OpenEuphoria

1. join_path

• Posted by mattlewis (admin) Feb 22, 2013
• 1301 views

I was using join_path in std/filesys.e, and found what I think is probably a bug. Basically, I did (on Windows, obviously):

-- expected foo = `C:\foo\bar\baz` 
-- actual   foo = `\C:\foo\bar\baz` 
foo = join_path( { `C:\foo\bar`, "baz" } ) 

Is this a bug, or am I missing something about this function?

Matt

3. Re: join_path

• Posted by gbonvehi Feb 23, 2013
• 1236 views

-- expected foo = `C:\foo\bar\baz` 
-- actual   foo = `\C:\foo\bar\baz` 
foo = join_path( { `C:\foo\bar`, "baz" } ) 

As Greg quoted, it seems not to be a bug but the documented behavior. However, I wouldn't expect it to add the leading directory separator char as for example, if you're using relative paths, you wouldn't want it to be added.

Normally standard libraries concatenate the strings using the fsystem's directory separator char.

-- win 
foo = join_path( { `C:\foo\bar`, "baz" } ) 
-- foo = `C:\foo\bar\baz` 
foo = join_path( { `foo\bar`, "baz" } ) 
-- foo = `foo\bar\baz` 
 
-- *nix 
foo = join_path( { `/foo/bar`, "baz" } ) 
-- foo = `/foo/bar/baz` 
foo = join_path( { `foo/bar`, "baz" } ) 
-- foo = `foo/bar/baz` 

5. Re: join_path

• Posted by gbonvehi Feb 25, 2013
• 1161 views

I understand, but I still think this would be a problem, consider the following example.

include std/io.e 
include std/filesys.e 
constant READDIR = "../somedir" 
integer fn 
sequence filename 
filename = "test" 
fn = open(join_path({READDIR, filename}), "w") 
-- This would result in /../somedir which won't be what you expected. 

Edit:
Well, it's documented so it's kind of the expected behavior according to the docs so I won't discuss further.
I still think that it shouldn't add the leading separator as it invalidates all relative paths using this function and makes them absolute.

Edit2: Changing line 1987 in hg's version of filesys.e to

if match(":", elem) = 0 then 
-- Or, as we know that there cannot be more than a : and must be before any directory separator 
-- if i > 1 or match(":",elem) = 0  then  

instead of

if elem[$] != ':' then 

would solve the problem you're currently having as it only avoid appending the directory separator char if the sequence ends in : but not contains it.

Here is the corresponding test

test_equal("join_path #3", "C:\\Users\\john\\hello.txt", join_path({ "C:\\Users", "\\john\\", "hello.txt" })) 

Edit 3..:
Here's a patch with the changes: http://openeuphoria.org/pastey/205.wc
It also includes a fix for "canonical_path() #12:" test that fails in 64-bit when running in 32-bit as there are two Program Files shortened (PROGRA~1 = Program Files, PROGRA~2 = Program Files (x86)) and the canonical_path points to the second one.
I pointed it to Common Files instead which we have the guarantee that there's only one at the time.