feat: allow to pr krew plugin manifests (#3915)

following up on #3903

Signed-off-by: Carlos A Becker <caarlos0@users.noreply.github.com>

internal/pipe/krew/krew.go

@@ -328,7 +328,22 @@ func doPublish(ctx *context.Context, manifest *artifact.Artifact, cl client.Clie
 		return err
 	}
 
-	return cl.CreateFile(ctx, author, repo, content, gpath, msg)
+	if !cfg.Index.PullRequest.Enabled {
+		return cl.CreateFile(ctx, author, repo, content, gpath, msg)
+	}
+
+	log.Info("brews.pull_request enabled, creating a PR")
+	pcl, ok := cl.(client.PullRequestOpener)
+	if !ok {
+		return fmt.Errorf("client does not support pull requests")
+	}
+
+	if err := cl.CreateFile(ctx, author, repo, content, gpath, msg); err != nil {
+		return err
+	}
+
+	title := fmt.Sprintf("Updated %s to %s", ctx.Config.ProjectName, ctx.Version)
+	return pcl.OpenPullRequest(ctx, repo, cfg.Index.PullRequest.Base, title)
 }
 
 func buildManifestPath(folder, filename string) string {

internal/pipe/krew/krew_test.go

@@ -310,6 +310,59 @@ func TestFullPipe(t *testing.T) {
 	}
 }
 
+func TestRunPipePullRequest(t *testing.T) {
+	folder := t.TempDir()
+	ctx := testctx.NewWithCfg(
+		config.Project{
+			Dist:        folder,
+			ProjectName: "foo",
+			Krews: []config.Krew{
+				{
+					Name:             "foo",
+					Homepage:         "https://goreleaser.com",
+					ShortDescription: "test",
+					Description:      "Fake desc",
+					Index: config.RepoRef{
+						Owner:  "foo",
+						Name:   "bar",
+						Branch: "update-{{.Version}}",
+						PullRequest: config.PullRequest{
+							Enabled: true,
+						},
+					},
+				},
+			},
+		},
+		testctx.WithVersion("1.2.1"),
+		testctx.WithCurrentTag("v1.2.1"),
+	)
+	path := filepath.Join(folder, "dist/foo_darwin_all/foo")
+	ctx.Artifacts.Add(&artifact.Artifact{
+		Name:   "foo_macos.tar.gz",
+		Path:   path,
+		Goos:   "darwin",
+		Goarch: "all",
+		Type:   artifact.UploadableArchive,
+		Extra: map[string]interface{}{
+			artifact.ExtraID:       "foo",
+			artifact.ExtraFormat:   "tar.gz",
+			artifact.ExtraBinaries: []string{"foo"},
+		},
+	})
+
+	require.NoError(t, os.MkdirAll(filepath.Dir(path), 0o755))
+	f, err := os.Create(path)
+	require.NoError(t, err)
+	require.NoError(t, f.Close())
+
+	client := client.NewMock()
+	require.NoError(t, runAll(ctx, client))
+	require.NoError(t, publishAll(ctx, client))
+	require.True(t, client.CreatedFile)
+	require.True(t, client.OpenedPullRequest)
+	golden.RequireEqualYaml(t, []byte(client.Content))
+}
+
 func TestRunPipeUniversalBinary(t *testing.T) {
 	folder := t.TempDir()
 

internal/pipe/krew/testdata/TestRunPipePullRequest.yaml

@@ -0,0 +1,24 @@
+apiVersion: krew.googlecontainertools.github.com/v1alpha2
+kind: Plugin
+metadata:
+  name: foo
+spec:
+  version: v1.2.1
+  platforms:
+    - bin: foo
+      uri: https://dummyhost/download/v1.2.1/foo_macos.tar.gz
+      sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+      selector:
+        matchLabels:
+          os: darwin
+          arch: amd64
+    - bin: foo
+      uri: https://dummyhost/download/v1.2.1/foo_macos.tar.gz
+      sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+      selector:
+        matchLabels:
+          os: darwin
+          arch: arm64
+  shortDescription: test
+  homepage: https://goreleaser.com
+  description: Fake desc

www/docs/customization/krew.md

@@ -61,6 +61,20 @@ krews:
       # provided to GoReleaser
       token: "{{ .Env.HOMEBREW_TAP_GITHUB_TOKEN }}"
 
+      # Sets up pull request creation instead of just pushing to the given branch.
+      # Make sure the 'branch' property is different from base before enabling
+      # it.
+      #
+      # Since: v1.17
+      pull_request:
+        # Whether to enable it or not.
+        enabled: true
+
+        # Base branch of the PR.
+        #
+        # Default: default repository branch.
+        base: main
+
     # URL which is determined by the given Token (github or
     # gitlab)
     # Default: