInfo() before calling this function and only then it should be written to the console).