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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - Web Inspector: Heap Snapshot should be able to tell me if an object was collected"
href="https://bugs.webkit.org/show_bug.cgi?id=163151#c8">Comment # 8</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - Web Inspector: Heap Snapshot should be able to tell me if an object was collected"
href="https://bugs.webkit.org/show_bug.cgi?id=163151">bug 163151</a>
from <span class="vcard"><a class="email" href="mailto:sbarati@apple.com" title="Saam Barati <sbarati@apple.com>"> <span class="fn">Saam Barati</span></a>
</span></b>
<pre>(In reply to <a href="show_bug.cgi?id=163151#c6">comment #6</a>)
<span class="quote">> (In reply to <a href="show_bug.cgi?id=163151#c3">comment #3</a>)
> > One nice thing about the "alive + dead" display is that it allows you to see
> > memory usage go up and / or down between snapshots.
> >
> > Today, since old snapshots update when new snapshots are taken, they
> > retroactively edit their total memory usage numbers, erasing debugging
> > history.
>
> The Snapshot List view shows both the original Size and the Live Size. The
> original Size never changes. When viewing the live objects within the
> snapshot, the Retain Size percentages are based off of the original Size not
> the current Live Size.
>
>
> (In reply to <a href="show_bug.cgi?id=163151#c5">comment #5</a>)
> > My perfect debugging scenario for what I was trying to do would go like this:
> > 1. Take a snapshot
> > 2. Pause JS execution
> > 3. Find an object inside the snapshot
> > 4. Ask the inspector to notify me when it gets destructed
> > 5. continue JS execution
> >
> > alternatively, some API for doing this like:
> > ```
> > let object = new Array(someLargeNumber);
> > console.onDestruction(object, function callback() { ... });
>
> This sounds very similar to the mark/paint feature request:
> <<a href="https://webkit.org/b/154410">https://webkit.org/b/154410</a>> Web Inspector: Programmatically mark/paint
> objects for heap snapshot
>
> If you could console.mark(object, "Tag") and then search for all the objects
> with "Tag" in the Snapshot, that would make it easy to find the object in
> and across snapshots.
>
> What is it you want to actually do with the object once you've seen it was
> collected. Just log?</span >
For my use case I wanted to just confirm that it was collected. I basically wanted an intuitive way of finding out that information that didn't require digging through a snapshot. So I think this other proposal would make that easy. I want Inspector to *tell* me that something has died, instead of me inferring that by seeing that the particular object I'm interested in is not in a particular snapshot.</pre>
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