Unknown plant in my garden - try it out for some time and see

When you create your own compost, from time to time, you will get plants that pop up from the compost (which is part of your potting mix), and it is your discretion about whether to let such plants remain their or not. And it is not only your own compost, but even compost or other additives that you get from elsewhere (or even the store bought potting mix) that might contain seeds. These seeds may lay dormant for some time, and then suddenly when temperature and weather conditions are right, the seeds germinate and the plant pops out of the soil - at which point you have to decide whether to keep the plant or not.
So, in one such case, I had multiple instances of a plant pop out; I took some photos and tried to find out what this plant actually was ? The photos were uploaded to a number of people who tried to detect what the photo actually was - but no conclusive answers. It was said that the plant could be a raspberry plant, but I don't remember planting raspberry seeds, so was not at all sure whether this could be a raspberry plant. Or it could be some other plant which will be clear when the flowers on the plant actually works out.

Now it is a matter of letting the plant grow, provide nutrients from time to time and see how it is faring. With some energy having been spent in ensuring that the plant has grown to this height, will not let it die.