Make whitespace (more) optional in list strings

[ryanwinchester]

CurrentlyPlug.Conn.Utils.list/1 would not handle all the whitespace around the commas if the space is before the comma.

According to what I understand from RFC9110§5.6.1, lists should look like:

element *( OWS "," OWS element )

With OWS (Optional White Space) on either side of the comma.

Right now I have it as handling only a single whitespace on either side, but we might have to clean up the string and then split, or clean it up after?

Examples

It should look like this:

iex> Plug.Conn.Utils.list("whitespace , is,optional")
["whitespace", "is", "optional"]

But it looks like this:

iex> Plug.Conn.Utils.list("whitespace , is,optional")
["whitespace ", "is", "optional"]

Discuss

• Do we want this behaviour?
• Do we handle more than one space on each side of the comma?
• What is the most performant way to handle it either way?

[josevalim]

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