Document trailing space handling in opaque URL paths #41127
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| For non-hierarchical schemes, the pathname is known as an _opaque path_ (meaning, the URL parser does not try to split it into a list of segments). In this case, an empty path results in the `pathname` property being the empty string. Trailing spaces in opaque paths are stripped during initial parsing if the `hash` and `search` are both empty; otherwise, they are percent-encoded as `%20` even when `hash` and `search` are later set to empty strings. | ||
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| > [!NOTE] | ||
| > Percent-encoding trailing spaces in opaque paths is not widely implemented. Some browsers implement the old behavior of stripping trailing spaces from `pathname` whenever the `hash` and `search` properties are both empty strings. In these browsers, setting `hash` or `search` may change the `pathname` as well. |
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Those setters with side effects have also only been in place for a relatively short period so older browsers do not even have that and instead end up with a trailing space in the path that would disappear after a serialize-then-parse.
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Arguably this "even older behavior" is a bug, and has been gone for 2 years already, so I opted to not include it because it makes things even more complicated—it's fine to only document the status quo and not history, and I only included this note because of current divergence, not because of historical change. I've filed a BCD issue to get both behaviors' versions recorded, so this should be backed by real data soon. Of course if you have some wording suggestion in mind, I would be happy to make it more complete
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Not encoding to %20 is also a bug at this point though. 😊
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I've updated with mentioning of the even-older behavior |
Fix #23320. See also mdn/browser-compat-data#27856
cc @annevk to see if this makes sense