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> Note: my file manager even identifies the mime type without extension. That is how it should be

No, probing around the file content with a gazillion format-specific heuristics/hacks is not how it should be.

This is a security problem because it makes the probing code a giant attack surface, and there have been CVEs related to precisely that.

The file type should be determined from metadata only (simple, regular and without format-specific idiosyncrasies). Whether that metadata should be a suffix on the filename that's easy to mess up inadvertently is debatable, but Windows has the right idea here.

The .zip file and .xlsx/.docx is a good example of the complexity. It's popular to build certain application files (word docs, excel spreadsheets) that are zip files on the outside. Something with the first bytes 0x50 0x4d 0x03 0x04 (iirc) could be a zip file that the user wants to unzip or an application file that the user wants to open with an application. You need to probe deeper to guess which it is, or rely on the file extension.

> No, probing around the file content with a gazillion format-specific heuristics/hacks is not how it should be.

My favorite file browsers do it wonderfully. I don't even care when using network because performance is good enough and updates are done async.

> GNOME's nautilus, KDE's Dolphin and even Apple's finder do it right: press f2 and you can rename the file without changing the extension, unless you go out of you way for that.

This is exactly how Windows Explorer works by default too.

They introduced that feature a very long time ago too. I remember when they made the change because it made renaming files while having extensions visible was so much nicer. Hitting Ctrl-A to select everything in those cases where you do actually want to alter the extension is far easier than adjusting the selection to not include the extension for the common case where you don't want to change the extension.

IIRC that wasn't always the case. Maybe GP simply didn't use Windows since a long time.

But you're right, and I wanted to drop the same hint. As much as I dislike the OS, I have to admit they made some improvements.

So this changed recently. Didn't know that.

> Note: my file manager even identifies the mime type without extension. That is how it should be, changing the extension should not make the file harder to use. To this day, AFAIK, windows file manager still uses the extension to identify file type, thus allowing the user to easily change it may break expectation. GNOME's nautilus, KDE's Dolphin and even Apple's finder do it right: press f2 and you can rename the file without changing the extension, unless you go out of you way for that.

You've just confounded two different concerns: filetype identification by file managers and the interface to rename files. If you're not just cribbing some bad Intro to UX course, you'd know that Windows Explorer has always gone out of its way to howl bloody murder when you accidentally changed the file extension, and since Windows XP most rename file controls preserve the file extension. Your thinking was very sloppy here.

Identifying files by heuristics is a VERY dangerous game. Different systems have implemented it differently over the years, classic Mac OS in particular offering a fascinating alternative to file extensions.

> Also, once it is in the kernel, whoever change any internal api will fix every driver code to keep it working, so things that work once will work for a very long time.

Sometimes. Not always. Don't blindly worship code you haven't read.