Add ability to set base ref for git_difference_expression
This makes it possible to do something like:
GIT_DIFF_BASE=20190904132002 ./scripts/changed_components.rb
which can come in handy.
@@ -20,7 +20,11 @@ end
current_rev = `git rev-parse HEAD`.chomp!
master_rev = `git rev-parse origin/master`.chomp!
-dev_rev = get_dev_manifest_sha
+dev_rev = if ENV['GIT_DIFF_BASE']
+ ENV['GIT_DIFF_BASE']
+ else
+ get_dev_manifest_sha
+ end
# check if the dev_rev is actually from this tree. we only expect to
# see this until we can get a build through dev.
