Merge branch '35942_api_binary_encoding' into 'master'

changelogs/unreleased/35942-api-binary-encoding.yaml

+---
+title: "Fix API to serve binary diffs that are treated as text."
+merge_request: 14038

lib/api/commits.rb

@@ -104,7 +104,7 @@ module API
 
         not_found! 'Commit' unless commit
 
-        commit.raw_diffs.to_a
+        present commit.raw_diffs.to_a, with: Entities::RepoDiff
       end
 
       desc "Get a commit's comments" do

lib/api/entities.rb

@@ -291,10 +291,11 @@ module API
     end
 
     class RepoDiff < Grape::Entity
-      expose :old_path, :new_path, :a_mode, :b_mode, :diff
+      expose :old_path, :new_path, :a_mode, :b_mode
       expose :new_file?, as: :new_file
       expose :renamed_file?, as: :renamed_file
       expose :deleted_file?, as: :deleted_file
+      expose :json_safe_diff, as: :diff
     end
 
     class ProtectedRefAccess < Grape::Entity

lib/gitlab/encoding_helper.rb

@@ -22,10 +22,10 @@ module Gitlab
 
       # return message if message type is binary
       detect = CharlockHolmes::EncodingDetector.detect(message)
-      return message.force_encoding("BINARY") if detect && detect[:type] == :binary
+      return message.force_encoding("BINARY") if detect_binary?(message, detect)
 
-      # force detected encoding if we have sufficient confidence.
       if detect && detect[:encoding] && detect[:confidence] > ENCODING_CONFIDENCE_THRESHOLD
+        # force detected encoding if we have sufficient confidence.
         message.force_encoding(detect[:encoding])
       end
 
@@ -36,6 +36,19 @@ module Gitlab
       "--broken encoding: #{encoding}"
     end
 
+    def detect_binary?(data, detect = nil)
+      detect ||= CharlockHolmes::EncodingDetector.detect(data)
+      detect && detect[:type] == :binary && detect[:confidence] == 100
+    end
+
+    def detect_libgit2_binary?(data)
+      # EncodingDetector checks the first 1024 * 1024 bytes for NUL byte, libgit2 checks
+      # only the first 8000 (https://github.com/libgit2/libgit2/blob/2ed855a9e8f9af211e7274021c2264e600c0f86b/src/filter.h#L15),
+      # which is what we use below to keep a consistent behavior.
+      detect = CharlockHolmes::EncodingDetector.new(8000).detect(data)
+      detect && detect[:type] == :binary
+    end
+
     def encode_utf8(message)
       detect = CharlockHolmes::EncodingDetector.detect(message)
       if detect && detect[:encoding]

lib/gitlab/git/blob.rb

@@ -42,14 +42,6 @@ module Gitlab
           end
         end
 
-        def binary?(data)
-          # EncodingDetector checks the first 1024 * 1024 bytes for NUL byte, libgit2 checks
-          # only the first 8000 (https://github.com/libgit2/libgit2/blob/2ed855a9e8f9af211e7274021c2264e600c0f86b/src/filter.h#L15),
-          # which is what we use below to keep a consistent behavior.
-          detect = CharlockHolmes::EncodingDetector.new(8000).detect(data)
-          detect && detect[:type] == :binary
-        end
-
         # Returns an array of Blob instances, specified in blob_references as
         # [[commit_sha, path], [commit_sha, path], ...]. If blob_size_limit < 0 then the
         # full blob contents are returned. If blob_size_limit >= 0 then each blob will
@@ -65,6 +57,10 @@ module Gitlab
           end
         end
 
+        def binary?(data)
+          EncodingHelper.detect_libgit2_binary?(data)
+        end
+
         private
 
         # Recursive search of blob id by path

lib/gitlab/git/diff.rb

@@ -116,6 +116,15 @@ module Gitlab
 
           filtered_opts
         end
+
+        # Return a binary diff message like:
+        #
+        # "Binary files a/file/path and b/file/path differ\n"
+        # This is used when we detect that a diff is binary
+        # using CharlockHolmes when Rugged treats it as text.
+        def binary_message(old_path, new_path)
+          "Binary files #{old_path} and #{new_path} differ\n"
+        end
       end
 
       def initialize(raw_diff, expanded: true)
@@ -190,6 +199,13 @@ module Gitlab
         @collapsed = true
       end
 
+      def json_safe_diff
+        return @diff unless detect_binary?(@diff)
+
+        # the diff is binary, let's make a message for it
+        Diff.binary_message(@old_path, @new_path)
+      end
+
       private
 
       def init_from_rugged(rugged)

spec/lib/gitlab/git/diff_spec.rb

@@ -273,6 +273,25 @@ EOT
     end
   end
 
+  describe '#json_safe_diff' do
+    let(:project) { create(:project, :repository) }
+
+    it 'fake binary message when it detects binary' do
+      # Rugged will not detect this as binary, but we can fake it
+      diff_message = "Binary files files/images/icn-time-tracking.pdf and files/images/icn-time-tracking.pdf differ\n"
+      binary_diff = described_class.between(project.repository, 'add-pdf-text-binary', 'add-pdf-text-binary^').first
+
+      expect(binary_diff.diff).not_to be_empty
+      expect(binary_diff.json_safe_diff).to eq(diff_message)
+    end
+
+    it 'leave non-binary diffs as-is' do
+      diff = described_class.new(@rugged_diff)
+
+      expect(diff.json_safe_diff).to eq(diff.diff)
+    end
+  end
+
   describe '#submodule?' do
     before do
       commit = repository.lookup('5937ac0a7beb003549fc5fd26fc247adbce4a52e')

spec/requests/api/commits_spec.rb

@@ -673,6 +673,12 @@ describe API::Commits do
           it_behaves_like 'ref diff'
         end
       end
+
+      context 'when binary diff are treated as text' do
+        let(:commit_id) { TestEnv::BRANCH_SHA['add-pdf-text-binary'] }
+
+        it_behaves_like 'ref diff'
+      end
     end
   end