The character to be repeated in order to create an input for which the analysed literal will have super-linear runtime behavior.
A literal that represents set.
E.g. if set only contained the character "a" (lower case A), then the literal may be /a/.
A single character that can be repeated to cause super-linear runtime.
The implementation is allowed to pick any character in set but makes a best effort to pick a
"humanly readable" character.
A non-empty set of characters that can be repeated to cause super-linear runtime.
CharSet is a class from the refa library.
Whether the polynomial backtracking of this report causes exponential backtracking.
A parent quantifier of [[quant]].
The maximum of this quantifier is at least 2.
This is guaranteed to be not the same quantifier as [[quant]].
An unbounded quantifier that can reach itself.
Returns a new literal with this cause of super-linear runtime being fixed. If the cause of this report could not
be automatically fixed, undefined will be returned.
A fixed literal is guaranteed to behave exactly the same as the analysed literal.
This report indicates super-linear runtime cause by polynomial backtracking of a quantifier with itself.
Examples
(?:a+){2},(?:a+)+Description
This type of super-linear runtime is the special case of the trade type ([[
TradeReport]]) where a quantifier trades characters with itself. As this requires some form of repetition of the quantifier, the self quantifier is always nested within a parent quantifier. The maximum of the parent quantifier determines the degree of polynomial backtracking (e.g./(a+){0,3}/backtracks in O(n^3) and/(a+)+/backtracks in O(2^n)).Fixing
To fix these reports, quantifier must be prevent from reaching itself. This can be accomplished by e.g. removing the quantifier (e.g.
/(?:a+)+/=>/(?:a)+/), using assertions (e.g./(a+|b){0,3}/=>/(a+(?!a)|b){0,3}/), or rewriting the affected parts of the pattern. Reports of simple cases usually have a fix for you.