Error: null is not an object (evaluating 'new a.Image')

[dreamofabear]

Error: null is not an object (evaluating 'new a.Image')
at Image (https://raw.githubusercontent.com/ampproject/amphtml/1908121824440/src/window-interface.js:95)
at iframe (https://raw.githubusercontent.com/ampproject/amphtml/1908121824440/src/pixel.js:61)
at win (https://raw.githubusercontent.com/ampproject/amphtml/1908121824440/extensions/amp-analytics/0.1/transport.js:246)
at (https://raw.githubusercontent.com/ampproject/amphtml/1908121824440/extensions/amp-analytics/0.1/transport.js:132)
at requestUrl (https://raw.githubusercontent.com/ampproject/amphtml/1908121824440/extensions/amp-analytics/0.1/requests.js:260)

My guess is the window is destroyed by the time Transport.sendRequest is called. A null check may fix it.

/cc @ampproject/wg-analytics

[Enriqe]

@ampproject/wg-analytics @dvoytenko any updates here?

Still seeing 5.9k occurrences in the current 2001251659540 canary.

[dvoytenko]

@zhouyx, is there some more magic we could do to bring this number down a bit more?

[dreamofabear]

My guess is the window is destroyed by the time Transport.sendRequest is called. A null check may fix it.

Have we tried doing this?

[zhouyx]

No we haven't, shall i try checking the win before creating the pixel?

amphtml/extensions/amp-analytics/0.1/transport.js

Lines 243 to 245 in 47a4915

	static sendRequestUsingImage(win, request, suppressWarnings, referrerPolicy) {
	const image = createPixel(win, request.url, referrerPolicy);
	loadPromise(image)

but I think the window is the value from this.win_ which is cached? Do you think it will help?

[dvoytenko]

Hmm. It seemed like the stack traces were circling around Transport.sendRequest. But that API is not used for pixel, is it?

[dvoytenko]

Oh. Just figured it out.

[dvoytenko]

So, yeah, I think the problem is here:

amphtml/src/pixel.js

Line 74 in 47a4915

const image = new Image();

So we just need to bailout there or somewhere before then when win == null

[zhouyx]

Ah so we pass in param by reference, makes sense. I'll create a quick fix.

[dvoytenko]

The reason why it's hard to notice is probably b/c of the const Image = WindowInterface.getImage(win) in the:

const Image = WindowInterface.getImage(win);
const image = new Image();

It most likely gets inlined by the compiler, thus simply becoming:

const image = new win.Iimage();

[rcebulko]

This is still occurring, and seems to occur only on iPhone. We have a new occurrence of this error appearing in Beta and Experimental exclusively on https://www-corriere-it.cdn.ampproject.org/ pages. It started last night 2020-03-11 some time 8pm-10pm, I'm guessing from a change they pushed to their site. It's currently reporting around 1000 errors an hour; that number will go up 10x if/when those releases are promoted.