path, path/filepath: document that Clean removes trailing slash

[gopherbot]

by Scheintoter:

What steps will reproduce the problem?
My problem is with the functions path.Clean and filepath.Clean.
They remove a trailing slash at the end of a path.
After reading the documentation I thought it would keep that slash.
Could you please fix the bug or if it is intended that way change the documentation?
Example:
testPath := "/this/is/a/test/"
fmt.Printf("original: %s\n", testPath)
fmt.Printf("cleaned path: %s\n", path.Clean(testPath))
fmt.Printf("cleaned filepath: %s\n", filepath.Clean(testPath))    

full program at:
http://play.golang.org/p/l1L6kGlYLE

What is the expected output?
original: /this/is/a/test/
cleaned path: /this/is/a/test/
cleaned filepath: /this/is/a/test/      (on linux)
cleaned filepath: \this\is\a\test\      (on windows)

What do you see instead?
original: /this/is/a/test/
cleaned path: /this/is/a/test
cleaned filepath: /this/is/a/test      (on play.golang.org)
cleaned filepath: \this\is\a\test      (on my windows computer)


Which compiler are you using (5g, 6g, 8g, gccgo)?
Not sure was is behind the go.exe from the go1 release

Which operating system are you using?
Windows 7 64 bit

Which version are you using?  (run 'go version')
go version go1

[minux]

Comment 1:

why it shouldn't remove the trailing path separator?

[minux]

Comment 2:

why it shouldn't remove the trailing path separator?

[gopherbot]

Comment 3 by Scheintoter:

Both ways are fine with me, but at http://golang.org/pkg/path/#Clean it isn't mentioned
and I don't want my program to break just because the compiler was made compliant with
the definition.
So I just want to know if I have to expect a change in the definition or a change in the
implementation of the compiler

[robpike]

Comment 4:

If the documentation is unclear should be updated. The returned path will be as clean as
it can be.

Labels changed: added priority-soon, documentation, removed priority-triage.

Owner changed to @robpike.

Status changed to Accepted.

[gopherbot]

Comment 5 by jo@durchholz.org:

The trailing slash should be removed.
That way, the cleaned path will work not just for directories but for files as well.
The main description is clear ("shortest equivalent"), but the detail explanation on
http://golang.org/pkg/path/filepath/#Clean shoud list trailing slash removal as fifth
point.

[rsc]

Comment 6:

Note that Clean does not remove the trailing slash in "/".
I am not sure what it does for `C:\` on Windows, but I
suspect it leaves the trailing slash there too.

Labels changed: added go1.1.

[gopherbot]

Comment 7 by Scheintoter:

I don't think removing the trailing slash keeps the path equivalent.
"/this/is/a/"+"test.txt"
is something else than
path.Clean("/this/is/a/")+"test.txt"

[rsc]

Comment 8:

path.Clean("/this/is/..")+"test.txt" changes too.
That's not something we promise.

[robpike]

Comment 9:

This issue was closed by revision 5fc2af1.

Status changed to Fixed.

[robpike]

Comment 10:

This issue was closed by revision 017c74115061.