Align force_encoding strategy into Trace::Stream

app/models/ci/job_trace_chunk.rb

@@ -28,7 +28,7 @@ module Ci
         raw_data
       else
         raise 'Unsupported data store'
-      end&.force_encoding(Encoding::BINARY)
+      end&.force_encoding(Encoding::BINARY) # Redis/Database return UTF-8 string as default
     end
 
     def set_data(value)

lib/gitlab/ci/trace.rb

@@ -43,7 +43,7 @@ module Gitlab
       end
 
       def append(data, offset)
-        write do |stream|
+        write('a+b') do |stream|
           current_length = stream.size
           return -current_length unless current_length == offset
 
@@ -75,7 +75,7 @@ module Gitlab
         stream&.close
       end
 
-      def write(mode = 'a+b')
+      def write(mode)
         stream = Gitlab::Ci::Trace::Stream.new do
           if current_path
             File.open(current_path, mode)

lib/gitlab/ci/trace/chunked_io.rb

@@ -114,7 +114,6 @@ module Gitlab
 
         def write(data)
           start_pos = tell
-          data = data.force_encoding(Encoding::BINARY)
 
           while tell < start_pos + data.bytesize
             # get slice from current offset till the end where it falls into chunk
@@ -178,7 +177,7 @@ module Gitlab
             current_chunk.tap do |chunk|
               raise FailedToGetChunkError unless chunk
 
-              @chunk = chunk.data.force_encoding(Encoding::BINARY)
+              @chunk = chunk.data
               @chunk_range = chunk.range
             end
           end

lib/gitlab/ci/trace/stream.rb

@@ -37,6 +37,8 @@ module Gitlab
         end
 
         def append(data, offset)
+          data = data.force_encoding(Encoding::BINARY)
+
           stream.truncate(offset)
           stream.seek(0, IO::SEEK_END)
           stream.write(data)
@@ -44,6 +46,8 @@ module Gitlab
         end
 
         def set(data)
+          data = data.force_encoding(Encoding::BINARY)
+
           stream.seek(0, IO::SEEK_SET)
           stream.write(data)
           stream.truncate(data.bytesize)
@@ -126,11 +130,11 @@ module Gitlab
             buf += debris
             debris, *lines = buf.each_line.to_a
             lines.reverse_each do |line|
-              yield(line.force_encoding('UTF-8'))
+              yield(line.force_encoding(Encoding.default_external))
             end
           end
 
-          yield(debris.force_encoding('UTF-8')) unless debris.empty?
+          yield(debris.force_encoding(Encoding.default_external)) unless debris.empty?
         end
 
         def read_backward(length)