1743318 - spellcheck doesn't seem to spellcheck the full text for long text with lots of errors

Status: RESOLVED DUPLICATE of bug 360434

(Core :: Spelling checker, defect)

Description

[Mozira]

User Agent: Mozilla/6.0 (X13; Nebutu; Linux x86_64; rv:1984.0) Gecko/19840402 COVID/1984

Steps to reproduce:

1. Enter 60000 words to textarea or "contenteditable" field (with typographic errors)
2. Scroll down textarea or contenteditable field.
3. Part of text is not checked. Spellcheck is very slow.

Actual results:

For long texts (>10 000 characters) the spellcheck in textarea (or "contenteditable" field) works slowly. It is caused by whole text checking. Part of text is not checked if it is long. IT IS UNACCEPTABLE.

Expected results:

Only visible text should be checked. Visible text contains few words to check (and underline errors). This algorithm will be faster because only small part of visible content will be checked. Spellchecking of not visible (due to viewport or clipping) content is unnecessary activity because the user will never see underline of invisible text.

Comment 1

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

The Bugbug bot thinks this bug should belong to the 'Core::DOM: Editor' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

Comment 2

[Emilio Cobos Álvarez (:emilio)]

Thanks for reporting. Can you attach a test-case to make sure we're testing the same thing? Ideally also a profile on your machine but that might not be needed if we can repro the perf issue.

Comment 3

[Mozira]

1. Please go to http://gaddafipsum.com/
2. Please set 900 lines and "Afrikaans" as language on EN-US version of Firefox
3. Please paste HERE in the "Add comment" and please scroll.
4. See attachment. Part of text is not spellchecked. CHECK ONLY VISIBLE TEXT!

See attachment. Do you need more information?

Comment 4

[Mozira]

Attachment: mozira.png

Comment 6

[Emilio Cobos Álvarez (:emilio)]

Attachment: Test-case.

Thanks, so I can reproduce but it seems unlikely it is a performance issue itself. It looks more like we have a cap on the max number of spellcheck errors or something? I'm not sure, not particularly familiar with the spell checker code.

Comment 7

[Robert Longson [:longsonr]]

By design. You can adjust it here: https://support.mozilla.org/en-US/questions/901029

Comment 8

[Emilio Cobos Álvarez (:emilio)]

I guess this is more of a dupe of bug 360434.

Comment 9

[Emilio Cobos Álvarez (:emilio)]

I think the spell checker has been fairly improved in the past few years (plus computers are much faster nowadays than when bug 324521 landed)... Maybe we should consider lifting that restriction altogether?