Problem with justify text and comma in end of line

[manuthema]

Sometimes with justified text, the spaces between words are not well calculated and there is a space at the end of the line. This occurs when the line break coincides between a word and a comma. Previously (weasyprint 0.36) it happened that separated the comma from the word

I attach the minimum html with which I have been able to reproduce the problem.

I have the following versions:
weasyprint: 0.42.3
pango: 1.42.01

pruebaPDF.txt

[Tontyna]

I do understand what happens and what goes wrong but I'm unable to spot the place in source where to fix it. Ok, what happens:

The justify-me-text-block ist split into LineBoxes -- get_next_linebox calls split_inline_box etc.
The width of the individual LineBoxes is calculated in split_inline_box according to the text they contain.
This width should be the width of the line when left-aligned.

Via text_align justified lines then get some additional space inserted between their words. The space to insert is calculated as the differenence between the line's width and the available width.
This works fine as long as the given line width is correct.

In the case of the faulty aligned line split_inline_box has decided that the last bold BLA fits on the line and calculates a line-width including this BLA.
In the further processing the following comma wants to stick with the BLA and forces it onto the next line.
(I can see, that the comma would fit, too, on the previous line, but that's another story.)

In any case, problem and source of mis-justification is: The width of the LineBox from which the BLA was removed, is not updated. And text_align, not being informed about the shrinking, inserts almost no space at all between the words, an thats it.

I myself cannot find the place in source where to fix that. The layout-code muddles my brain...

[jiro412j]

I also experience the same problem
weasyprint: 0.42.3
pango: 1.42.01

[liZe]

Minimal use case:

<p style="text-align: justify; font-family: ahem; background-color: yellow; width: 7em">
a b <span>bla</span>,

[liZe]

The layout-code muddles my brain...

split_inline_box is a nightmare that I should rewrite.