margin_available logic imcompatable fot stock short

[sdmovie]

Expected Behavior

whenI short a stock and hold the negative position, my margin_available should be able to buy_back all the short position.

Actual Behavior

in process_order, and prviously all shorted stock, strategy instructs buyback:

size = order.size
if -1 < size < 1:
    size = np.sign(size) * int((self.margin_available * self._leverage * abs(size))
                                           // adjusted_price)

can buyback size is calculated as above, however the margin_available is calculated as :

margin_used = sum(trade.value / self._leverage for trade in self.trades)
return self.equity - margin_used   

in my case , initial captical 10000, shorted -193 CSCO @46$ , new price is 48$ then equity is 10000+380 profit =10380, this is correct. But the margin_used is 193*46 ~9000, the calculation results in margin available = equity(10380)-margin_used(~9000) =~1300$, then the buyback can only execute 26shares

Steps to Reproduce

Additional info

Branch Order

• Backtesting version:

[sdmovie]

absolute size of buy/sell seems being correct. It was the defasult percentage (0.95) has the issue.Will try furthur.
Absoulte size is no problem 'cause it's set size , not caculated by margin.
when there is a stock short position, the "cash" should be net equity +"frozen" short position value, thus you can always close short position as long as net equity is positive.
Anyway, absolute size can work~