feat: Add merge-method option

CHANGELOG.md

@@ -1,5 +1,11 @@
 # changelog
 
+HEAD
+
+- Add option to set merge method (merge, squash or rebase). (Example: `mp merge --merge-method squash`)
+
+---
+
 2021-05-22 - v0.0.32
 
 - Adds - `--diff` flag added to `mp plan` to show the diff of the changes made in each repo

cmd/merge.go

@@ -2,6 +2,7 @@ package cmd
 
 import (
 	"context"
+	"fmt"
 	"log"
 	"os"
 	"path/filepath"
@@ -19,10 +20,13 @@ import (
 var mergeFlagThrottle string
 var mergeFlagIgnoreReviewApproval bool
 var mergeFlagIgnoreBuildStatus bool
+var mergeMethod string
 
 // rate limits the # of PR merges. used to prevent load on CI system
 var mergeThrottle *time.Ticker
 
+var supportedMergeMethods = []string{"merge", "squash", "rebase"}
+
 var mergeCmd = &cobra.Command{
 	Use:   "merge",
 	Short: "Merge pushed changes",
@@ -46,6 +50,10 @@ var mergeCmd = &cobra.Command{
 			mergeThrottle = time.NewTicker(dur)
 		}
 
+		if !contains(supportedMergeMethods, mergeMethod) {
+			log.Fatalf("Invalid --merge-method: %s", mergeMethod)
+		}
+
 		err = parallelize(repos, mergeOneRepo)
 		if err != nil {
 			log.Fatal(err)
@@ -92,6 +100,7 @@ func mergeOneRepo(r lib.Repo, ctx context.Context) error {
 		CommitSHA:             pushOutput.CommitSHA,
 		RequireReviewApproval: !mergeFlagIgnoreReviewApproval,
 		RequireBuildSuccess:   !mergeFlagIgnoreBuildStatus,
+		MergeMethod:           mergeMethod,
 	}
 	var output merge.Output
 	if r.IsGitlab() {
@@ -113,3 +122,19 @@ func mergeOneRepo(r lib.Repo, ctx context.Context) error {
 	writeJSON(output, mergeOutputPath)
 	return nil
 }
+
+func init() {
+	mergeCmd.Flags().StringVarP(&mergeFlagThrottle, "throttle", "t", "30s", "Throttle number of merges, e.g. '30s' means 1 merge per 30 seconds")
+	mergeCmd.Flags().BoolVar(&mergeFlagIgnoreReviewApproval, "ignore-review-approval", false, "Ignore whether or not the review has been approved")
+	mergeCmd.Flags().BoolVar(&mergeFlagIgnoreBuildStatus, "ignore-build-status", false, "Ignore whether or not builds are passing")
+	mergeCmd.Flags().StringVarP(&mergeMethod, "merge-method", "m", "merge", fmt.Sprintf("Merge method to use. Possible values include: %s", strings.Join(supportedMergeMethods, ", ")))
+}
+
+func contains(list []string, item string) bool {
+	for _, each := range list {
+		if each == item {
+			return true
+		}
+	}
+	return false
+}

cmd/root.go

@@ -31,9 +31,6 @@ func init() {
 	rootCmd.AddCommand(docsCmd)
 
 	rootCmd.AddCommand(mergeCmd)
-	mergeCmd.Flags().StringVarP(&mergeFlagThrottle, "throttle", "t", "30s", "Throttle number of merges, e.g. '30s' means 1 merge per 30 seconds")
-	mergeCmd.Flags().BoolVar(&mergeFlagIgnoreReviewApproval, "ignore-review-approval", false, "Ignore whether or not the review has been approved")
-	mergeCmd.Flags().BoolVar(&mergeFlagIgnoreBuildStatus, "ignore-build-status", false, "Ignore whether or not builds are passing")
 
 	rootCmd.AddCommand(planCmd)
 	planCmd.Flags().StringVarP(&planFlagBranch, "branch", "b", "", "Git branch to commit to")

merge/merge.go

@@ -23,6 +23,8 @@ type Input struct {
 	RequireReviewApproval bool
 	// RequireBuildSuccess specifies if the PR must have a successful build before merging
 	RequireBuildSuccess bool
+	// Merge method to use. Possible values include: "merge", "squash", and "rebase"
+	MergeMethod string
 }
 
 // Output from Push()
@@ -95,7 +97,9 @@ func GitHubMerge(ctx context.Context, input Input, repoLimiter *time.Ticker, mer
 	}
 
 	// Merge the PR
-	options := &github.PullRequestOptions{}
+	options := &github.PullRequestOptions{
+		MergeMethod: input.MergeMethod,
+	}
 	commitMsg := ""
 	<-mergeLimiter.C
 	<-repoLimiter.C