Using Docker executor with image buildstream/testsuite-debian:9-master-123-7ce6581b ...
Pulling docker image buildstream/testsuite-debian:9-master-123-7ce6581b ...
Using docker image sha256:38f4a396dc81ff4b1d932443e9128db24704ff9ffba361dfa0a5b06da096a745 for buildstream/testsuite-debian:9-master-123-7ce6581b ...
section_start:1544554103:prepare_script
Running on runner-a334e492-project-1975139-concurrent-0 via runner-a334e492-gitlab-runner-autoscale-1544550948-bba0f06a...
section_end:1544554104:prepare_script
section_start:1544554104:get_sources
Cloning repository...
Cloning into '/builds/BuildStream/buildstream'...
Checking out 1b2c455f as richardmaw/shell-multi-stage...
fatal: reference is not a tree: 1b2c455fe6cc5887c96e98f97fba8e25996c2c56
section_end:1544554111:get_sources
section_start:1544554111:upload_artifacts_on_failure
section_end:1544554112:upload_artifacts_on_failure
ERROR: Job failed: exit code 1