Bug 95714 – Remove fixPlaceholderRenderer hack

• Status: RESOLVED
• Resolution: WONTFIX
• Component: DOM

[Shinya Kawanaka]

To show mouse cursor in the front of placeholder, we have adopted fixPlaceholderRenderer hack.
However, this is very fragile when we add an AuthroShadowRoot on <textarea> or <input> element.

[Shinya Kawanaka]

Created attachment 161991 [details]
WIP

[Shinya Kawanaka]

-webkit-user-select: none; will solve the problem, maybe.

[Shinya Kawanaka]

Created attachment 161995 [details]
WIP

[Kent Tamura]

(In reply to comment #2)
> -webkit-user-select: none; will solve the problem, maybe.

I remember it didn't work.

1. Applying Attachment #161995 [details]
2. Build Chromium port, or
   Build Mac port on Lion or Mountain Lion, or
   Build Mac port on SnowLoepard with RenderThemeMac::shoudlShowPlaceholderWhenFocused()==true
3. Open a document with <input placeholder=placeholder autofocus>
4. Type 'a', and Backspace

ASSERTION FAILED: !m_anchorNode || !m_anchorNode->isShadowRoot()
/Volumes/d2/WebKit/Source/WebCore/dom/Position.cpp(88) : WebCore::Position::Position(PassRefPtr<WebCore::Node>, WebCore::Position::LegacyEditingOffset)
1   0x103ff7a64 WebCore::Position::Position(WTF::PassRefPtr<WebCore::Node>, WebCore::Position::LegacyEditingOffset)
2   0x103ff797b WebCore::Position::Position(WTF::PassRefPtr<WebCore::Node>, WebCore::Position::LegacyEditingOffset)
3   0x102da754a WebCore::createLegacyEditingPosition(WTF::PassRefPtr<WebCore::Node>, int)
4   0x102e3d258 WebCore::RangeBoundaryPoint::toPosition() const
5   0x103294cd3 WebCore::Range::endPosition() const
6   0x1046f9fba WebCore::previousBoundary(WebCore::VisiblePosition const&, unsigned int (*)(unsigned short const*, unsigned int, unsigned int, WebCore::BoundarySearchContextAvailability, bool&))
7   0x1046f91f9 WebCore::startOfWord(WebCore::VisiblePosition const&, WebCore::EWordSide)
8   0x10339e7ef WebCore::Editor::respondToChangedSelection(WebCore::VisibleSelection const&, unsigned int)
9   0x1034ccf4e WebCore::FrameSelection::setSelection(WebCore::VisibleSelection const&, unsigned int, WebCore::FrameSelection::CursorAlignOnScroll, WebCore::TextGranularity)
10  0x1034d0499 WebCore::FrameSelection::textWasReplaced(WebCore::CharacterData*, unsigned int, unsigned int, unsigned int)
11  0x102f1b12e WebCore::CharacterData::setDataAndUpdate(WTF::String const&, unsigned int, unsigned int, unsigned int)
12  0x102f1b879 WebCore::CharacterData::deleteData(unsigned int, unsigned int, int&)
13  0x103173e45 WebCore::DeleteFromTextNodeCommand::doApply()
14  0x102f66dbb WebCore::CompositeEditCommand::applyCommandToComposite(WTF::PassRefPtr<WebCore::EditCommand>)
15  0x102f68b47 WebCore::CompositeEditCommand::deleteTextFromNode(WTF::PassRefPtr<WebCore::Text>, unsigned int, unsigned int)
16  0x10317706d WebCore::DeleteSelectionCommand::deleteTextFromNode(WTF::PassRefPtr<WebCore::Text>, unsigned int, unsigned int)
17  0x10317779f WebCore::DeleteSelectionCommand::handleGeneralDelete()
18  0x10317a766 WebCore::DeleteSelectionCommand::doApply()
19  0x102f66dbb WebCore::CompositeEditCommand::applyCommandToComposite(WTF::PassRefPtr<WebCore::EditCommand>)
20  0x102f69832 WebCore::CompositeEditCommand::deleteSelection(WebCore::VisibleSelection const&, bool, bool, bool, bool, bool)
21  0x1046ed5fc WebCore::TypingCommand::deleteKeyPressed(WebCore::TextGranularity, bool)
22  0x1046ec625 WebCore::TypingCommand::deleteKeyPressed(WebCore::Document*, unsigned int, WebCore::TextGranularity)
23  0x10338e5ee WebCore::Editor::deleteWithDirection(WebCore::SelectionDirection, WebCore::TextGranularity, bool, bool)
24  0x1033a4b07 WebCore::executeDeleteBackward(WebCore::Frame*, WebCore::Event*, WebCore::EditorCommandSource, WTF::String const&)
25  0x1033a4100 WebCore::Editor::Command::execute(WTF::String const&, WebCore::Event*) const
26  0x1033a42e9 WebCore::Editor::Command::execute(WebCore::Event*) const
27  0x1012485f2 WebKit::WebPage::executeKeypressCommandsInternal(WTF::Vector<WebCore::KeypressCommand, 0ul> const&, WebCore::KeyboardEvent*)
28  0x1012493af WebKit::WebPage::handleEditingKeyboardEvent(WebCore::KeyboardEvent*, bool)
29  0x1011cdf96 WebKit::WebEditorClient::handleKeyboardEvent(WebCore::KeyboardEvent*)
30  0x10338c972 WebCore::Editor::handleKeyboardEvent(WebCore::KeyboardEvent*)
31  0x1033eb651 WebCore::EventHandler::defaultKeyboardEventHandler(WebCore::KeyboardEvent*)

[WebKit Review Bot]

Comment on attachment 161995 [details]
WIP

Attachment 161995 [details] did not pass chromium-ews (chromium-xvfb):
Output: http://queues.webkit.org/results/13755321

New failing tests:
fast/forms/textarea-placeholder-visibility-2.html
fast/forms/input-placeholder-visibility-1.html
fast/forms/textarea-placeholder-visibility-1.html
fast/forms/input-placeholder-visibility-3.html

[Shinya Kawanaka]

Hmm... I couldn't reproduce it.

[Shinya Kawanaka]

(In reply to comment #6)
> Hmm... I couldn't reproduce it.

FYI: I tried it on Chromium Linux and Chromium Mac.

[Shinya Kawanaka]

Created attachment 162229 [details]
WIP

[Shinya Kawanaka]

This crash happens only when ShadowDOM flag is disabled.

[Shinya Kawanaka]

Created attachment 162395 [details]
Patch

[Kent Tamura]

Comment on attachment 162395 [details]
Patch

LGTM for WebCore/css and WebCore/html.

[Shinya Kawanaka]

Created attachment 162396 [details]
ChangeLog fixed

[Dimitri Glazkov (Google)]

Comment on attachment 162396 [details]
ChangeLog fixed

View in context: https://bugs.webkit.org/attachment.cgi?id=162396&action=review

> Source/WebCore/editing/visible_units.cpp:526
> +    // anchored and ShadowDOM is not enabled. We have to enable ShadowDOM, or avoid ShadowRoot anchored Position.

Why will it assert?

[Anders Carlsson]

Comment on attachment 162396 [details]
ChangeLog fixed

Clearing review flag on patches from before 2014. If this patch is still relevant, please reset the r? flag.

[Ryosuke Niwa]

No need to remove this hack since we don't support attaching a shadow root to an input element in V1 API.