What is correct: widget.rowconfigure or widget.grid_rowconfigure?

If you browse Tkinter.py, you'll find that rowconfigure is just a reference to grid_rowconfigure.

widget.rowconfigure is literally just an alias for widget.grid_rowconfigure. In the source code for tkinter is this line of code:

rowconfigure = grid_rowconfigure

I don't know for a fact, but I suspect that widget.rowconfigure was just added for convenience. Frankly, I didn't even know it existed until I read this question.

In my opinion, grid_rowconfigure is the proper name to use. I say that because tkinter is an interface to an underlying tcl/tk interpreter, and in tcl/tk the command is grid rowconfigure. Since most tkinter functions mirror the naming conventions of the tcl/tk functions as close as possible, grid_rowconfigure is the natural choice.