Merge adjacent text nodes while appending

[mbrubeck]

Fixes #5828. r? @jdm or @kmcallister

[hoppipolla-critic-bot]

Critic review: https://critic.hoppipolla.co.uk/r/4788

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[mbrubeck]

Note: This only handles the append case. I'll file a follow-up issue to merge text nodes in append_before_sibling too. That will let us get rid of get_or_create completely.

[jdm]

Reviewed files:

• components/script/parse/html.rs @ r1

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^{components/script/parse/html.rs, line 159 [r1] (raw file):}
You can cast directly from Node->CharacterData instead

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Comments from the review on Reviewable.io

[mbrubeck]

^{components/script/parse/html.rs, line 159 [r1] (raw file):}
Done.

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Comments from the review on Reviewable.io

[jdm]

Reviewed files:

• components/script/parse/html.rs @ r2

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Comments from the review on Reviewable.io

[jdm]

+S-needs-squash -S-awaiting-review

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Comments from the review on Reviewable.io

[mbrubeck]

This breaks the following reftests

  * `acid2_noscroll.html == acid2_ref_broken.html`
  * `filter_inline_a.html == filter_inline_ref.html`
  * `text_align_complex_a.html == text_align_complex_ref.html`

filter_inline_a.html is broken because of a comment in a <style> element. Servo doesn't re-parse the <style> contents when an existing Text child is modified (#976).

I haven't determined yet whether the other two tests are broken for similar reasons or different ones.

[mbrubeck]

mbrubeck/servo@7f7ecc2 is a sketch of a solution to the filter_inline_a breakage. It does not fix the other two failures, though. :(

[Ms2ger]

And commented on critic

[mbrubeck]

text_align_complex_a is broken because html5ever calls append_text separately for each '\r'-separated line of text in the <style> element, and even if we re-parse after each call, we end up processing the CSS rules in a bad order (since we can't yet unload the results of previous parses).

[bors-servo]

☔ The latest upstream changes (presumably #6150) made this pull request unmergeable. Please resolve the merge conflicts.

[metajack]

@mbrubeck What's the plan for this?

[mbrubeck]

I think this is blocked until other improvements are made to stylesheet handling, like the ability to remove or modify an existing stylesheet (#976). Closing this for now.