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Simpler "use the correct symlink" checks

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When determining whether to remove a symlink during unlinking, we check
three things:

  (a) Is the destination a symlink?
  (b) Does the destination exist?
  (c) Does the destination resolve to the source path?

However, since we know that the source path exists, (b) is guaranteed if
(a) and (c) are true. Thus checking (b) is unnecessary.

Similarly, when creating a new symlink during linking, we first check to
see if the link already exists by checking the same three criteria.
Again, checking (b) is unnecessary here.

See also the expanded test coverage in b52b579b.

Addendum: although we know that the source path exists during unlinking,
it doesn't matter. If the source path does not exist, then we still know
we have a broken symlink pointing into the keg we are unlinking, and
removing that symlink is still safe.
This commit is contained in:
Jack Nagel 2014-07-04 17:22:58 -05:00
parent f666b76c39
commit 810b5838b2
1 changed files with 2 additions and 2 deletions
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4
Library/Homebrew/keg.rb
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@ -192,7 +192,7 @@ class Keg
dirs << dst if dst.directory? && !dst.symlink?
# check whether the file to be unlinked is from the current keg first
next if !dst.symlink? || !dst.exist? || src != dst.resolved_path
next unless dst.symlink? && src == dst.resolved_path
dst.uninstall_info if dst.to_s =~ INFOFILE_RX
dst.unlink
@ -337,7 +337,7 @@ class Keg
end
def make_relative_symlink dst, src, mode
if dst.symlink? && dst.exist? && dst.resolved_path == src
if dst.symlink? && src == dst.resolved_path
puts "Skipping; link already exists: #{dst}" if ARGV.verbose?
return
end