Potential leak memory

rgb

run prog, show in activity program
cache memory used by program 106Mo
click in button
create in loop 1 million of window

For i As Integer = 0 To 1000000

#create 1 million Of Window!!

Var w As New Window

Next

eat 1,6Go Memory and continue (I kill the program for doesn't crash the Mac 🙂 )

don't sure if normal comportement or leak memory

leakmemory.objo

2kB

Garry

Thanks for reporting this and for providing the example project. This was a genuine bug.

When an unshown Window went out of scope, Objo released the language-level object but did not close the underlying native window. Repeating this caused native windows (and therefore memory) to accumulate.

This has now been fixed. Discarded windows automatically release their native resources, so explicitly calling Close() should not be necessary.

I retested your original project on macOS. Previously it exceeded 2.4 GB and continued climbing. With the fix, it ran for 47 minutes at roughly 237 MB, with only the main window and occasionally the window currently being constructed remaining in memory.

I also checked for a deeper object-retention problem. Tests confirm that the Objo object, its window state, and the Avalonia window all become collectible after finalisation.

The fix will be included in the next release: https://feedback.objo.dev/bug/933

Thanks again. This was an excellent catch.

madamov

I think this is second time I see in examples that declaration of the variable is used in a loop. Is there a reason for it like new declaration is also definition clearing previous instance of variable?

Garry

Good question.

Local variables declared inside a loop are block-scoped in Objo. Each iteration creates a new w, and its reference is released when that iteration ends. It is not the following declaration that clears the previous value - the previous variable has already gone out of scope.

You could instead declare w before the loop and assign a new window each iteration. In that case, each assignment releases the previous value, although the final value remains referenced until the surrounding scope ends.

The declaration inside the loop was therefore valid and was not the cause of this bug. Objo’s ARC was correctly releasing each language-level Window; the problem was that its underlying native window was not also being closed. That native cleanup is what has now been fixed.