1984312 - "Break on node removal" doesn't break when setting the parent node's innerHTML

Status: RESOLVED FIXED

(DevTools :: Debugger, defect)

Description

[Holger Benl [:hbenl]]

STR:

• open https://hbenl.github.io/test/innerhtml/
• open the inspector and set "Break on node removal" on the inner <div> surrounding the text "To replace"
• click the "Replace" button

Expected:

• the debugger breaks in the onclick handler of the button

Actual:

• the debugger doesn't break

I noticed this while investigating Bug 1982549 (and was able to work around it by selecting "Break on subtree modification" on the parent node).

Comment 1

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)(PTO: 6/26-6/30))]

While I'm removing the legacy DOM mutation events, I found this bug.

Comment 2

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)(PTO: 6/26-6/30))]

Probably, regression of bug 1694548.

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1694548

Comment 4

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)(PTO: 6/26-6/30))]

It's caused by bugs in hot paths. So, it's not safe to uplift.

Comment 5

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)(PTO: 6/26-6/30))]

https://treeherder.mozilla.org/jobs?repo=try&revision=10c291c9ea2f784e60a66fb1e90a590427c1069a

Comment 6

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)(PTO: 6/26-6/30))]

Attachment: Bug 1984312 - Make `nsContentUtils::HasMutationListeners()` and `nsContentUtils::WantMutationEvents()` be aware of DevTools r=smaug!,#dom-core

"Node Removal" of "Break on..." of DevTools listens to
"devtoolschildremoved" event which is dispatched immediately before
"DOMNodeRemoved" event by nsContentUtils::MaybeFireNodeRemoved().
However, some callers stops calling that if
nsContentUtils::HasMutationListeners() or
nsContentUtils::WantMutationEvents() return false, for example,
nsINode::ReplaceChildren() [1].

Therefore, they should return true if the type is
NS_EVENT_BITS_MUTATION_NODEREMOVED and DevTools is observing the
mutations.

As far as I've checked, there is no test of this feature. I guess it's
impossible due to breaking the running JS. Therefore, this patch does
not contain a new test.

1. https://searchfox.org/firefox-main/rev/856a307913c2b73765b4e88d32cf15ed05549cae/dom/base/nsINode.cpp#2354-2356

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/696347b90f6b
https://hg.mozilla.org/integration/autoland/rev/ab5fc5f25147
Make `nsContentUtils::HasMutationListeners()` and `nsContentUtils::WantMutationEvents()` be aware of DevTools r=smaug,dom-core

Comment 8

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/ab5fc5f25147