memory leak for uncompressed .trx files.

[skoudoro]

TrxFile.close() seems to silently skips mmap cleanup for uncompressed .trx files.

I catched that when working on dipy/dipy#3808

here is a basic example

  import tempfile                                                                                                                                              
  import os                                                                                                                                                    
  import numpy as np                                                                                                                                           
  import trx.trx_file_memmap as tmm                                                                                                                            
                  
  trx = tmm.TrxFile(nb_streamlines=2, nb_vertices=6)
  trx.streamlines._data[:] = np.random.rand(6, 3).astype(np.float32)
  trx.streamlines._offsets[:] = np.array([0, 3], dtype=np.uint32)
  trx.streamlines._lengths[:] = np.array([3, 3], dtype=np.uint32)

  with tempfile.TemporaryDirectory() as tmp:
      trx_path = os.path.join(tmp, "test.trx")
      tmm.save(trx, trx_path)
      trx.close()

      loaded = tmm.load(trx_path)
      print("_uncompressed_folder_handle:", loaded._uncompressed_folder_handle)
      # we have None here  <-- bug: should be a TemporaryDirectory handle

      # close() silently skips ALL mmap cleanup.
      loaded.close()

      print("streamlines._data type:", type(loaded.streamlines._data))
      # After close(), _data should be gone — but close() only called __init__()
      # without first releasing the np.memmap handles. 
      # so on windows, file is locked, on linux, mmap is never released so leak

I will dig a bit more to see if it was on purpose and there is something that I am doing wrong.

feedback are welcome @frheault and @arokem

[frheault]

That's an embarassing oversight ! Thank you for identifying and fixing it !