cypress: [7.0.1]Bug: uploading a fixture break Cypress

I upgraded Cypress from 5.5.0 to 6.8.0 noticing a issue with the uploading from images as fixtures. This issue was present also when one manually uploads a image to the tested site. Since this issue, manifested after the update, I updated to 7.0.0 (and to 7.0.1 for that matter).

Current behavior

Cypress breaks when uploading an Image, thus stoping execution.

Test code to reproduce

This is the breaking part of the test, while “cy.wait(‘imageRequest’)” is open during it it breaks.

Due to some uncertainty in confindelity I sadly can’t publish the full test.

cy.fixture('testimage.png').as('image')
cy.get('.block').last().within(() => {
    cy.get('.grid-row .grid-column .plugin-image .form input[type=file]').then(function (el) {
    cy.wait('@imageRequest')
    // cy.wait('@pageSaveRequest')
    // convert the image base64 string to a blob
    const blob = Cypress.Blob.base64StringToBlob(this.image, 'image/png')

    const file = new File([blob], 'testimage.png', { type: 'image/png' })
    const list = new DataTransfer()

    list.items.add(file)
    const myFileList = list.files

    el[0].files = myFileList
    el[0].dispatchEvent(new Event('change', { bubbles: true }))
    })
})

Error Message

TypeError [ERR_INVALID_ARG_TYPE] [ERR_INVALID_ARG_TYPE]: The first argument must be of type string or an instance of Buffer or Uint8Array. Received type number (137)
    at write_ (_http_outgoing.js:696:11)
    at ClientRequest.write (_http_outgoing.js:661:15)
    at Request.write (/path/from/userTo/Caches/Cypress/7.0.1/Cypress.app/Contents/Resources/app/packages/server/node_modules/@cypress/request/request.js:1496:27)
    at /path/from/userTo/Caches/Cypress/7.0.1/Cypress.app/Contents/Resources/app/packages/server/node_modules/@cypress/request/request.js:546:20
    at Array.forEach (<anonymous>:null:null)
    at end (/path/from/userTo/Caches/Cypress/7.0.1/Cypress.app/Contents/Resources/app/packages/server/node_modules/@cypress/request/request.js:545:23)
    at Immediate._onImmediate (/path/from/userTo/Caches/Cypress/7.0.1/Cypress.app/Contents/Resources/app/packages/server/node_modules/@cypress/request/request.js:578:7)
    at processImmediate (internal/timers.js:461:21)
 {
  code: 'ERR_INVALID_ARG_TYPE'
}
TypeError [ERR_INVALID_ARG_TYPE] [ERR_INVALID_ARG_TYPE]: The first argument must be of type string or an instance of Buffer or Uint8Array. Received type number (137)
    at write_ (_http_outgoing.js:696:11)
    at ClientRequest.write (_http_outgoing.js:661:15)
    at Request.write (/path/from/userTo/Caches/Cypress/7.0.1/Cypress.app/Contents/Resources/app/packages/server/node_modules/@cypress/request/request.js:1496:27)
    at /path/from/userTo/Caches/Cypress/7.0.1/Cypress.app/Contents/Resources/app/packages/server/node_modules/@cypress/request/request.js:546:20
    at Array.forEach (<anonymous>:null:null)
    at end (/path/from/userTo/Caches/Cypress/7.0.1/Cypress.app/Contents/Resources/app/packages/server/node_modules/@cypress/request/request.js:545:23)
    at Immediate._onImmediate (/path/from/userTo/Caches/Cypress/7.0.1/Cypress.app/Contents/Resources/app/packages/server/node_modules/@cypress/request/request.js:578:7)
    at processImmediate (internal/timers.js:461:21)

Versions

It works in 5.5.0, from 6.0.1 it doesn’t work but did not brake, from 7.0.0 it breaks Cypress.