Validate downstream branches exist.

Ensure that a change exists and is uploaded for each downstream
branch before allowing submit. If it does not, raise a user-facing
error so that they can correct it.

Change-Id: Ic488fd3144e31ed380879176f7a61ef330e9b0e0
3 files changed
tree: a14fa26dccd42eb3e40cda2a93b458e23a5693c1
  1. src/
  2. .gitignore
  3. BUILD
  4. external_plugin_deps.bzl
  5. LICENSE
  6. LICENSE-re2j