Fix matching Git attributes using absolute paths

Git attributes can be defined using an absolute path. This commit fixes
the matching procedure so that attributes and paths with leading slashes
are supported properly.

lib/gitlab_git/attributes.rb

@@ -18,7 +18,7 @@ module Gitlab
     class Attributes
       # path - The path to the Git repository.
       def initialize(path)
-        @path = path
+        @path = File.expand_path(path)
         @patterns = nil
       end
@@ -28,8 +28,10 @@ module Gitlab
       #
       # Returns a Hash.
       def attributes(path)
+        full_path = File.join(@path, path)
+
         patterns.each do |pattern, attrs|
-          return attrs if File.fnmatch(pattern, path)
+          return attrs if File.fnmatch?(pattern, full_path)
         end
         {}
@@ -107,7 +109,7 @@ module Gitlab
           pattern, attrs = line.split(/\s+/, 2)
-          pairs << [pattern, parse_attributes(attrs)]
+          pairs << [File.join(@path, pattern), parse_attributes(attrs)]
         end
         # Newer entries take precedence over older entries.

spec/attributes_spec.rb

 require 'spec_helper'
 describe Gitlab::Git::Attributes do
-  let(:path) { File.join(SUPPORT_PATH, 'with-git-attributes.git') }
+  let(:path) do
+    File.expand_path(File.join(SUPPORT_PATH, 'with-git-attributes.git'))
+  end
   subject { described_class.new(path) }
@@ -29,6 +31,20 @@ describe Gitlab::Git::Attributes do
         expect(subject.attributes('foo.cgi')).
           to eq({ 'key' => 'value?p1=v1&p2=v2' })
       end
+
+      it 'returns a Hash containing the attributes for an absolute path' do
+        expect(subject.attributes('/test.txt')).to eq({ 'text' => true })
+      end
+
+      it 'returns a Hash containing the attributes when a pattern is defined using an absolute path' do
+        # When a path is given without a leading slash it should still match
+        # patterns defined with a leading slash.
+        expect(subject.attributes('foo.png')).
+          to eq({ 'gitlab-language' => 'png' })
+
+        expect(subject.attributes('/foo.png')).
+          to eq({ 'gitlab-language' => 'png' })
+      end
     end
     context 'using a path without any attributes' do
@@ -44,20 +60,20 @@ describe Gitlab::Git::Attributes do
     end
     it 'parses an entry that uses a tab to separate the pattern and attributes' do
-      expect(subject.patterns['*.md']).
+      expect(subject.patterns[File.join(path, '*.md')]).
         to eq({ 'gitlab-language' => 'markdown' })
     end
     it 'stores patterns in reverse order' do
       first = subject.patterns.to_a[0]
-      expect(first[0]).to eq('*.md')
+      expect(first[0]).to eq(File.join(path, '*.md'))
     end
     # It's a bit hard to test for something _not_ being processed. As such we'll
     # just test the number of entries.
     it 'ignores any comments and empty lines' do
-      expect(subject.patterns.length).to eq(7)
+      expect(subject.patterns.length).to eq(8)
     end
     it 'does not parse anything when the attributes file does not exist' do
@@ -97,7 +113,7 @@ describe Gitlab::Git::Attributes do
   describe '#each_line' do
     it 'iterates over every line in the attributes file' do
-      args = [String] * 11 # the number of lines in the file
+      args = [String] * 12 # the number of lines in the file
       expect { |b| subject.each_line(&b) }.to yield_successive_args(*args)
     end

spec/support/seed_helper.rb

@@ -54,6 +54,7 @@ module SeedHelper
 *.haml.*  gitlab-language=haml
 foo/bar.* foo
 *.cgi     key=value?p1=v1&p2=v2
+/*.png    gitlab-language=png
 # This uses a tab instead of spaces to ensure the parser also supports this.
 *.md\tgitlab-language=markdown