Bug #15324: Dir.home test doesn't match actual Ruby or system behaviour

• Status: Closed
• Assignee: -
• Target version: -
• Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN

[chrisseaton (Chris Seaton)]

This test currently asserts that Dir.home(user) should return ENV['HOME'] if user is the current user.

We don't think this is correct - Dir.home(user) uses the expanded value of ~user, which explictly uses the login database, and explicitly not any current value of HOME.

See the documentation on tilde expansion here:

http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_01

"[if there is an explict user name after the tilde then] the tilde-prefix shall be replaced by a pathname of the initial working directory associated with the login name obtained using the getpwnam() function as defined in the System Interfaces volume of POSIX.1-2017 [as opposed to reading HOME]"

getpwnam is what File.expand_path does.

To see the problem, run MRI's test with HOME set to something else (again, see the link above to see that setting HOME is explicitly allowed).

$ HOME=/nothing make test-all
...
  1) Failure:
TestDir#test_home [/Users/chrisseaton/Documents/mri-test-upstream/ruby/test/ruby/test_dir.rb:378]:
<"/nothing"> expected but was
<"/Users/chrisseaton">.
...

We've encountered this test failure for real, so it isn't hypothetical.

The patch corrects the test to match actual Ruby behaviour.

[naruse (Yui NARUSE)]

• Status changed from Open to Closed

Applied in changeset trunk|r65926.

---

Use File.expand_path("~username") instead of ENV["HOME"]

File.expand_path("~username") uses getpwnam() independently from
Dir.home. [Bug #15324]

From: Chris Seaton [e-mail]

[MSP-Greg (Greg L)]

@naruse (Yui NARUSE)

Re r65926, I believe Windows has never processed '~'. Also, Window doesn't natively have ENV['USER'], but Ruby sets it. Regardless, the revised test fails...

Thanks, Greg

[MSP-Greg (Greg L)]

I'm mistaken. Windows 10 (Appveyor?) will process a plain '~'

The test should pass with:

        if windows?
          assert_equal(File.expand_path("~"), Dir.home(user))
        else
          assert_equal(File.expand_path("~#{user}"), Dir.home(user))
        end