Dynamically determine how many leds are in a strip

I am working on a project using the fastled 3.0 library to control a strip of leds. I'm using 3 wire leds not an SPI based chipset. Specifically I'm using lights with the TM1809 chipset if it proves to be relevant. The library is great, but the only downside is that I have to define how many leds are in my strip, and part of my project is to make it very simple extend the strip with more lights if I desire. Therefore, I need to be able to dynamically decide how many lights are connected to my yun.

Here's my thoughts:

as part of the setup loop, light up the leds one led at a time. If the led lights up, increment the led count if not assume we're at the end of the strip. My question for you is, is there some way of getting feedback to the arduino whether or not the lighting of the led was successful? I'm still digging through the documentation and code of the library but so far I'm not seeing anything.

This doesn't have to be library specific, just in general, the library uses pwm to control the lights

You're not going to get any feedback from the LEDs. If you know the size and placement of the project you could use a LDR or some other light sensor to tell when one of the lights was lit up, but that requires that all the lights are all close enough together and arranged such that the sensor can see them all.

Measure the current draw and guesstimate?

Thanks guys, I think I'm going to give AWOL's idea a try as it would prevent me from having to buy more components.

Put a LDR on the last LED, when it turns on you have your feed back.