FormatException when uploading two calculated files

[Mixolyde]

I have multiple dart projects in one repo, my build system is using these steps:

mkdir coverage
cd server
pub get
dart_coveralls calc --workers 2 --output ../coverage/server.lcov test/all.dart
cd ../client
pub get
dart_coveralls calc --workers 2 --output ../coverage/client.lcov test/all.dart
dart_coveralls upload --debug -T --token TOKEN ../coverage

The steps run and create the two LCOV files, but the last step fails with a FormatException:

Package root is /path/to/client/packages
Directory containing VM coverage files is /path/to/client/../coverage
Token is not empty
Exception
FormatException: Unexpected character (at character 1)
SF:/path/to/client/t...
^

dart:async                                       _Completer.completeError
package:coverage/src/hitmap.dart 75              parseCoverage.<async>.<fn>.<async>
===== asynchronous gap ===========================
dart:async                                       Future.wait
package:coverage/src/hitmap.dart 72              parseCoverage.<async>
===== asynchronous gap ===========================
dart:async                                       Future.Future.microtask
package:coverage/src/hitmap.dart                 parseCoverage
package:dart_coveralls/src/collect_lcov.dart 65  LcovCollector.convertVmReportsToLcov.<async>
===== asynchronous gap ===========================
dart:async                                       _asyncThenWrapperHelper
package:dart_coveralls/src/collect_lcov.dart     LcovCollector.convertVmReportsToLcov
package:dart_coveralls/src/cli_client.dart 86    CommandLineClient.convertAndUploadToCoveralls.<async>
===== asynchronous gap ===========================
dart:async                                       Future.Future.microtask
package:dart_coveralls/src/cli_client.dart       CommandLineClient.convertAndUploadToCoveralls
http://localhost:46782/src/upload.dart 64        UploadPart.execute.<async>.<fn>.<async>
===== asynchronous gap ===========================
package:stack_trace                              Chain.capture
http://localhost:46782/src/upload.dart 60        UploadPart.execute.<async>

The above happens in Linux. In Windows, I get the same thing, but with different paths.

[eseidelGoogle]

0.5.0 was released this morning, but I haven't done any work on the upload command, it may very well not have affected this bug.