Another RefExtractor refactor

lib/ref_extractor.rb

 # Module providing an extract_ref method for controllers working with Git
 # tree-ish + path params
-#
-# Given a string containing both a Git ref - such as a branch or tag - and a
-# filesystem path joined by forward slashes, attempts to separate the two.
-#
-# Expects a @project instance variable to contain the active project. Used to
-# check the input against a list of valid repository refs.
-#
-# Examples
-#
-#   # No @project available
-#   extract_ref('master')
-#   # => ['', '']
-#
-#   extract_ref('master')
-#   # => ['master', '/']
-#
-#   extract_ref("f4b14494ef6abf3d144c28e4af0c20143383e062/CHANGELOG")
-#   # => ['f4b14494ef6abf3d144c28e4af0c20143383e062', '/CHANGELOG']
-#
-#   extract_ref("v2.0.0/README.md")
-#   # => ['v2.0.0', '/README.md']
-#
-#   extract_ref('issues/1234/app/models/project.rb')
-#   # => ['issues/1234', '/app/models/project.rb']
-#
-#   # Given an invalid branch, we fall back to just splitting on the first slash
-#   extract_ref('non/existent/branch/README.md')
-#   # => ['non', '/existent/branch/README.md']
-#
-# Returns an Array where the first value is the tree-ish and the second is the
-# path
 module RefExtractor
+  # Thrown when given an invalid path
+  class InvalidPathError < StandardError; end
+
+  # Given a string containing both a Git ref - such as a branch or tag - and a
+  # filesystem path joined by forward slashes, attempts to separate the two.
+  #
+  # Expects a @project instance variable to contain the active project. Used to
+  # check the input against a list of valid repository refs.
+  #
+  # Examples
+  #
+  #   # No @project available
+  #   extract_ref('master')
+  #   # => ['', '']
+  #
+  #   extract_ref('master')
+  #   # => ['master', '']
+  #
+  #   extract_ref("f4b14494ef6abf3d144c28e4af0c20143383e062/CHANGELOG")
+  #   # => ['f4b14494ef6abf3d144c28e4af0c20143383e062', 'CHANGELOG']
+  #
+  #   extract_ref("v2.0.0/README.md")
+  #   # => ['v2.0.0', 'README.md']
+  #
+  #   extract_ref('issues/1234/app/models/project.rb')
+  #   # => ['issues/1234', 'app/models/project.rb']
+  #
+  #   # Given an invalid branch, we fall back to just splitting on the first slash
+  #   extract_ref('non/existent/branch/README.md')
+  #   # => ['non', 'existent/branch/README.md']
+  #
+  # Returns an Array where the first value is the tree-ish and the second is the
+  # path
   def extract_ref(input)
     pair = ['', '']
@@ -41,24 +43,28 @@ module RefExtractor
       # If the ref appears to be a SHA, we're done, just split the string
       pair = $~.captures
     else
+      # Otherwise, attempt to detect the ref using a list of the project's
+      # branches and tags
+
       # Append a trailing slash if we only get a ref and no file path
       id = input
       id += '/' unless id.include?('/')
-      # Otherwise, attempt to detect the ref using a list of the project's
-      # branches and tags
       valid_refs = @project.branches + @project.tags
       valid_refs.select! { |v| id.start_with?("#{v}/") }
       if valid_refs.length != 1
         # No exact ref match, so just try our best
-        pair = id.match(/([^\/]+)(.+)/).captures
+        pair = id.match(/([^\/]+)(.*)/).captures
       else
         # Partition the string into the ref and the path, ignoring the empty first value
         pair = id.partition(valid_refs.first)[1..-1]
       end
     end
+    # Remove leading slash from path
+    pair[1].gsub!(/^\//, '')
+
     pair
   end
 end

spec/lib/ref_extractor_spec.rb

@@ -11,29 +11,48 @@ describe RefExtractor do
     project.stub(:tags).and_return(['v1.0.0', 'v2.0.0'])
   end
-  it "extracts a ref without a path" do
-    extract_ref('master').should == ['master', '/']
-  end
-
-  it "extracts a valid branch ref" do
-    extract_ref('foo/bar/baz/CHANGELOG').should == ['foo/bar/baz', '/CHANGELOG']
-  end
-
-  it "extracts a valid tag ref" do
-    extract_ref('v2.0.0/CHANGELOG').should == ['v2.0.0', '/CHANGELOG']
-  end
-
-  it "extracts a valid commit ref" do
-    extract_ref('f4b14494ef6abf3d144c28e4af0c20143383e062/CHANGELOG').should ==
-      ['f4b14494ef6abf3d144c28e4af0c20143383e062', '/CHANGELOG']
-  end
-
-  it "falls back to a primitive split for an invalid ref" do
-    extract_ref('stable/CHANGELOG').should == ['stable', '/CHANGELOG']
-  end
-
-  it "returns an empty pair when no @project is set" do
-    @project = nil
-    extract_ref('master/CHANGELOG').should == ['', '']
+  describe '#extract_ref' do
+    it "returns an empty pair when no @project is set" do
+      @project = nil
+      extract_ref('master/CHANGELOG').should == ['', '']
+    end
+
+    context "without a path" do
+      it "extracts a valid branch" do
+        extract_ref('master').should == ['master', '']
+      end
+
+      it "extracts a valid tag" do
+        extract_ref('v2.0.0').should == ['v2.0.0', '']
+      end
+
+      it "extracts a valid commit ref without a path" do
+        extract_ref('f4b14494ef6abf3d144c28e4af0c20143383e062').should ==
+          ['f4b14494ef6abf3d144c28e4af0c20143383e062', '']
+      end
+
+      it "falls back to a primitive split for an invalid ref" do
+        extract_ref('stable').should == ['stable', '']
+      end
+    end
+
+    context "with a path" do
+      it "extracts a valid branch" do
+        extract_ref('foo/bar/baz/CHANGELOG').should == ['foo/bar/baz', 'CHANGELOG']
+      end
+
+      it "extracts a valid tag" do
+        extract_ref('v2.0.0/CHANGELOG').should == ['v2.0.0', 'CHANGELOG']
+      end
+
+      it "extracts a valid commit SHA" do
+        extract_ref('f4b14494ef6abf3d144c28e4af0c20143383e062/CHANGELOG').should ==
+          ['f4b14494ef6abf3d144c28e4af0c20143383e062', 'CHANGELOG']
+      end
+
+      it "falls back to a primitive split for an invalid ref" do
+        extract_ref('stable/CHANGELOG').should == ['stable', 'CHANGELOG']
+      end
+    end
   end
 end