Memory not released after getting last algorithm from history in Python

[Martyn Gigg]

This was first noticed on SANS when running the add files section of the ISIS SANS scripts.

The following script will reproduce the problem:

def foo():
    wsName= 'AddFilesSumTempory'
    filename = "SANS2D00028546.nxs"
    outWs = Load(Filename=filename,OutputWorkspace=wsName)
    props = outWs.getHistory().lastAlgorithm()
    LoadEventNexus(Filename=filename, OutputWorkspace='AddFilesSumTempory', LoadMonitors=True)
    
    DeleteWorkspace('AddFilesSumTempory')
    DeleteWorkspace('AddFilesSumTempory_monitors')
    
for i in range(1):
    foo()

After execution you should see that no workspaces are left but checking the memory usage of the MantidPlot executable still shows a sizeable amount of memory being used. Note that this should be a generic problem and not limited to SANS files.

If you run "Clear All Memory" then the memory is returned as expected.

[Martyn Gigg]

Use an unmanaged algorithm when creating from a string

There is no reason the algorithm should be retained in the manager. Refs #11589

Changeset: 495144416e5046e4e119e29f0cc0655ad83d6bf0

[Martyn Gigg]

This is being verified as ​pull request #614.

[Martyn Gigg]

Fix expected error string

The message is now just what comes out for the factory Refs #11589

Changeset: 8ca545a5464c05ba37050a076f0ab2406e6c4acb

[Martyn Gigg]

Fix crash in SANS reduction.

Python doesn't seem to guarantee that the shared_ptr will survive during a chained method call. This is poor coding practice anyway... Refs #11589

Changeset: 66908103bf092fc1a0ed28ef0a5355721aa8ee99

[NickDraper]

Merge pull request #614 from mantidproject/11589_memory_lost_on_get_history

Fix memory "leak" when retrieving history from Python

Full changeset: ​4434327bc022acf95e2228affcb6d7be7507f8da

[Nick Draper]

Somehow these slipped through without a resolution. Set to Fixed.

[Stuart Campbell]

This ticket has been transferred to github issue ​12427