There’s also a sample macro called “Trim Trailing Whitespace and Save” or something close to that, that conveniently does the action every time you save (well, every time you run the macro, which, if assigned to your favorite save-keycombo, e.g. Ctrl+s, will do it).

I used Ctrl+S remapped to Macros > Trim Trailing and Save for years before starting to use editorconfig – and actually I still use that mapping, because I don’t have a .editorconfig file at the root directory of all my drives, so there are still times when the editorconfig plugin doesn’t know to trim trailing for me. Since I almost exclusively use the keystroke vs the toolbar or menu command for my Save, I (almost) always get the trailing removed when I save.

I think the regex gurus need to take a look at this.

Actually, the python FunctionList definition regex is pretty simple:

• normal function: ^(async )?def\x20\K.+?(?=(:$|,$|:\s*#))
• function in class: \s(async )?def\x20\K.+?(?=(:$|,$|:\s*#))

The problem with both is that it requires the : or , to be the last character on the line (unless there’s a comment). If both are edited so the final lookahead is (?=(:\h*$|,\h*$|:\s*#)) (edit, save, exit NPP, restart NPP), then the original file, with the extra space, will work again.

Analysis: It turns out, because functionlist defaults to doing a .-matches-newline search, it is actually matching from def makefilenameprefix all the way to the ending : on the def readxppfileloop(options): line: this is why the makefilenameprefix made it into the function list, but readxppfileloop did not. (I think it actually means that there’s a multi-line string being sent to the FunctionList panel… but because it only displays one line per function, you don’t notice.)

If there had been an if xyz: line (or any other control structure that ended with :-then-EOL) somewhere inside makefilenameprefix(), then readxppfileloop would show up, too. So there was not only “bad luck” in having the space at the end of the line, and “bad luck” that whoever developed the original functionList regex for Python didn’t think to allow whitespace, but also “bad luck” that there wasn’t another control structure inside the function. Don’t go to your local casino until you’ve broken your “bad luck” streak. ;-)

I didn’t even see that space

And, that’s why it is best to have something in place that removes such things.

Is there an option to remove trailing whitespace in generic NPP?

Yes there is; on the Edit menu.
There’s also a sample macro called “Trim Trailing Whitespace and Save” or something close to that, that conveniently does the action every time you save (well, every time you run the macro, which, if assigned to your favorite save-keycombo, e.g. Ctrl+s, will do it).

Can the author add that option to the generic NPP settings?

Well, the author could, but it is probably unlikely as the functionality already exists in a plugin as well as the sample macro.

Can the author add that option to the generic NPP settings? There are 2 tabs for editor settings, “Editor 1” and “Editor 2”.

There’s some regex in a settings file somewhere for NPP that searches for function names. Can this be fixed to allow trailing spaces in the next NPP update?

I don’t know where that file is right now.

I do not have an solution but can confirm the behavior.

Now deleting the space at the end of makefilenameprefix solves it for me.

I think the regex gurus need to take a look at this.