Attributes containing `"` cannot be parsed, even when escaped with `\`

[faytecCD]

Description

When using tag attributes, for example when the value of the name attribute contains a double quote ("), parsing fails even if the quote is escaped with a backslash (\) (added via addslashes).

This makes it impossible to use usernames or display names that contain double quotes.

Reproduction

[mention id=1 name="foo\"ff\""][/mention]

Expected Behavior

The value of name should be parsed as:

foo"ff"

Actual Behavior

Parsing fails and the original text is returned unchanged.

Impact

• Double quotes cannot be safely used inside attribute values

Notes

• Escaping with \" has already been tried
• The only possible workaround seems to be adjusting TOKEN_DELIMITER
• I am using RegularParser

Workaround

• Use content instead of an attribute

[mention id=1]foo"ff"[/mention]

This currently works.