path: path.Clean should not remove the last slash of a path

[stephane-archer]

dirpath := "./dir/"
dirpathclean:=path.Clean(dirpath)
if path.Dir(dirpath) != path.Dir(dirpathclean) {
    t.Fatal("WTF")
}

path.Clean should not remove the last slash of a path otherwise the rest of the path library doesn't have the appropriate behavior

[seankhliao]

Working as intended.

If clean was a no-op, it wouldn't need to exist.
Canonical names do not have trailing slashes.

[stephane-archer]

@seankhliao How do you know if the path represents a path to a directory or to a file? trailing slashes have that meaning, right? if you said that ./dir/ is the same as ./dir what about ./file.jpg/ and ./file.jpg?

[seankhliao]

nothing stops a directory from being called file.jpeg
a plain path does not preserve that information

[stephane-archer]

@seankhliao don't you think trailing slashes have a meaning? files will not have trailing slashes right?

[ianlancetaylor]

@stephane-archer At this time we aren't going to change the behavior of path.Clean. It is behaving as documented and intended. Thanks.

[stephane-archer]

@ianlancetaylor It's strange that path.Dir expects trailing slashes to work properly and path.Clean removes them. I can't get the logic, would you explain?

[ianlancetaylor]

It seems to me that your point about path.Dir doesn't hold if we assume that paths should normally not have trailing slashes. It's true that path.Dir("a/") returns "a", but that's only because of the unexpected trailing slash. path.Dir is not supposed to return a directory if the path refers to a directory; it's supposed to return the parent directory of whatever it is given, so that path.Dir("a") returns ".".

[stephane-archer]

I’m not sure if you notice but the function is named "Dir" not "Parent", maybe you should consider rename the function or give this function the behavior of its name. Le jeu. 4 mai 2023 à 17:39, Ian Lance Taylor ***@***.***> a écrit :

It seems to me that your point about path.Dir doesn't hold if we assume that paths should normally not have trailing slashes. It's true that path.Dir("a/") returns "a", but that's only because of the unexpected trailing slash. path.Dir is not supposed to return a directory if the path refers to a directory; it's supposed to return the parent directory of whatever it is given, so that path.Dir("a") returns ".". — Reply to this email directly, view it on GitHub <#59904 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAWX4PNBUPT2MVWF772VBY3XEQOXPANCNFSM6AAAAAAXRA3HBI> . You are receiving this because you were mentioned.Message ID: ***@***.***>

-- Best Regards, Stephane Archer

[ianlancetaylor]

Whether it was a mistake or not, we can't change it now, or we would break the Go 1 compatibility guarantee: https://go.dev/doc/go1compat.