keg: handle the info directory file properly

If HOMEBREW_KEEP_INFO environment variable is set:
 - Do not symlink the info directory file (aka 'share/info/dir')
   otherwise it gets overwritten by next installed brew.
 - Install an entry in the directory for each linked info file when the
   brew is linked.
 - Uninstall the entry when the brew is unlinked.

Closes Homebrew/homebrew#9700.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

3 files changed, 36 insertions, 1 deletions

diff --git a/Library/Homebrew/cleaner.rb b/Library/Homebrew/cleaner.rb
index 426fbec6a..14a69c3ae 100644
--- a/Library/Homebrew/cleaner.rb
+++ b/Library/Homebrew/cleaner.rb
@@ -3,7 +3,14 @@ class Cleaner
     @f = Formula.factory f
     [f.bin, f.sbin, f.lib].select{ |d| d.exist? }.each{ |d| clean_dir d }
 
-    unless ENV['HOMEBREW_KEEP_INFO']
+    if ENV['HOMEBREW_KEEP_INFO']
+      # Get rid of the directory file, so it no longer bother us at link stage.
+      info_dir_file = f.info + 'dir'
+      if info_dir_file.file? and not f.skip_clean? info_dir_file
+        puts "rm #{info_dir_file}" if ARGV.verbose?
+        info_dir_file.unlink
+      end
+    else
       f.info.rmtree if f.info.directory? and not f.skip_clean? f.info
     end
 
diff --git a/Library/Homebrew/extend/pathname.rb b/Library/Homebrew/extend/pathname.rb
index 4ab94a502..1562bfbcd 100644
--- a/Library/Homebrew/extend/pathname.rb
+++ b/Library/Homebrew/extend/pathname.rb
@@ -262,6 +262,20 @@ class Pathname
   ensure
     chmod saved_perms if saved_perms
   end
+
+  def install_info
+    unless self.symlink?
+      raise "Cannot install info entry for unbrewed info file '#{self}'"
+    end
+    system '/usr/bin/install-info', self.to_s, (self.dirname+'dir').to_s
+  end
+
+  def uninstall_info
+    unless self.symlink?
+      raise "Cannot uninstall info entry for unbrewed info file '#{self}'"
+    end
+    system '/usr/bin/install-info', '--delete', '--quiet', self.to_s, (self.dirname+'dir').to_s
+  end
 end
 
 # sets $n and $d so you can observe creation of stuff
@@ -286,6 +300,14 @@ module ObserverPathnameExtension
     puts "ln #{to_s}" if ARGV.verbose?
     $n+=1
   end
+  def install_info
+    super
+    puts "info #{to_s}" if ARGV.verbose?
+  end
+  def uninstall_info
+    super
+    puts "uninfo #{to_s}" if ARGV.verbose?
+  end
 end
 
 $n=0
diff --git a/Library/Homebrew/keg.rb b/Library/Homebrew/keg.rb
index 8a98c1656..e6ef3e6a8 100644
--- a/Library/Homebrew/keg.rb
+++ b/Library/Homebrew/keg.rb
@@ -7,6 +7,8 @@ class Keg < Pathname
     raise "#{to_s} is not a directory" unless directory?
   end
 
+  INFOFILE_RX = %r[/share/info/[^.].*?\.info$]
+
   # if path is a file in a keg then this will return the containing Keg object
   def self.for path
     path = path.realpath
@@ -29,6 +31,7 @@ class Keg < Pathname
       next if src == self
       dst=HOMEBREW_PREFIX+src.relative_path_from(self)
       next unless dst.symlink?
+      dst.uninstall_info if dst.to_s =~ INFOFILE_RX and ENV['HOMEBREW_KEEP_INFO']
       dst.unlink
       n+=1
       Find.prune if src.directory?
@@ -127,7 +130,10 @@ protected
       dst.extend ObserverPathnameExtension
 
       if src.file?
+        # Do the symlink.
         dst.make_relative_symlink src unless File.basename(src) == '.DS_Store'
+        # Install info file entries in the info directory file
+        dst.install_info if dst.to_s =~ INFOFILE_RX and ENV['HOMEBREW_KEEP_INFO']
       elsif src.directory?
         # if the dst dir already exists, then great! walk the rest of the tree tho
         next if dst.directory? and not dst.symlink?