Opening PopupBox brings "invalid LatLng object (NaN, 11.3850302945) in LatLng.js:32

Opening a popup box which is bound to an marker show the following error:

LatLng.js:32 Uncaught Error: Invalid LatLng object: (NaN, 11.385030294575534)
    at new LatLng (LatLng.js:32:9)
    at Object.unproject (Projection.SphericalMercator.js:35:10)
    at Object.pointToLatLng (CRS.js:41:26)
    at NewClass.unproject (Map.js:987:27)
    at NewClass.panInside (Map.js:536:20)
    at NewClass._panOnFocus (Marker.js:397:7)
    at HTMLDivElement.handler (DomEvent.js:108:13)
LatLng @ LatLng.js:32
unproject @ Projection.SphericalMercator.js:35
pointToLatLng @ CRS.js:41
unproject @ Map.js:987
panInside @ Map.js:536
_panOnFocus @ Marker.js:397
handler @ DomEvent.js:108

First, this behaviour is new since Leaflet 1.8.0 and second in the whole data there is no such longitude " 11.385030294575534". I think this is somewhere calculated. With Leaflet 1.7.1 I don’t get this error.

Environment

• Leaflet version: 1.8.0
• Browser (with version): Chromium 99.0.4844.84 / FireFox 99.0
• OS/Platform (with version): Ubuntu 18.04 (64-Bit)

[IvanSanchez]

@juedan Thanks! That certainly clarifies things.

However, I’ll close this bug as “user not following the API reference”. The iconSize option is supposed to be a L.Point, or an array of two numbers (and it should be obvious that the "auto" string is not a number). The fact that this way of defining icon sizes work at all is a chain of coincidences:

• L.Point is not enforcing any strict type checks
• When setting the size of the HTMLImageElement at …

https://github.com/Leaflet/Leaflet/blob/da386bec18d2e103acb207e97cf332bd388bb575/src/layer/marker/Icon.js#L145

…, the “sum” of "auto" + "px" is calculated as "autopx" (because that’s how ECMAscript works);

• Now, when setting a value of "autopx" for the CSS property “height”, the browser silently ignores that invalid value, and sets the CSS property “height” to a value of ""
• Finally, when the browser adds a HTMLImageElement to the DOM with an empty value for the height, its height is calculated from the intrinsic image height

All things considered, I think the bug is invalid because it relies on passing values contrary to what’s specified in the API documentation. Fetching the icon size from the intrinsic image dimensions is a possibility but is (a) out of the scope of this bug and (b) a potential source of asynchronous hell.

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As a side note: You just provided a reproducible use case, and I replied deciding that the bug is invalid… and maybe that makes you feel bad, or you feel that you wasted time on that reproducible use case. But: Please don’t! These things are informative, and clarifying, and overall good, and I do appreciate it!

[juedan]

As promised here an link for the test code: https://juedan.nerdcamp.net/Test/test_leaflet.html If the iconSize is set to [<pixel number>, "auto"] then an error is thrown. But with Leaflet 1.7.1 this works without any issues.