Page crashes when using a long series of space characters

[lautmaus]

Some combinations of plain string and long series of space characters causes too much recursion and crashes the page:

a
                                                                                                                                                      
a

Tested here: https://probablyup.com/markdown-to-jsx/

[hectim]

Happening to us too. Initially thought it was because of image rendering, but firefox throws an exception about recursion depth so I believe its the same issue

[itsamejoshab]

Confirmed, ran into this with a block of SQL today that came from an IDE where whitespace was set to 4 spaces. The offending block of text:

WITH SalesByPrice AS
  (SELECT product_subcategory,
          ROUND(sale_price,2) AS sale_price,
          Avg(unit_qty_sold) unit_qty_sold,
          lag(sale_price, 1) OVER (PARTITION BY product_subcategory
                                   ORDER BY sale_price) Prevsale_price,
                                  lag(Avg(unit_qty_sold), 1) OVER (PARTITION BY product_subcategory
                                                                   ORDER BY sale_price) Prevunit_qty_sold

It took ~9 seconds to render

Tested here: https://probablyup.com/markdown-to-jsx/

[nx-victordiaz]

also on 7.4.0

[florianliebig]

I tracked this issue (or maybe a similar one?) down to

const CODE_BLOCK_R = /^(?: {4}[^\n]+\n*)+(?:\n *)+\n?/

https://github.com/quantizor/markdown-to-jsx/blob/acd970dc7be8f2390ed916fe1b1cf0874a8534f6/index.tsx#L186C1-L187C1

being checked in

markdown-to-jsx/index.tsx

Line 937 in acd970d

if (NON_PARAGRAPH_BLOCK_SYNTAXES.some(regex => regex.test(line))) {

Tester for catastrophic backtracing: https://regex101.com/r/85LH2r/1

For me, a suitable testcase in index.compiler.spec.tsx is

it('handles \\r\\n without crashing', () => {
  render(
    compiler(
      'Test \r\n                                                                                    \r\n Test'
    )
  )

  expect(root.innerHTML).toContain(`Test`)
})