Bug #13276: Dir.glob returns empty array when OS has no more file handles (expected exception)

• Status: Closed
• Assignee: nobu (Nobuyoshi Nakada)
• Target version: -
• ruby -v: ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-darwin14]
• Backport: 2.2: WONTFIX, 2.3: REQUIRED, 2.4: DONE

[floehopper (James Mead)]

The following terminal session demonstrates how Dir.glob returns an empty array when the OS has run out of file handles; whereas File.new raises a Errno::EMFILE exception.

I would expect Dir.glob to fail fast in a similar way to File.new.

$ mkdir /tmp/ruby-dir-glob-returns-empty-array-when-too-many-open-files
$ cd /tmp/ruby-dir-glob-returns-empty-array-when-too-many-open-files
$ touch foo
$ ulimit -n 16
$ ruby -e "1.upto(16).map { |i| p [i, Dir.glob('*')]; File.new('foo') }"
[1, ["foo"]]
[2, ["foo"]]
[3, ["foo"]]
[4, ["foo"]]
[5, ["foo"]]
[6, ["foo"]]
[7, ["foo"]]
[8, ["foo"]]
[9, ["foo"]]
[10, []] # Dir.glob returns empty array and does not raise exception
-e:1:in `initialize': Too many open files @ rb_sysopen - foo (Errno::EMFILE)
	from -e:1:in `new'
	from -e:1:in `block in <main>'
	from -e:1:in `upto'
	from -e:1:in `each'
	from -e:1:in `map'
	from -e:1:in `<main>'

The following is a counter example which shows how Dir.new raises an exception under the same conditions.

$ mkdir /tmp/ruby-dir-new-raises-exception-when-too-many-files-open
$ cd /tmp/ruby-dir-new-raises-exception-when-too-many-files-open
$ touch foo
$ mkdir bar
$ ulimit -n 16
$ ruby -e "1.upto(16).map { |i| p [i, Dir.new('bar')]; File.new('foo') }"
[1, #<Dir:bar>]
[2, #<Dir:bar>]
[3, #<Dir:bar>]
[4, #<Dir:bar>]
[5, #<Dir:bar>]
[6, #<Dir:bar>]
[7, #<Dir:bar>]
[8, #<Dir:bar>]
[9, #<Dir:bar>]
-e:1:in `initialize': Too many open files @ dir_initialize - bar (Errno::EMFILE)
	from -e:1:in `new'
	from -e:1:in `block in <main>'
	from -e:1:in `upto'
	from -e:1:in `each'
	from -e:1:in `map'
	from -e:1:in `<main>'

This is what I would expect for Dir.glob, i.e. I would expect an exception like this: Too many open files @ dir_s_glob (Errno::EMFILE) in the first example.

[floehopper (James Mead)]

• Subject changed from Ruby Dir.glob returns empty array when too many open files to Ruby Dir.glob returns empty array when too many open files (silent failure)

[floehopper (James Mead)]

• Subject changed from Ruby Dir.glob returns empty array when too many open files (silent failure) to Ruby Dir.glob returns empty array when OS has no more file handles (silent failure)

[floehopper (James Mead)]

• Subject changed from Ruby Dir.glob returns empty array when OS has no more file handles (silent failure) to Dir.glob returns empty array when OS has no more file handles (silent failure)

[floehopper (James Mead)]

• Subject changed from Dir.glob returns empty array when OS has no more file handles (silent failure) to Dir.glob returns empty array when OS has no more file handles (expected exception)

[floehopper (James Mead)]

• Description updated (diff)

[floehopper (James Mead)]

Bump?

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Assigned
• Assignee set to nobu (Nobuyoshi Nakada)

This bug predates 1.0, so it will be fixed by 2.5 but won't be backported.

[nobu (Nobuyoshi Nakada)]

• Status changed from Assigned to Closed

Applied in changeset trunk|r58156.

---

dir.c: err at glob failure

• dir.c (glob_helper): raise a SystemCallError exception when
  opendir() failed, except for ENOENT, ENOTDIR, and EACCES. this
  behavior predates 1.0; the comments in glob.c claimed that
  glob() returned -1 on error but actualy the pointer to a global
  variable, then dir_glob() did check only -1 as the comments, and
  ignored actual errors. [ruby-core:80226] [Bug #13276]

dir.c: ruby_glob_funcs_t

[usa (Usaku NAKAMURA)]

• Backport changed from 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN to 2.2: WONTFIX, 2.3: REQUIRED, 2.4: REQUIRED

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.2: WONTFIX, 2.3: REQUIRED, 2.4: REQUIRED to 2.2: WONTFIX, 2.3: REQUIRED, 2.4: DONE

ruby_2_4 r61367 merged revision(s) 58146,58150,58156.