From feb951d141b24ce1bead32e936b38a766bbdc54f Mon Sep 17 00:00:00 2001
From: Sascha Grunert <sgrunert@suse.com>
Date: Mon, 23 Mar 2020 11:52:22 +0100
Subject: [PATCH] Default to master branch in gcbmgr

A sane default for the branch in gcbmgr is the master branch, where we
can now simplify error handling paths as well.

Signed-off-by: Sascha Grunert <sgrunert@suse.com>
---
 cmd/krel/cmd/gcbmgr.go | 13 ++++---------
 docs/krel/gcbmgr.md    |  6 +++---
 2 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/cmd/krel/cmd/gcbmgr.go b/cmd/krel/cmd/gcbmgr.go
index 0963e91731a..b00faa71fe0 100644
--- a/cmd/krel/cmd/gcbmgr.go
+++ b/cmd/krel/cmd/gcbmgr.go
@@ -95,7 +95,7 @@ func init() {
 	gcbmgrCmd.PersistentFlags().StringVar(
 		&gcbmgrOpts.branch,
 		"branch",
-		"",
+		git.Master,
 		"Branch to run the specified GCB run against",
 	)
 
@@ -321,12 +321,7 @@ func setGCBSubstitutions(o *gcbmgrOptions) (map[string]string, error) {
 		gcbSubs["RC"] = ""
 	}
 
-	branch := o.branch
-	if branch == "" {
-		return gcbSubs, errors.New("Release branch must be set to continue")
-	}
-
-	gcbSubs["RELEASE_BRANCH"] = branch
+	gcbSubs["RELEASE_BRANCH"] = o.branch
 
 	if o.stage {
 		// TODO: Remove once we remove support for --built-at-head.
@@ -357,8 +352,8 @@ func setGCBSubstitutions(o *gcbmgrOptions) (map[string]string, error) {
 	gcbSubs["BUILDVERSION"] = buildVersion
 
 	kubecrossBranches := []string{
-		branch,
-		"master",
+		o.branch,
+		git.Master,
 	}
 
 	kubecrossVersion, kubecrossVersionErr := release.GetKubecrossVersion(kubecrossBranches...)
diff --git a/docs/krel/gcbmgr.md b/docs/krel/gcbmgr.md
index 8a59ccc0aaa..7dcee074c2c 100644
--- a/docs/krel/gcbmgr.md
+++ b/docs/krel/gcbmgr.md
@@ -35,7 +35,7 @@ Simply [install krel](README.md#installation).
 
 ```
 Flags:
-      --branch string          Branch to run the specified GCB run against
+      --branch string          Branch to run the specified GCB run against (default "master")
       --build-version string   Build version
       --gcb-config string      If provided, this will be used as the name of the Google Cloud Build config file. (default "cloudbuild.yaml")
       --gcp-user string        If provided, this will be used as the GCP_USER_TAG.
@@ -56,6 +56,8 @@ Global Flags:
 ## Important notes
 
 - Default executions of `krel gcbmgr` run in mock mode. To run an actual stage or release, you **MUST** provide the `--nomock` flag.
+- Note that the default `--branch` is set to `master`, which means that it needs
+  to be set to the release branch if necessary.
 - Always execute the release process in the following order:
   - mock stage: `krel gcbmgr --stage`
   - mock release: `krel gcbmgr --release`
@@ -81,7 +83,6 @@ Global Flags:
 
 ```shell
 krel gcbmgr --stage \
-  --branch master \
   --project kubernetes-release-test
 ```
 
@@ -89,7 +90,6 @@ krel gcbmgr --stage \
 
 ```shell
 krel gcbmgr --release \
-  --branch master \
   --project kubernetes-release-test \
   --build-version <build-version>
 ```