Comment by rmunn

The other problem I've personally seen with "tabs for indentation, spaces for alignment" is when your editor destroys your tab-space mix when it adjusts the indentation. I've personally seen an editor, I believe VS Code but I don't remember for certain (EDIT: on second thought it was probably Visual Studio, as my memory is placing me in an office I worked in around 2010 or 2011, before VS Code was created), turn a `<tab><tab><sp><sp>...<sp><sp>` line into `<tab><tab><tab><tab>...<tab>` when I intended or dedented it as part of a code block. I.e., I added or removed an `if:`, highlighted a section of code, and pressed the Tab or Shift-Tab shortcuts. And boom, that section of code was no longer in correct "tabs for indentation, spaces for alignment" syntax: the editor had converted a certain number of alignment spaces into tabs.

That was one of the moments that made me move away from tab characters in all circumstances. Because the only way to prevent that sort of thing from happening would be either to fix the editor bug (which I don't have time to do), or to turn on visible whitespace and pay close attention to whitespace every time I make an indentation change, knowing that the editor will sometimes do the wrong thing. I don't want to have to pay close attention to whitespace, and the only way I've found not to have to pay close attention is to either never align things at all, or never use tab characters. Tabs for indentation and spaces for alignment works great in theory, but in practice I have found I can't trust major editors to handle it right.