[1.0.10-rc.1] TypeError: Cannot read property 'branch' of null

[ghost]

Test Device

MacBook Air

Operating System

macOS 10.13.5

Browser

Google Chrome 67.0.3396.79

Problem Description

For phetsims/qa/issues/128. Found in https://phet-dev.colorado.edu/html/circuit-construction-kit-black-box-study/1.0.10-rc.1/circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone. I connected multiple wires, the sim became uninteractable, and I saw this error in the console:

Uncaught TypeError: Cannot read property 'branch' of null
    at e.propagate (circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:938)
    at e.step (circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:938)
    at e.step (circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:938)
    at e.step (circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:939)
    at i.stepSimulation (circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965)
    at i.runAnimationLoop (circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965)
propagate @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:938
step @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:938
step @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:938
step @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:939
stepSimulation @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965
requestAnimationFrame (async)
runAnimationLoop @ circuit-construction-kit-black-box-study_en-phetio.html?phet-io.standalone:965

Steps to Reproduce

I haven't been able to reproduce yet, and it looks like something CT would throw. I'll try fuzzing for a while.

Visuals

[ghost]

Wrong repo. Closing and reposting in CKKBBS.

[zepumph]

SEE phetsims/circuit-construction-kit-black-box-study#67