# Error syncing "TypeError: __str__ returned non-string (type NoneType)"

URL of experiment: https://pavlovia.org/hekragness/puppy-in-the-park

Description of the problem:

Syncing fine to Pavlovia all morning, all of a sudden getting this error:

``````Traceback (most recent call last):
File "C:\Program Files\PsychoPy3\lib\site-packages\psychopy\app\builder\builder.py", line 1221, in onPavloviaSync
self.fileExport(htmlPath=htmlPath)
File "C:\Program Files\PsychoPy3\lib\site-packages\psychopy\app\builder\builder.py", line 719, in fileExport
target="PsychoJS")
File "C:\Program Files\PsychoPy3\lib\site-packages\psychopy\scripts\psyexpCompile.py", line 73, in generateScript
compileScript(infile=exp, version=None, outfile=filename)
File "C:\Program Files\PsychoPy3\lib\site-packages\psychopy\scripts\psyexpCompile.py", line 242, in compileScript
_makeTarget(thisExp, outfile, targetOutput)
File "C:\Program Files\PsychoPy3\lib\site-packages\psychopy\scripts\psyexpCompile.py", line 214, in _makeTarget
script = thisExp.writeScript(outfile, target=targetOutput, modular=True)
File "C:\Program Files\PsychoPy3\lib\site-packages\psychopy\experiment\_experiment.py", line 260, in writeScript
self_copy._currentRoutine.writeEachFrameCodeJS(script, modular)
File "C:\Program Files\PsychoPy3\lib\site-packages\psychopy\experiment\routine.py", line 343, in writeEachFrameCodeJS
comp.writeFrameCodeJS(buff)
File "C:\Program Files\PsychoPy3\lib\site-packages\psychopy\experiment\components\movie\__init__.py", line 267, in writeFrameCodeJS
self.writeStopTestCodeJS(buff)
File "C:\Program Files\PsychoPy3\lib\site-packages\psychopy\experiment\components\_base.py", line 381, in writeStopTestCodeJS
buff.writeIndentedLines(code % self.params)
TypeError: __str__ returned non-string (type NoneType)
``````

All I did between this and the last sync was replace some .png files and change size parameters of image components. How on earth to troubleshoot this??

I also updated the conditions file in the loop (which is what is controlling presentation of the aforementioned images)

I have tried changing all the looping size/position parts of the image component and the text component in the routine that I was editing when this issue began. I also tried removing the .pngs that I edited since the last sync. Error persists.

Solved: a stray \$

Thanks for documenting! I am having a similar error-- did you find the stray \$ just by luck or did you find something in the output that pointed you to where it was?

Unfortunately if I recall correctly I think I found it by chance. I suspect that I put a \$ in one of the non-string fields of an image component.

Found mine, I had accidentally deleted a comma between the width and height on one of my components.

P.S. I was able to narrow down which component it was because each time I clicked on that component in builder, a message popped up in the runner reading:

``````8616.5473     ERROR     invalid syntax (<unknown>, line 1)
``````

and if I tried edit anything in the component, it would read:

``````8592.9439     ERROR     unexpected EOF while parsing (<unknown>, line 1)
``````

FYI I just had a similar problem in 2021.2.3 and the issue was that I had accidentally labeled the start time as 01 instead of 1.