Fix release-staging cloudbuild job - hopefully

Signed-off-by: Nick Young <[email protected]>

Makefile

@@ -38,7 +38,10 @@ export BASE_REF ?= master
 # The commit hash of the current checkout
 # Used to pass a binary version for master,
 # overridden to semver for tagged versions.
-export COMMIT=$(shell git rev-parse --short HEAD)
+# Cloudbuild will set this in the environment to the
+# commit SHA, since the Prow does not seem to check out
+# a git repo.
+export COMMIT ?= $(shell git rev-parse --short HEAD)
 
 DOCKER ?= docker
 # TOP is the current directory where this Makefile lives.

cloudbuild.yaml

@@ -13,6 +13,7 @@ steps:
     - DOCKER_CLI_EXPERIMENTAL=enabled
     - GIT_TAG=$_GIT_TAG
     - BASE_REF=$_PULL_BASE_REF
+    - COMMIT=$_PULL_BASE_SHA
     args:
     - release-staging
 substitutions:
@@ -22,3 +23,5 @@ substitutions:
   # _PULL_BASE_REF will contain the ref that was pushed to to trigger this build -
   # a branch like 'master' or 'release-0.2', or a tag like 'v0.2'.
   _PULL_BASE_REF: 'master'
+  # _PULL_BASE_SHA will contain the Git SHA of the commit that was pushed to trigger this build.
+  _PULL_BASE_SHA: 'abcdef'